Chemistry

Medulla K+ yellow turning red. TLC: norstictic acid (n = 1).

Taxonomic notes

The specimen considered here does not present the typical alate branches of U. angulata with trapezoidal segments. Instead, we observed the upper areolate surface splitting off as scale-like propagules (schizidia) (Fig. 8F). According to Truong et al. (Reference Truong, Rodriguez and Clerc2013b), U. angulata presents a wide range of variability regarding the shape of the branches (alate, ridged or squamulose). The sequenced specimen (Truong id-85) is similar to the specimen analyzed here; both share the pendulous thallus with ridged branches and the presence of norstictic acid in the medulla, but they differ in geographic distribution (Peru vs the Philippines) and their ITS sequences (see under Phylogenetic notes). The specimen from Peru corresponds to a young thallus without schizidia. More sequenced specimens of U. angulata need to be analyzed to better understand its variability.

Regarding the chemistry, although caperatic acid is reported for this species (Ohmura Reference Ohmura2012, Reference Ohmura2020), we did not find that compound in the specimen analyzed here. Ohmura (Reference Ohmura2020) suggested that this fatty acid is always present in this species (worldwide material, although the amount varies from major to trace) and recommended using a microcrystal test and TLC to detect its presence.

Usnea transitoria Motyka is a similar neotropical species, in having terete to slightly ridged segments and conspicuous bands of eroded cortex with areas of regeneration along main branches (Truong et al. Reference Truong, Rodriguez and Clerc2013b). It differs from the specimen analyzed here mainly by the chemistry (norstictic acid instead of stictic acid found in U. transitoria). Other differences include the absence of tubercles (present in U. transitoria) and the geographical distribution, neotropical versus pantropical.

Phylogenetic notes

Despite being a relatively common and widespread species, there is only one ITS sequence for U. angulata published in GenBank (Truong id-85). The specimen PU04 is morphologically and phylogenetically close (but not supported and as a long branch, pairwise similarity = 0.95) to Usnea angulata from Peru (Truong id-85) (Fig. 2B). Usnea angulata is also closely related to U. nipparensis Asahina, despite being morphologically very different (for more details see Ohmura (Reference Ohmura2020)). Given the morphological, chemical and molecular differences, it is possible that the Philippine material is not U. angulata s. str. but represents a separate taxon; however, more material needs to be sequenced to test this hypothesis.

Distribution

Usnea angulata is widely distributed in temperate to subtropical regions in East Asia (Ohmura Reference Ohmura2001). This is the first record for the Philippines.

Specimen examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1131 m, 7.45462°N, 125.23664°E, beginning of trail to Epol Waterfall, part way down, on fallen branch, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/954 (G), DNA-code: PU04.

Chemistry

Medulla K+ yellow turning red. TLC (n = 15): norstictic and ±salazinic acids, ±zeorin, ±protocetraric acid (trace).

Taxonomic notes

Usnea baileyi is easily recognized by the hollow and thick (>50%) central axis, by the pink-pigmented narrow medulla and by the punctiform soralia. The density of ramifications, fibrils and isidiomorphs varies among individuals, as also indicated in Truong & Clerc (Reference Truong and Clerc2013).

Phylogenetic notes

Usnea baileyi most probably represents a complex of several species, as evidenced by the presence of a geographical signal and supported phylogenetic structure, even within a single area (Temu et al. Reference Temu, Clerc, Tibell, Tibuhwa and Tibell2019; Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020). Although U. baileyi is reported as subcosmopolitan (https://www.gbif.org/species/7247545) and known from the Americas (e.g. Osorio Reference Osorio1992; Truong & Clerc Reference Truong and Clerc2013; Herrera-Campos Reference Herrera-Campos2016), sequenced specimens are available only from Africa (Temu et al. Reference Temu, Clerc, Tibell, Tibuhwa and Tibell2019; Nadel & Clerc Reference Nadel and Clerc2022), Asia, Hawaii (Ohmura Reference Ohmura2002) and now from the Philippines. Unfortunately, no sequence from the type region (Australia) is yet available. The sequenced specimens from the Philippines clustered into two different clades: one entirely with specimens from the Philippines (baileyi-1: PU01, PU26, PU37) and one (baileyi-2) with five Asian specimens (Ohmura 4488A, Id-Li 314, PU24, PU44) together with one from Hawaii as a long branch (Ohmura 4516) and with a different morphology (Fig. 2A).

In the ‘baileyi-1’ clade, the tubular section is filled with very loose, arachnoid, white or orange-yellow hyphae (the colour might vary in the same branch), and the subcortical/medullary pigment is salmon-coloured. In contrast, in the Philippines specimens of the ‘baileyi-2’ clade, the tubular part is denser and more spongy, white to pale yellow or cream-coloured, and the subcortical/medullary pigment is pale yellow-orange. However, the specimen Ohmura 4488a belonging to ‘baileyi-2’ has a ‘baileyi-1’ type of tubular section. The thin pigmented section of the medulla is often pink but sometimes also yellow to ochraceous. Only one specimen from the Philippines (PU44) does not have the pink pigment but a yellow pigmentation. The analysis of more specimens with molecular tools is necessary to possibly find morphological differences between these two clades (Fig. 3).

The chemistry of the Philippine specimens is rather uniform, with norstictic acid accompanied or not by salazinic acid and zeorin (see Chemistry above). Sequenced specimens from Tanzania and São Tomé also have salazinic and norstictic acids (Temu et al. Reference Temu, Clerc, Tibell, Tibuhwa and Tibell2019; Nadel & Clerc Reference Nadel and Clerc2022) but apparently without zeorin. In addition to norstictic acid and zeorin, eumitrins (red pigment present in the medulla) were found in specimens from Japan and Taiwan (Ohmura Reference Ohmura2001, Reference Ohmura2012). Eumitrins and zeorin were also reported from South American specimens (Truong & Clerc Reference Truong and Clerc2013). The presence of many chemotypes, the large distribution area and the morphological variation are good indications that U. baileyi is a complex of species, as shown recently (Temu et al. Reference Temu, Clerc, Tibell, Tibuhwa and Tibell2019; Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020). At least two names are good candidates for one or both of these two clades found in the Philippines: U. chrysopoda and U. endorhodina. Further studies of these different types are necessary before reaching any taxonomic conclusion. A more in depth study, taking into account all the distribution range and chemistry variation, with the help of molecular tools is necessary to better understand this aggregate.

Distribution

Usnea baileyi has been reported from Luzon, Mindanao and Palawan Islands (Santiago et al. Reference Santiago, Borricano, Canal, Marcelo, Perez and dela Cruz2010, Reference Santiago, Sangvichien, Boonpragob and dela Cruz2013; Sipman et al. Reference Sipman, Diederich and Aptroot2013; Galinato et al. Reference Galinato, Mangubat, Leonor, Cababa, Cipriano and Santiago2017, Reference Galinato, Baguino and Santiago2018; Timbreza et al. Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017). In the present study, it was also found in Mindanao (Marilog Forest Reserve) and Negros (Balinsasayao Twin Lakes Natural Park). This is the first record for Negros.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1202 m, 7.45392°N, 125.24509°E, anthropized area, corticolous on Pinus sp., 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/897a (BRIT), DNA-code: PU01; ibid., 1227 m, 7.45938°N, 125.25106°E, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/893a (BRIT), DNA-code: PU37; ibid., 1279 m, 7.48936°N, 125.25365°E, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/981b (G), DNA-code: PU24; ibid., 1184 m, trail with native plants, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 1012a (G), DNA-code: PU44. Negros: Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, fernery behind restaurant, 909 m, 9.36083°N, 123.17846°E, planted edible ferns and coconut palms, on coconut tree, 2019, M. Dal Forno (with A. Gerlach & A. D. Nietes) 3493 (BRIT), DNA-code: PU26.

