During a recent expedition of the Eurasian Dry Grassland Group in the steppes of southern Ukraine, we discovered on sand dunes a new sterile crustose aspicilioid lichen with rhizomorphs. It is described here as new to science under the name Circinaria ucrainica (Megasporaceae). The new combination Circinaria reptans (Looman) Khodos. & Darmostuk is also proposed. Circinaria ucrainica is characterized by small grey areoles with a net of dark grey to brownish spicate prothalline tips and pale rhizomorphs. According to the phylogenetic analysis, the new species is closely related to the terricolous Circinaria reptans, but the latter has thicker rhizomorphs of 200–400 μm diameter, finely developed areoles and lacks spicate prothalline tips. Furthermore, we discuss the differences between the new species and other morphologically similar species with rhizomorphs, such as Aspicilia spicata, Circinaria crespiana and C. reptans. The ecological characters of soil and vegetation, including vascular plants, bryophytes and lichens, are provided for the habitat of C. ucrainica.

Endozoochorous dispersal of seeds by livestock has long attracted the attention of grassland scientists. However, little is known about seed dispersal after ingestion by Kazakh sheep on dry grasslands in the Tianshan Mountains. The objective of this experiment was to learn more about the recovery and germinability of seeds from 17 plant species after either actual or simulated ingestion (i.e. insertion through a rumen fistula) by Kazakh sheep. The passage time of seeds through the sheep gut ranged from 12 to 96 h. More than 80% of all recovered seeds were defecated 24–48 h after ingestion. The mean retention time of seeds in the gut ranged from 27.3 to 42.2 h. Seed recovery percentage ranged between 12.6 and 17.6% for leguminous species and between 0.8 and 3.2% for gramineous species. Seed recovery percentage was positively correlated with seed mass, but negatively correlated with seed shape. The germination percentages of the gramineous species were greater in the non-ingested treatment (66–98%) than in the simulated ingestion treatment (3–10%). In contrast, for leguminous species, seed germination percentages were greater in the simulated ingestion treatment (23–70%) than in the non-ingested one (5–12%). Seed germination percentage after simulated ingestion was positively correlated with seed mass, but negatively correlated with seed shape. In conclusion, leguminous seeds were more likely than gramineous ones to pass through the gut of Kazakh sheep and then germinate. Free-ranging Kazakh sheep can contribute to the spread of plant species, especially leguminous species, in the Tianshan Mountains.