Chemistry

Medulla K+ yellow. TLC: 1) stictic, constictic (trace), ±menegazziaic (trace), ±cryptostictic (trace), ±norstictic (trace) and ±lobaric acids (n = 18); 2) barbatic, ±stictic and ±salazinic acids, ±US1, US2 (n = 4); 3) stictic and salazinic acids, ±US1, US2 (n = 2); 4) norstictic, ±salazinic and ±protocetraric acids (trace) (n = 2).

Taxonomic notes

Usnea bismolliuscula is easily recognized by the erect to subpendent thallus with constricted lateral branches, ±inflated segments, a glossy and smooth cortex surface with perforations, soralia that are circular to irregular in shape and even with the cortex surface, a thick and lax medulla and by the presence of stictic acid as the main medullary compound. The lax medulla with conglutinated hyphae and the large soralia at terminal branches (Fig. 9F & G) are good characters to separate this species from U. yoshihitoi. In the southern Philippines, U. bismolliuscula displays four chemotypes. In addition to the stictic acid chemotype (n = 18), we found four specimens with barbatic acid, two specimens with stictic and salazinic acids and two specimens with norstictic acid as the main medullary substance. Ohmura (Reference Ohmura2001) mentioned the presence of only two chemotypes in Japan: stictic acid (98%) with squamatic acid as accessory and thamnolic acid (2%).

Phylogenetic notes

The six sequences from the Philippines (PU02, PU12, PU22, PU50, PU67, PU68) cluster into a fully supported clade (BP = 100) with three U. bismolliuscula specimens from Taiwan (Li251, Li322, Li261); the identity of one specimen (Li261), stictic acid-deficient, should, however, be checked. Twenty sequences from Japan and Taiwan were added to this study, often with stictic acid as the main medullary compound (except YO4840). One sequenced specimen (PU67) also contains barbatic acid with stictic acid. This sequence, however, is of low quality and appears as a long branch in the phylogeny (Fig. 2D).

Our phylogenetic analysis shows that in the Philippines there are two distinct lineages within the Usnea bismolliuscula morphotype (perforations of the cortex); one is described here as a new species, U. yoshihitoi (Figs 2 & 9; see under this taxon for differences with U. bismolliuscula). This is the first phylogenetic evidence that perforation of the cortex may have evolved several times within the genus.

Distribution

Usnea bismolliuscula is known from India (Awasthi Reference Awasthi1986), Australia (Stevens Reference Stevens1999), Japan and Taiwan (Ohmura Reference Ohmura2001, Reference Ohmura2012). It was reported for the first time in the Philippines, in Bukidnon (Mindanao), by Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017). Our study shows that it is a common species found in Mindanao (Marilog Forest Reserve) and Negros (Balinsasayao Twin Lakes Natural Park, Cuernos de Negros) where it occurs on tree trunks (e.g. Pinus sp., coconut palm) and on thin branches of shrubs (e.g. Medinilla sp.). It can also be found in anthropized habitats. It is reported here for the first time from the island of Negros.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1227 m, 7.45938°N, 125.25106°E, on Pinus sp., 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/897b (BRIT), DNA-code: PU02, AG 2019/950d (dupl. G, PNH, CMHU, BRIT), DNA-code: PU50, AG 2019/951 (G), DNA-code: PU22, AG 2019/957a (G), DNA-code: PU12. Negros: Negros Oriental, Dumaguete City, Balinsasayao Twin Lakes Natural Park, 893 m, 9.35281°N, 123.18253°E, on branches on the ground, 2019, A. Gerlach (with A. D. Nietes) AG 2019/627b (BRIT).

Chemistry

Medulla K−, P+ yellow turning red. TLC: protocetraric and ±psoromic acids (n = 2).

Taxonomic notes

Usnea brasiliensis can be recognized by the shrubby thallus with constricted lateral branches, by the minute consoralia ±even with cortex, by the shiny, thin to moderately thick cortex, ((5–)5.4–6.8%–8.2(–10.5)), the thick medulla ((26.5–)30.5–33.3%–36.1(–37.5)) with an M/C ratio smaller than 7, highlighting a relatively thick cortex and a not too large medulla (Gerlach et al. Reference Gerlach, Borges da Silveira, Rojas and Clerc2020), and the presence of protocetraric, ±psoromic acids in the medulla. The two specimens collected in the Philippines share the characteristics mentioned above except that their soralia remain well delimited, apparently not forming consoralia.

We found a herbarium specimen collected in Luzon and apparently belonging to U. brasiliensis s. lat. (B 56256). It has a CMA of the tenuicorticata-type (ratio medulla/cortex higher than 7) and an interesting chemistry with protocetraric acid and lobaric acid; the soralia are punctiform, with a thin cortical margin, with many isidiomorphs, fusing together to form consoralia as in U. cornuta Körb. This specimen could be a new chemotype of U. tenuicorticata P. Clerc & A. Gerlach. Molecular analysis of this chemotype is necessary to confirm whether U. tenuicorticata is present in the Philippines.

Phylogenetic notes

Sequences were obtained for two specimens belonging to the U. brasiliensis aggregate (PU41, PU52) (Fig. 2E). PU41 clustered together with U. brasiliensis s. str. but on a long branch (similarity between Usnea brasiliensis epitype and PU41 = 0.91 [below 98.5%]), which indicates that they probably do not correspond to the same lineage. Since PU41 is phylogenetically closely related to and shares a similar phenotype with U. brasiliensis s. str., only diverging in their geography, we could consider it as a potentially unnamed allo-cryptic species (Lücking et al. Reference Lücking, Leavitt and Hawksworth2021). Our results indicate that what we consider morphologically and chemically as U. brasiliensis s. lat. in the Philippines seems to be a phylogenetically highly heterogeneous complex that needs further study.

Distribution

Usnea brasiliensis is known for South and North America, Macaronesia, Japan and Taiwan (see Gerlach et al. (Reference Gerlach, Borges da Silveira, Rojas and Clerc2020) for more details). This is the first evidence that the U. brasiliensis aggregate occurs in the Philippines (Mindanao and Luzon Islands).

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1258 m, 7.48853°N, 125.25288°E, Mt Malambo, base, by the road, right in front of Royal Mandala forest farm, anthropized environment, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/995b (BRIT), DNA-code: PU41; ibid., 1188 m, 7.45960°N, 125.24522°E, disturbed forest with Pinus, abandoned house, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/950c (G), DNA-code: PU52.

Chemistry

Medulla K+ yellow turning red. TLC: constictic , salazinic and ±protocetraric acids (n = 13).

Taxonomic notes

Usnea confusa belongs to the U. cornuta aggregate. It was considered as a synonym of U. cornuta by Clerc (Reference Clerc2004) and recently lectotypified by Ohmura & Clerc (Reference Ohmura and Clerc2019). Morphologically it is difficult to find any differences between these two taxa. Both can be recognized by the erect-shrubby thallus, the minute soralia, the numerous papillae covering the branches, the presence of isidiofibrils, and the presence of salazinic and constictic acids in the medulla. Usnea confusa and U. cornuta can be considered allo-(phylo-) cryptic taxa sensu Dal Forno et al. (Reference Dal Forno, Lawrey, Moncada, Bungartz, Grube, Schuettpelz and Lücking2022), meaning they have the same phenotype and are phylogenetically closely related but differ mainly in their geographical distribution (Asia vs Europe).

Phylogenetic notes

We sequenced four specimens (PU03, PU10, PU18, PU38) that clustered together with the Japanese specimens identified as Usnea confusa-1 by Ohmura & Clerc (Reference Ohmura and Clerc2019) in a supported clade (Fig. 2C). Usnea confusa is phylogenetically close to Usnea cornuta s. str. and whether both species are separate or not is controversial.

The U. cornuta aggregate was studied by Gerlach et al. (Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019), who reconstructed a phylogenetic tree based on a coalescence approach with three molecular markers. They found 14 lineages and suggested that lineage 5 (more specifically the subclade 5A) corresponds to U. cornuta s. str. In this multilocus study, sequences from U. confusa were not included. Later, the phylogenetic position of U. confusa was investigated and two clades were found, both in the vicinity of U. cornuta s. str. (Ohmura & Clerc Reference Ohmura and Clerc2019). According to these authors, their results based on ITS sequences do not allow the confirmation or rejection of the conspecificity of both taxa.

Lücking et al. (Reference Lücking, Nadel, Araujo and Gerlach2020), with an expanded ITS dataset, agreed that lineage 5 (Gerlach et al. Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019) corresponds to Usnea cornuta s. str. but also identified many other, possibly unnamed lineages (U. aff. cornuta 1–10). Gerlach et al. (Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019) pointed out that even lineage 5 includes smaller subgroups whose relationships are poorly understood. Whether these putative unnamed subgroups can be considered as separate species or not should be carefully analyzed case by case, especially when only ITS data are available. Here we propose to accept U. confusa as a separate species based on genetic distance (between U. confusa and U. cornuta = 98.7–99%; see Fig. 4), and because all specimens of U. confusa form a coherent unit within a well-supported clade with only Asian specimens. Although the genetic distance is minor, barcode evidence from other taxa shows that closely related species in Usnea display a genetic distance of 99–99.5% (Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020). It is important to note, however, that a definitive decision regarding the conspecificity of Usnea cornuta s. str. and Usnea confusa will only be possible if based on multilocus analyses and the study of type material.

Figure 4. Alignment of the three clades of the Usnea cornuta aggregate showing the variable columns diagnostic for the clades: U. confusa vs U. cornuta (small clade: rows 5–7), 5 substitutions, including 2 transversions; U. confusa vs U. cornuta (large clade: rows 8–26), 8 substitutions, including 5 transversions; U. cornuta (small vs large clade): 5 substitutions, all transversions. In colour online.

Distribution

Usnea confusa was previously known only from Japan (Ohmura & Clerc Reference Ohmura and Clerc2019). This is the first record for the Philippines (Mindanao and Negros).

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1227 m, 7.45938°N, 125.25106°E, on the new Baganinhan road, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/893b (BRIT, PNH), DNA-code: PU38; ibid., on Pinus sp., 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/897c (G), DNA-code: PU03, AG 2019/995c (G), DNA-code: PU10, AG 2019/996b (BRIT), DNA-code: PU18. Negros: Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, highest point reached, 1040 m, 9.35947°N, 123.17361°E, on tree trunk, 2019, M. Dal Forno (with J. Shevock & D. Salas) 3471a (BRIT).

Chemistry

Medulla K+ yellow turning red. TLC: barbatic and salazinic and ±norstictic acids (n = 12).

Nomenclatural note

This taxon was named U. pangiana Stirt. by Ohmura (Reference Ohmura2001). However, as Clerc (Reference Clerc2016) pointed out, the holotype of U. pangiana has much larger and stipitate soralia, not cornuta-like in morphology, that are probably growing out of fibercles or tubercles. Although Clerc (Reference Clerc2016) treated this taxon as U. hondoensis Asahina, the name U. croceorubescens Vain. should be applied since it was published earlier (in 1956 and 1921 respectively). The morphology and chemistry of the type specimens of U. croceorubescens, including the ratios of cortex, medulla and axis, coincide well with the range of description provided by Ohmura (Reference Ohmura2001). However, as described in the protologue of U. croceorubescens (‘Stratum myelohyphicum crebre contextum, partim croceo-rubescens’), the medulla is partly yellow-red in colour while it is white in most parts. This colour finds its origin in the deposition of salazinic acid crystals, which might be caused by withering of the thallus in old parts. Such rusty coloration by withering is also common in many lichens that contain salazinic acid. Although the epithet ‘croceorubescens’ is not representative of the features of this taxon, the earliest legitimate name should be applied according to ICN 11.3 (Shenzhen Code).

Taxonomic notes

Usnea croceorubescens is characterized by the erect-shrubby to subpendent sorediate thallus, with non-constricted lateral branches, by the presence of numerous thin annular cracks (sometimes best seen in transversal section) especially near the base, by the punctiform soralia that are even to slightly stipitate and often regularly distributed in the whole thallus, rarely with isidiomorphs, by the matt, moderately thick to thick cortex and by the presence of barbatic and salazinic acids as main secondary metabolites.

Usnea aciculifera Vain. has a different %C/M/A, soralia that are more or less aggregated in small groups and stictic acid in the medulla. Usnea setulosa Motyka, a South American species, is morphologically similar (soralia and %C/M/A). However, this species has a black base and salazinic acid in the medulla. Several other species are known to produce barbatic acid in the medulla: Usnea dendritica Stirt. seems to be the most similar species due to the presence of annular cracks and the similar chemistry; however, it is richly apotheciate and differs mainly by the shape of the rare soralia developed from the top of eroded papillae, which are distinctly stipitate in thicker branches (Ohmura Reference Ohmura2001).

Phylogenetic notes

Four sequenced specimens (PU23, PU31, PU34, PU46) form a well-supported subclade (BP = 98) within the Usnea croceorubescens clade from Japan (Fig. 2C).

Distribution

Usnea croceorubescens is known from Japan and Taiwan (Ohmura Reference Ohmura2001, Reference Ohmura2012; as U. pangiana). This is the first record for the Philippines where it is relatively common (Luzon, Mindanao and Negros).

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1279 m, 7.48936°N, 125.25365°E, 2019, Mt Malambo, open area with Pinus sp., A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/992b (BRIT), DNA-code: PU23. Negros: Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, highest point reached, 1040 m, 9.35947°N, 123.17361°E, on tree trunk, 2019, M. Dal Forno (with J. Shevock & D. Salas) 3471b (BRIT), DNA-code: PU31; Dumaguete City, Santa Catalina, San Pedro, Cuernos de Negros, 1324 m, 9.24092°N, 123.11626°E, mid elevation, forest edge (Cyphellostereum, Crocynia, Cryptothecia), 2019, A. Gerlach (with M. Dal Forno, A. D. Nietes) AG 2019/852a-b (BRIT, dupl. PNH), DNA-code: PU34, AG 2019/850a (G), DNA-code: PU46.

Chemistry

Medulla K+ yellow turning red. TLC: salazinic, norstictic and galbinic acids (n = 9).

Taxonomic notes

Usnea dasaea is characterized by the irregular branches in longitudinal section, terete in transversal section, often partly densely covered by spinulose fibrils, the C/M/A of cornuta-type, the minute, plane and often irregular soralia and the presence of galbinic acid in the medulla. For differences with U. paleograndisora and U. spinulifera, see under these taxa.

Phylogenetic notes

Two specimens from the Philippines (PU09, PU21) clustered with one specimen from Japan (AB051056). The specimen from Portugal (DN121) is in their vicinity but their relationship is not supported (Fig. 2A). According to Gerlach et al. (Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019), Usnea dasaea (from Brazil) appears to form two separate lineages (lineage 1: 35BR; lineage 2: 34BR, 37BR, 128BR), although they were poorly supported. These lineages are not closely related to the lineage from Asia which suggests that Usnea dasaea is polyphyletic (Fig. 2A).

Distribution

Usnea dasaea is known from Europe, North America, South America, Africa, Asia (Clerc & Herrera-Campos Reference Clerc and Herrera-Campos1997) and Australasia (Stevens Reference Stevens1999 (as U. undulata); Bannister et al. Reference Bannister, Harrold and Blanchon2020). However, since it is a polyphyletic complex (Gerlach et al. Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019), it is difficult to have an exact idea of its distribution. For the Philippines, it has been reported for Luzon (Galinato et al. Reference Galinato, Mangubat, Leonor, Cababa, Cipriano and Santiago2017, Reference Galinato, Baguino and Santiago2018). It is recorded here for the first time from the southern Philippines, specifically Mindanao.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 7.45672°N, 125.23962°E, 1095 m, open road, disturbed, close to the main road near Lawi Lawi Resort, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/969c (BRIT), DNA-code: PU09; Mt Malambo, open area with Pinus sp., 1279 m, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/980b (BRIT), DNA-code: PU21.

Chemistry

1) Medulla K+ yellow turning red; TLC: salazinic, ±norstictic and ±protocetraric (trace) acids (n = 3). 2) Medulla K+ yellow (n = 1); TLC: constictic acid (n = 1).

Taxonomic notes

Morphologically, what is called here U. himalayana is similar to U. articulata (L.) Hoffm. Both taxa have sausage-like inflated branches with or without pseudocyphellae, a thin (1.5–5.5%) and glossy cortex, a lax and wide (35–45%) medulla, a thin (7–20%) central axis, a low A/M ratio (0.2–0.6), a fairly large M/C ratio (6.5–26.8) and thus a tenuicorticata-type of C/M/A (Ohmura Reference Ohmura2001, Reference Ohmura2012; Nadel & Clerc Reference Nadel and Clerc2022). The type of Usnea himalayana (collected in India, Himalaya) produces salazinic acid in the medulla whereas the type of U. articulata (collected in the UK) has protocetraric acid. The diffractaic acid chemotype of U. articulata was found in Taiwan (Ohmura Reference Ohmura2012); the salazinic, diffractaic and protocetraric acid chemotypes were found in Africa (Swinscow & Krog Reference Swinscow and Krog1976; Nadel & Clerc Reference Nadel and Clerc2022). Despite this similar morphology and anatomy, our ITS phylogeny (Fig. 2E) shows that both species are not closely related. See below for differences with Usnea nidifica, another pendulous species occurring in the Philippines.

Phylogenetic notes

Unfortunately, no ITS data from specimens of U. himalayana collected in the Philippines are available. We used ITS data from three specimens collected in Malaysia and Taiwan. These specimens are closely related to U. nidifica (Fig. 2E).

Distribution

Known from the Himalayan region (India, Nepal, Sikkim) (Motyka Reference Motyka1936–38 (as U. dichotoma); Awasthi Reference Awasthi1986; Ohmura Reference Ohmura2001), from Malaysia, the Philippines and Taiwan (Ohmura Reference Ohmura2012). Recently reported for the Philippines from Mindanao (Bukidnon Province) by Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017). In our study, only herbarium specimens were analyzed (Mindanao and Luzon). The species is recorded here for the first time from Luzon. Also new to Papua New Guinea.

Selected specimens examined

Philippines: Luzon: Benguet Province, Mt Santo Tomas, S of Baguio, along road from telecommunication station to Baguio, 2100 m, 16°18ʹN, 120°35ʹE, 1987, H. Sipman 21744 (B 73258).—Papua New Guinea: Simbu: Bismarck Range, Mt Wilhelm, Pindaunde Valley, SE of Lake Aunde, 1966, D. J. Hill 12578 (G 262519).

Chemistry

Medulla K+ yellow. TLC: stictic, constictic, cryptostictic, menegazziaic and norstictic acids.

Taxonomic notes

Usnea krogiana is characterized by the shrubby-sorediate thallus with lateral branches not constricted at attachment points, the black base with a sharply delimited pigmentation, the thick axis that gives the distinct rigidity to the thallus, the matt cortex, the numerous minute soralia with conspicuous isidiomorphs and by the presence of the stictic acid group in the medulla (Clerc Reference Clerc2006). The only sequenced specimen (PU35) corresponds well with U. krogiana with the exception of the axis that is moderately thick (43%) (axis thickness in Clerc (Reference Clerc2016): (44–)53.6–62.5%–71.4(–79)) and by the chemistry (salazinic acid instead of stictic acid). The presence of salazinic acid in U. krogiana was reported for the first time as a new chemotype from the islands of Sao Tomé and Principe by Nadel & Clerc (Reference Nadel and Clerc2022), based on a sequenced specimen.

Phylogenetic notes

The only sequenced specimen (PU35) clustered with strong support with a specimen recently identified as U. krogiana from São Tome and Principe (Nadel & Clerc Reference Nadel and Clerc2022) (Fig. 2C).

Distribution

Usnea krogiana occurs in Macaronesia and the West Indies (Clerc Reference Clerc2006), and in Africa (Nadel & Clerc Reference Nadel and Clerc2022). It is reported here for the first time for Asia in the Philippines (Negros and Mindanao).

Selected specimens examined

Philippines: Negros: Negros Oriental, Dumaguete City, Santa Catalina, San Pedro, Cuernos de Negros, forest going up the ridge to peak Hapon Hapon, 1368 m, 9.24245°N, 123.11779°E, 2019, M. Dal Forno, A. Gerlach & A. D. Nietes 3635a (G), DNA-code: PU35.

Chemistry

Medulla K−. TLC (n = 1): diffractaic acid.

Taxonomic notes

Usnea longissima can be easily confused with specimens belonging to the U. pectinata aggr., especially when the latter have an eroded cortex and a non-pigmented central axis. Moreover, both taxa might produce diffractaic acid in the medulla. In that case, the presence of the spirally arranged maculae in the lateral branches is a diagnostic character of U. longissima. Usnea pectinata might also have maculae but these are ±elongated, of irregular shape, and never spirally arranged. The specimen found in the TUR herbarium has the characteristic pseudocyphellae and diffractaic acid in the medulla.

Phylogenetic notes

DNA from the TUR herbarium specimen was not extracted. Usnea longissima belongs to the subgenus Dolichousnea Y. Ohmura (Ohmura Reference Ohmura2001, Reference Ohmura2002).

Distribution

Usnea longissima is a circumpolar, Northern Hemisphere species, found in Europe, North America and Asia. In the Philippines, Vainio (Reference Vainio1909), Herre (Reference Herre1963) and Galinato et al. (Reference Galinato, Mangubat, Leonor, Cababa, Cipriano and Santiago2017, Reference Galinato, Baguino and Santiago2018) have reported it for Luzon at higher elevations.

Specimen examined

Philippines: Luzon: Benguet Province, Pauai, 2134 m, Vainio (TUR-V 591).

Chemistry

Medulla K+ yellow turning red. TLC: 1) salazinic, norstictic and protocetraric (trace) acids (n = 5); 2) salazinic and constictic acids (n = 1).

Taxonomic notes

The analyzed specimens have pendulous thalli with irregular branches and ±inflated segments, irregularly shaped soralia developing from cracks or directly from the cortex, partially aggregating to form irregular masses of soralia, a thin to moderately thin cortex (4–6–8%) and salazinic and norstictic acids as main medullary substances.

The herbarium specimen B 60 0073552 collected in Luzon by H. Sipman with short pendulous thalli (6 cm long) has rounded and slightly stipitate soralia which are somewhat atypical for this species. However, the irregular branches which are more or less inflated in some parts, the glossy surface of the cortex, the chemistry, and the %C/M/A (6/34/20) correspond well with U. nidifica. Another specimen (B 60 0073550 collected in 1987 in Luzon by Sipman) has the same rounded soralia and a different chemistry (constictic acid instead of salazinic).

As commented by Stevens (Reference Stevens and Galloway1991, Reference Stevens1999) and Ohmura (Reference Ohmura2001), U. nidifica seems to be a highly variable species. Indeed, Stevens (Reference Stevens1999) mentioned seven taxa as possible synonyms and Ohmura (Reference Ohmura2001) synonymized eight taxa under this species. A taxonomic revision based on molecular data analyzed from specimens collected in the whole Indo-Pacific area will be necessary to better understand this taxon.

In our phylogeny, U. himalayana is a sister clade to U. nidifica. However, the former species does not produce soralia and has an U. articulata-type of morphology, with swollen and distinctly articulate branches, a thinner cortex (1.5–5.5%), a much larger and lax medulla (35–43%), a much thinner axis (7–20%) and consequently a lower A/M (0.2–0.6). Usnea bismolliuscula is another similar species. It differs, however, in the presence of perforations in the cortex, in the conglutinated medullary hyphae and in the chemistry (stictic acid group).

Phylogenetic notes

Four sequenced specimens from the Philippines (PU28, PU30, PU33, PU54) cluster into a supported clade (PP = 69) sister to U. himalayana (see above) (Fig. 2E).

Distribution

Usnea nidifica is known from Asia (Japan, Java, India, Malaysia, Sulawesi and Taiwan), Africa (Comoro Islands, Mauritius, the Seychelles, Socotra), Australasia (Australia, New Caledonia, New Zealand, Papua New Guinea, Philippines) and the Pacific Islands (Fiji, Mariana Islands, Norfolk Island, Tahiti) (Motyka Reference Motyka1936–38; Stevens Reference Stevens and Galloway1991, Reference Stevens1999; Ohmura Reference Ohmura2001, Reference Ohmura2012; Galloway Reference Galloway2007). Usnea nidifica was recently reported for the Philippines from Mindanao (Bukidnon Province) by Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017). One specimen is recorded for Palawan (GBIF), but its identification needs to be confirmed. It is reported here for the first time from Negros (Balinsasayao Twin Lakes Natural Park).

Selected specimens examined

Philippines: Negros: Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, fernery behind restaurant, 909 m, 9.36083°N, 123.17846°E, planted edible ferns and coconut palms, on coconut tree, 2019, M. Dal Forno (with A. Gerlach & A. D. Nietes) 3483 (BRIT), DNA-code: PU33; ibid., on coconut palm, 2019, A. Gerlach (with A. D. Nietes) AG 2019/636c (G), DNA-code: PU54; ibid., 2019, M. Dal Forno 3496 (G), DNA-code: PU28; ibid., road before the park entrance, trees by the road, 782 m, 9.36707°N, 123.18211°E, anthropized area, on fallen branch, 2019, M. Dal Forno 3554 (G), DNA-code: PU30. Palawan Island: Distr. Brooke's Point, along trail from Macagua, at E-foot, to summit of Mt Mantalingahan, 900 m, 26 iv 1991, H. Sipman & B. Tan (B 60 0083619).

Chemistry

Medulla K+ yellow turning red. TLC: salazinic, norstictic and ±protocetraric (trace) acids (n = 6).

Etymology

This name refers to the similarity with Usnea cornuta and the presence of norstictic acid in the medulla.

Taxonomic notes

Usnea norsticornuta belongs to the Usnea cornuta aggregate; it has an erect-shrubby sorediate thallus with slightly constricted lateral branches, minute soralia that are even with the cortex surface (Fig. 5) and a soft cortex when cut with a razor blade. It differs from U. cornuta s. str. by the thicker cortex ((3.0–)5.0–6.4%–7.8(–11.5), n = 93 in U. cornuta s. str.), a larger ratio A/M ((0.3–)0.5–0.8–1.1(–2.1) in U. cornuta) and a smaller ratio M/C ((2.2–)3.7–5.3–6.9(–10.5) in U. cornuta s. str.). It differs from all other species of the U. cornuta aggr. by the presence of norstictic acid as the main medullary substance (Gerlach et al. Reference Gerlach, Borges da Silveira, Rojas and Clerc2020).

Usnea pygmoidea (Asahina) Ohmura, another species belonging to the U. cornuta aggr. found in the Philippines, differs from U. norsticornuta mainly by the absence of norstictic acid and by the thinner, on average, cortex (3–8%). In eastern Asia, several species have norstictic acid (±salazinic acid, ±protocetraric acid) as the sole main medullary substance (Ohmura Reference Ohmura2001): U. dendritica, U. masudana Asahina, U. pseudogatae Asahina and U. sinensis Motyka have numerous apothecia and no soralia; U. rubicunda Stirt. and U. rubrotincta Stirt. have a red-pigmented cortex; Usnea baileyi has a tubular cortex; U. angulata is a pendulous species with trapezoidal segments; U. dasaea has parts of branches with numerous and densely distributed spinulose fibrils; U. glabrescens s. lat. has larger soralia and a jet black-pigmented basal part; U. praetervisa (Asahina) P. Clerc has a jet black-pigmented basal part and a different type of C/M/A; U. nidifica has irregular soralia originating in ±longitudinal, irregular cracks in the cortex (see under that species).

Phylogenetic notes

The specimen PU11 is a singleton phylogenetically close to U. himalayana and U. nidifica. It is not related to any other species of the Usnea cornuta aggregate distinguished by Gerlach et al. (Reference Gerlach, Borges da Silveira, Rojas and Clerc2020) (Fig. 2E).

Distribution

Known so far only in the Philippines archipelago: Mindanao (Marilog Forest Reserve), Negros (Cuernos de Negros) and Luzon.

Selected paratypes

Philippines: Negros: Negros Oriental, Dumaguete City, Santa Catalina, San Pedro, Cuernos de Negros, 1523 m, 9.24918°N, 123.12500°E, forest going down past peak Hapon Hapon to Kanaway, fallen Usnea, close to mossy fern forest, 2019, A. Gerlach (with M. Dal Forno & A. D. Nietes) AG 2019/817 (BRIT). Luzon: Pampanga Province, Camp Stotsenburg (Mt Pinatubo) 1927, A. D. E. Elmer 22062 (B 56256, B 37149).

Chemistry

Medulla K+ yellow turning red. TLC: usnic, salazinic, norstictic and galbinic acids (n = 7).

Etymology

The name refers to the morphological similarity with Usnea grandisora Truong & P. Clerc and their geographical distribution in the Palaeotropics.

Taxonomic notes

Usnea paleograndisora is characterized by the shrubby entangled thallus with more than one attachment point to the substratum, by the presence of a thin orange subcortical pigmentation (sometimes not continuous), by the lateral branches not- to slightly constricted (Fig. 6), and by the presence of galbinic acid as main medullary chemistry. The soralia are large, circular to irregular, covering the terminal branches and fibrils, concave to plane and ±excavate, never stipitate. In addition, the cortex is moderately thick (on average) to thick, shiny in longitudinal section. The density of spinulose fibrils can vary greatly among specimens from few to numerous, as can the disposition from regular to irregular.

Usnea grandisora has the same type of soralia, but without a distinct cortical rim when circular and plane. The subcortical pigment is much stronger in this species and thus visible through the cortex, giving a distinct reddish colour to the thallus. Furthermore, and this is the most important and significant difference, U. grandisora has a much thinner medulla ((9.5–)13.7–18.1%–22.5(–26), n = 15), a thicker cortex ((8.5–)9.2–11.2%–13.2(16)) and central axis ((29–) 31.9–41.3%–50.7(–58)), with a higher A/M ((1.1–)1.2–2.5–3.8(–6)) and lower M/C ((0.9–)1.2–1.7–2.3(–2.7)). The presence of U. grandisora in the Philippines (Paguirigan et al. Reference Paguirigan, dela Cruz, Santiago, Gerlach and Aptroot2020) needs to be checked.

Usnea subdasaea Truong & P. Clerc, another neotropical species (widely distributed in South America), shares with U. paleograndisora the subcortical pigmentation and the same chemistry, but differs by having a thinner cortex ((3–)4.6–6.4%–8.2(–9.5), n = 14), by the more constricted lateral branches and by the minute, plane to stipitate soralia, rarely enlarging or fusing in irregular patches (Truong et al. Reference Truong, Bungartz and Clerc2011). The presence of U. subdasaea in the Philippines (Paguirigan et al. Reference Paguirigan, dela Cruz, Santiago, Gerlach and Aptroot2020) is dubious and needs to be checked.

Usnea sorediosula Motyka, an African species, also with a shrubby-sorediate thallus, with a red-orange subcortical pigment, differs from U. paleograndisora mainly by the absence of galbinic acid (protocetraric acid instead). Moreover, the lateral branches are not constricted, the soralia are punctiform (not large as in U. paleograndisora) and the cortex and central axis are thicker (8–10% and 40–50% respectively) (Nadel & Clerc Reference Nadel and Clerc2022). According to these authors, the occurrence of this species in the Philippines (Galinato et al. Reference Galinato, Baguino and Santiago2018) is dubious and should be checked. Furthermore, U. sorediosula is phylogenetically unrelated to U. paleograndisora (Fig. 2B & C).

Usnea bicolorata Motyka, another African species with a subcortical orange pigment, differs from U. paleograndisora mainly by the jet black-pigment and by the cornuta-tenuicorticata type of C/M/A (M/C = 4.4–6–7.8(–8)) (Nadel & Clerc Reference Nadel and Clerc2022).

Usnea dorogawensis Asahina differs from U. paleograndisora by the inflated branches, the concave soralia with granular soredia and few isidiomorphs, and by the presence of stictic and lobaric acids (Ohmura Reference Ohmura2001). For differences with U. spinulifera, see under that taxon.

Phylogenetic notes

There are three sequenced specimens from the Philippines (PU42, PU47, PU48) in a highly supported clade (BP = 100) (Fig. 2B). At first glance, U. paleograndisora is closely related to U. subdasaea, U. spinulifera and U. dasaea. However, their relationship is not supported by ITS phylogeny. The relationship with Usnea grandisora remains unknown until the type of this species is sequenced using NGS sequencing methodology.

Distribution

Usnea paleograndisora is known only from the Philippines, specifically from Mindanao (Marilog Forest Reserve). The species occurs on branches of trees (e.g. Medinilla sp., Pinus sp.).

Selected paratypes

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1200 m, 7.46245°N, 125.25488°E, on upwards trail, on thin branches, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/1018b (G), DNA-code: PU48; ibid., 1186 m, close to Mt Malambo, CMU nursery, anthropized environment, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/998b (BRIT), DNA-code: PU47.

Chemistry

1) Medulla K+ yellow; TLC: stictic, cryptostictic, menegazziaic, constictic and norstictic acids, ±fatty acid (n = 10). 2) Medulla K−, P+ red; TLC: protocetraric acid, ±fatty acid (n = 3). 3) Medulla K+ yellow turning red; TLC: salazinic, norstictic and ±protocetraric (trace) acids (n = 2). 4) Medulla K+ yellow turning red; TLC: salazinic and constictic acids (n = 1). 5) Medulla K+ yellow turning red; TLC: salazinic and diffractaic acid (n = 1). 6) Medulla K+ yellow turning red; TLC: barbatic, salazinic and 4-O-demethylbarbatic acids (n = 1).

Taxonomic notes

Usnea pectinata is treated in the broad sense; all specimens studied here shared a pendulous thallus with an almost solid, brown- to yellow-pigmented axis that only partially becomes fistulate. The lateral branches are often slightly broadened at the base, the cortex is moderately thick to thick on average (>9%), the medulla is thin to moderately thin (8–12%–19), and the axis is ±thick to thick (38.5–57.5%–71). The base is sometimes reddish tinged. The main branches can be decorticated like those in the type of U. pectinata (B 45057, B 56989 thallus number one) or more or less smooth, when irregular cracks are few or absent (B 56989 thallus number two). The presence of maculae on the cortex surface is often faint, being strong and punctiform in only one specimen (AG 627a). One herbarium specimen identified as Usnea angulata (B 600143608) corresponds to the extreme variability found in the Usnea pectinata aggr. in the Philippines: it is a coarse morphotype with numerous papillae occurring in ridges that develop longitudinally or at angles along the main branches, forming more or less angulate plates, and stictic acid as main medullary chemistry.

The Usnea pectinata aggr. is extremely variable in morphology (even if we looked at different branches in the same thallus) and also in chemistry; for this reason, this group should be reviewed using molecular techniques to verify the taxonomic value of the chemotypes and better understand the variation found in this species. Many names may be resurrected in the future and some cryptic species may be revealed.

Phylogenetic notes

Five sequenced specimens from the Philippines (PU15, PU17, PU29, PU32, PU49) clustered into a well-supported clade named Usnea pectinata aggregate (or Eumitria pectinata aggregate) (Fig. 2A). The sequenced specimens (YO 2989, YO 4373) correspond well to the type and Ohmura (Reference Ohmura2012) also mentioned decorticate main branches for Taiwan specimens. The five sequenced specimens from the Philippines do not have really decorticated main branches as shown by Ohmura (Reference Ohmura2012, fig. 24C) but annular cracks in the main branches which can present medullary tissue in between when well developed (very visible in PU49). These specimens clustered within a small ‘Asian subclade’. Moreover, the sequenced specimens do not contain stictic acid as is present in U. pectinata. Instead, the chemistry of this ‘small Asian clade’ is also surprising: protocetraric (with or without diffractaic) and salazinic plus diffractaic acids.

From all specimens with stictic acid analyzed from the Philippines, we obtained only one sequence (PU17). Its position is not phylogenetically close to the Asian specimens of U. pectinata (YO 2989, YO 4373 and Li308). The long branches and a lack of support indicate that it is not conspecific with these Asian specimens or those from Africa (Fig. 2A). It could represent Usnea schadenbergiana, the older name for the stictic acid chemotype. However, we refrain from using this name here due to the fact that morphologically we cannot separate the samples of the stictic acid chemotype found in the Philippines from those found in Japan and Taiwan. The phylogeny of the U. pectinata clade is quite complicated, with several lineages in Africa and Asia (Temu et al. Reference Temu, Clerc, Tibell, Tibuhwa and Tibell2019; Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020; Nadel & Clerc Reference Nadel and Clerc2022; Temu et al. Reference Temu, Clerc, Nadel, Tibell, Tibuhwa and Tibell2022), and we may be facing a complex of cryptic species here but more studies are required before making a decision. A deeper study with molecular tools and taking into account all the species and geographical range is necessary to understand the taxonomic boundaries in this complex aggregate.

Distribution

Usnea pectinata is widely found in the Philippines. It has been reported from the islands of Luzon and Mindanao (Bukidnon Province) by Herre (Reference Herre1963), Gruezo (Reference Gruezo1979), Sipman et al. (Reference Sipman, Diederich and Aptroot2013) and Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017). It is recorded here for the first time from Negros and Palawan. The specimens analyzed here occur mainly in secondary forest, planted edible ferns and coconut palms, over coconut palm bark.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1227 m, 7.45938°N, 125.25106°E, anthropized environment, on Pinus, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/996c (G), DNA-code: PU17; ibid., 1095 m, open road, disturbed, close to the main road near Lawi Lawi Resort, 2019, A. Gerlach (with Dal Forno & J. Nobleza) AG 2019/979 (BRIT), DNA-code: PU15. Negros: Negros Oriental, Dumaguete City, Balinsasayao Twin Lakes Natural Park, 893 m, 9.35281°N, 123.18253°E, on fallen branches, 2019, A. Gerlach (with A. D. Nietes) AG 2019/627 (BRIT); Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, fernery behind restaurant, 909 m, 9.36083°N, 123.17846°E, on coconut tree, 2019, M. Dal Forno (with A. Gerlach & A. D. Nietes) 3482 (BRIT), DNA-code: PU32, 3497 (G), DNA-code: PU29; ibid., on coconut palm, 2019, A. Gerlach (with A. D. Nietes) AG 2019/636a (G), DNA-code: PU49. Palawan: Distr. Brooke's Point, along trail from Macagua, at E-foot, to summit of Mt Mantalingahan, 1100 m, in mossy primary forest on ridge, 1991, H. Sipman & B. Tan 29976 (B 83618).

Taxonomic notes

Usnea pygmoidea belongs to the U. cornuta aggregate; for a full description of U. pygmoidea, see Ohmura (Reference Ohmura2001, Reference Ohmura2012). It is recognized by the inflated branches which are glossy on the surface, the stipitate and irregularly elongated soralia, the presence of granular soredia together with isidiomorphs (Fig. 7B–D), and the presence of salazinic or stictic acids as major substances (Ohmura Reference Ohmura2001). The cortex is thin to moderately thin (3–8%), the medulla lax, moderately thick to thick (26–40%), and the central axis thin (13–33%) (Ohmura Reference Ohmura2001). The specimen analyzed here has a similar morphology, anatomy (%C/M/A: 4.5/34.5/22) and chemistry (stictic acid as main medullary compound), differing from U. pygmoidea by its black base (Fig. 7A) and by its ITS sequence. Usnea pygmoidea (sorediate) is considered as the secondary species of U. orientalis Motyka (apothecia) in the species pair concept (Shen et al. Reference Shen, Hsieh, Yeh and Hung2012). In our phylogenetic analysis, their relationship is unresolved (Fig. 2C).

Figure 7. Usnea cf. pygmoidea (PU40). A, black base. B, section of branch. C, general aspect of the thallus showing many soralia, isidiomorphs and isidiofibrils. D, stipitate and irregular elongated soralia. Scales: A & D = 0.5 mm; B & C = 1 mm. In colour online.

Phylogenetic notes

The specimen PU40 is a singleton close to Usnea articulata (BP = 89; Fig. 2E), and not related to U. pygmoidea from Japan (YO 3144c, YO 2736) (Fig. 2C). The specimen studied here probably belongs to a new taxon, despite its aforementioned phenotypic similarities.

Distribution

Usnea pygmoidea occurs in Japan and Taiwan (Ohmura Reference Ohmura2001). It was reported for the Philippines in Mindanao by Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017) and Galinato et al. (Reference Galinato, Baguino and Santiago2018).

Specimen examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1202 m, 7.45392°N, 125.24509°E, close to the main road to the Lawi Lawi Resort, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/909 (G), DNA-code: PU40.

Chemistry

Medulla K+ yellow. TLC: stictic, cryptostictic, menegazziaic, constictic and norstictic acids (n = 5).

Taxonomic notes

Usnea rubicunda can be easily recognized by the erect-shrubby to subpendulous thallus, with lateral branches cylindrical at ramification point, by the thick and shiny cortex, with a red pigment which is often diffuse (homogeneous) in the whole thallus, the stipitate and rounded soralia with many isidiomorphs, and by the presence of stictic acid. Usnea rubrotincta is a similar species, also red-pigmented in the cortex. It differs mainly by the morphology of the soralia and the subterminal and terminal branches (Ohmura Reference Ohmura2008) and by the chemistry (salazinic acid instead of stictic), although this last character might not have the same value in different parts of the world. In Japan, for instance, it clearly separates both species but not in Taiwan (Y. Ohmura, personal communication). The pattern of pigmentation in this species is also quite different from the one in U. rubrotincta (see under U. rubrotincta for more details).

Phylogenetic notes

Three ITS sequences from the Philippines (PU27, PU51, PU53) clustered into two phylogenetically close clades: rubicunda-1, with one specimen from Taiwan and rubicunda-2 with one specimen from Japan (Fig. 2E). Usnea rubicunda is a polyphyletic taxon (Truong et al. Reference Truong, Divakar, Yahr, Crespo and Clerc2013a; Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020). Given that the type of U. rubicunda is from Great Britain (Stirton Reference Stirton1881), we follow Lücking et al. (Reference Lücking, Nadel, Araujo and Gerlach2020) and consider the cluster including all specimens from Great Britain and several from South America as U. rubicunda s. str. (Fig. 2E).

Distribution

Usnea rubicunda was reported from the Philippines for Luzon (Benguet, Ifugao, Kalinga, Nueva Vizcaya) and Mindanao (Bukidnon) Islands by Herre (Reference Herre1963), Gruezo (Reference Gruezo1979), Bawingan et al. (Reference Bawingan, Flores, Lardizabal and Rosuman2000), Santiago et al. (Reference Santiago, Sangvichien, Boonpragob and dela Cruz2013) and Galinato et al. (Reference Galinato, Mangubat, Leonor, Cababa, Cipriano and Santiago2017). It is the first record for Negros.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1188 m, 7.45960°N, 125.24522°E, disturbed forest, abandoned house, on Pinus sp., 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/950b (G), DNA-code: PU53. Negros: Negros Oriental, Dumaguete City, Santa Catalina, San Pedro, Cuernos de Negros, 1337 m, 9.24099°N, 123.11667°E, open area close to camping site, from the canopy of trees, 2019, A. Gerlach (with M. Dal Forno & A. D. Nietes) AG 2019/847 (BRIT, PNH), DNA-code: PU51; Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, fernery behind restaurant, 909 m, 9.36083°N, 123.17846°E, planted edible ferns and coconut palms, on coconut tree, 2019, M. Dal Forno (with A. Gerlach & A. D. Nietes) 3494 (BRIT), DNA-code: PU27.

Chemistry

Medulla K+ yellow turning red. TLC: salazinic, norstictic and protocetraric (trace) acids (n = 3).

Taxonomic notes

Usnea rubrotincta can be recognized by the shiny and thick cortex (10–12%), the moderately thick central axis (20–47%), the spotted red pigmentation pattern at the cortex surface, and by the soralia that occur mainly in the fibrils.

Phylogenetic notes

We have only one sequenced specimen (PU06) that clustered within an Usnea rubrotincta clade from Japan and Taiwan with good support (BP = 96) (Fig. 2E). Lücking et al. (Reference Lücking, Nadel, Araujo and Gerlach2020), with an expanded ITS global tree, suggested that Usnea rubrotincta (type from Madeira) could represent two different species. Again, to clarify the position of Usnea rubrotincta the type should be sequenced and further analyses using multilocus data should be performed.

Distribution

The species was reported for the Philippines from the islands of Luzon and Mindanao (Bukidnon) by Herre (Reference Herre1963), Gruezo (Reference Gruezo1979) and Timbreza et al. (Reference Timbreza, Delos Reyes, Flores, Perez, Stockel and Santiago2017).

Specimen examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, after the first cave, edge of a forest close to the river, 1169 m, 7.46024°N, 125.25790°E, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/891b (BRIT), DNA-code: PU06.

Chemistry

Medulla K+ yellow turning dark red, P+ orange-red. TLC (n = 1): salazinic, norstictic and galbinic acids.

Taxonomic notes

Based mainly on the galbinic acid chemistry and the presence of densely distributed spinulose fibrils, Usnea spinulifera was synonymized with U. dasaea Stirt. by Clerc & Herrera-Campos (Reference Clerc and Herrera-Campos1997). However, phylogenetic evidence (Fig. 2B) coupled with detailed morphological and anatomical investigations make the clear separation of both taxa possible. Usnea spinulifera differs from U. dasaea mainly by the soralia that become enlarged, especially at the apices of branches where they fuse and build whitish club-like thick and sometimes spinulose (isidiomorphs) consoralia ending abruptly at the branches. Specimens from the Philippines have an inconspicuous, irregularly distributed light orangish subcortical pigmentation. However, the type specimen from Brazil and all specimens collected in Brazil and identified as U. spinulifera lack an orange subcortical pigmentation. This variability supports the observation that in the U. dasaea aggr. the subcortical pigment might not be a constant character (Gerlach et al. Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019).

Phylogenetic notes

Four specimens from the Philippines (PU20, PU05, PU08, PU39) clustered in a well-supported clade (BP = 100) with two specimens from Brazil (39BR, 33BR). Usnea dasaea (type from Portugal) presents a wide list of synonyms, including U. spinulifera (Clerc & Herrera-Campos (Reference Clerc and Herrera-Campos1997). Gerlach et al. (Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019) suggested for the first time that U. dasaea is polyphyletic and only two ITS sequences (JN086283 and JN086284) would indicate the phylogenetic position of U. dasaea; however, the low quality of these sequences make the topology unreliable (Lücking et al. Reference Lücking, Nadel, Araujo and Gerlach2020). Recently a new ITS sequence from Portugal was generated, indicating the probable identity of Usnea dasaea s. str. Based on the chemistry, the morphology of soralia and the presence of Brazilian specimens (Fig. 2B), we decided to name this clade, containing the four specimens from the Philippines, U. spinulifera (Fig. 8).

Distribution

So far, Usnea spinulifera is found to occur only in Brazil, Costa Rica and the Philippines.

Selected specimens examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1169 m, 7.46024°N, 125.25790°E, after the first cave, edge of a forest close to the river, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/891a (G), DNA-code: PU05; ibid., 1227 m, on the new Baganinhan road, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/893c (BRIT), DNA-code: PU39; ibid., 1095 m, 7.45788°N, 125.23925°E, open road, disturbed, close to the main road near Lawi Lawi Resort, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/969a, b (BRIT, G), DNA-code: PU08; Lawi Lawi Resort, Arakan, Datu Ladayon, Mt Malambo surroundings, close to CMU nursery and private property near Bussay Waterfall, 1185 m, 7.4815°N, 125.26204°E, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG19/1003 (G), DNA-code: PU20.

Taxonomic notes

The specimen identified is similar to Usnea subflammea, meaning it has an erect-shrubby sorediate thallus with a thick (12.5%), matt cortex and pruinose appearance, a thin and compact medulla (17%) and ±thin axis (40%), with tubercles; lateral branches not constricted, main branches cylindrical and terete. The base is brownish and annulated. Soralia are mainly minute, sometimes large. We found only one juvenile thallus with these morphological characters, which is not enough to describe it as new to science.

Phylogenetic notes

We obtained one sequence (PU43) which clustered with Usnea subflammea from Brazil (65BR, 66BR) but without support (Fig. 2B). One ITS sequence of Usnea subflammea from the Canary Islands (type locality; Clerc Reference Clerc2006) clustered outside this group which suggests that the lineage found in the Philippines and Brazil could be a different, unnamed species (Gerlach et al. Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019, fig. 1: black stars).

Specimen examined

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1215 m, 7.46423°N, 125.25430°E, trail with native plants close to a new road, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/1008c (BRIT), DNA-code: PU43.

Chemistry

Medulla K−, Pd+ red. TLC (n = 1): protocetraric acid.

Taxonomic notes

The specimen collected in the Philippines is damaged and necrotic (collected on a fallen tree). However, the presence of protocetraric acid in the medulla, the vitreous and thick cortex, the unpigmented basal part and the morphology of soralia leave no doubt about its identity.

Phylogenetic notes

DNA from the small collected specimen was not extracted. In Gerlach et al. (Reference Gerlach, Toprak, Naciri, Caviró, Borges da Silveira and Clerc2019), U. subscabrosa was part of clade Usnea-1, as sister species to an unknown Brazilian species (Usnea sp. 4, with galbinic acid).

Distribution

Until now, Usnea subscabrosa was found to occur in south-western Europe, Macaronesia, and Northeastern America (Clerc Reference Clerc1992, fig. 5), Mexico (Herrera-Campos et al. Reference Herrera-Campos, Clerc and Nash1998; Clerc Reference Clerc, Nash, Gries and Bungartz2007) and South America (Truong et al. Reference Truong, Rodriguez and Clerc2013b). In Asia, it was reported for the north Philippines (Luzon) for the first time by Bawingan et al. (Reference Bawingan, Flores, Lardizabal and Rosuman2000). This is the first record for the southern Philippines.

Specimen examined

Philippines: Negros: Negros Oriental, Dumaguete City, Taclobo, Larena Drive, Balinsasayao Twin Lakes Natural Park, fallen Agathis tree, 1058 m, 9.36111°N, 123.175°E, on fallen tree trunk, 2019, M. Dal Forno (with J. Shevock & D. Salas) 3438b (BRIT).

Chemistry

1) Medulla K+ yellow, turning slowly orangish, P+ orange; TLC (n = 6): stictic, constictic, cryptostictic, menegazziaic, ±norstictic (weak when present) acids. 2) Medulla K+ yellow turning red, P+ orange-red; TLC (n = 1): salazinic and norstictic acids.

Etymology

This taxon is named in honour of our esteemed colleague and friend Yoshihito Ohmura for his major contribution to the study of the genus Usnea in Asia.

Taxonomic notes

Usnea yoshihitoi is characterized by the shrubby to subpendent thallus with strongly irregular branches in transversal section, with inflated, often flattened segments, the punctiform soralia that are not aggregating, the thin, glossy, often perforated cortex, the thick medulla with densely and evenly arranged, not conglutinated, hyphae (Fig. 9A–E), and the presence mainly of the stictic acid group, more rarely salazinic and norstictic acids as main medullary compounds. Perforations of the cortex are sometimes rare and difficult to find, but were always found in the seven specimens collected. The soralia are sometimes not well developed or not developed at all. In this case, the fibercles remain as minute, whitish pseudocyphellae. The presence of tiny fibrils looking like isidiofibrils but developing in the cortex is variable. Isidiomorphs can be absent to numerous. Usnea yoshihitoi is the sister clade of U. bismolliuscula (Fig. 2D). Both species share a unique character in the genus Usnea, the presence of a perforated cortex. Usnea yoshihitoi differs from U. bismolliuscula by the denser medulla with hyphae that are not conglutinated. Furthermore, the soralia of U. yoshihitoi remain minute and distinct whereas in mature thalli of U. bismolliuscula the soralia enlarge (>1/2 branch diameter) and aggregate with other soralia and might finally fuse together to form larger irregular or longitudinally stretched consoralia. Young thalli of U. yoshihitoi without perforated thalli might be difficult to separate from other species with irregular branches and constricted lateral branches, and DNA-barcoding might be necessary here.

Phylogenetic notes

Five specimens (PU07, PU14, PU16, PU25, PU45) clustered inside a well-supported clade close to Usnea beckeri P. Clerc & Nadel, a pendulous-fertile species recently described from Africa (Nadel & Clerc Reference Nadel and Clerc2022) (Fig. 2D).

Distribution

Corticolous, found so far only in the Philippines, mainly in Mindanao in tropical lowland rainforest in disturbed or undisturbed habitats.

Selected paratypes

Philippines: Mindanao: Davao del Sur, Marilog District, Davao City, Baganihan, Marilog Forest Reserve, 1162 m, 7.45392°N, 125.24509°E, disturbed forest, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/931 (TNS), DNA-code: PU16; ibid., after the first cave, edge of a forest close to the river, 1169 m, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/891c (G), DNA-code: PU07; ibid., 1131 m, beginning of trail to Epol Waterfall, part way down, on Pinus sp., 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/957c (G), DNA-code: PU14; Mt Malambo, open area with Pinus sp., 1279 m, 2019, A. Gerlach (with M. Dal Forno & J. Nobleza) AG 2019/992a (BRIT), DNA-code: PU45. Negros: Negros Oriental, Dumaguete City, Santa Catalina, San Pedro, Cuernos de Negros, 1324 m, 9.24092°N, 123.11626°E, tropical lowland rainforest, 2019, A. Gerlach (with M. Dal Forno & A. D. Nietes) AG 2019/852c (G).