Constant species

Elymus repens, Matricaria perforata, Poa annua.

Physiognomy

The Poa annua-Matricaria perforata community includes coarse weedy vegetation with a variety of more ephemeral herbs, some small, others more bulky, and some perennial grasses. Poa annua is the commonest grass but Elymus repens and Agrostis stolonifera are frequent in many of the sub-communities and Lolium perenne is also often prominent. Matricaria perforata and, somewhat less commonly, Chamomilla suaveolens, are characteristic, too, with Polygonum aviculare. No other associates of the community as a whole are frequent throughout but Capsella bursa-pastoris, Holcus lanatus, Chenopodium album, Rumex obtusifolius and R. crispus occur commonly in several subcommunities. Plantago lanceolata, Taraxacum officinale agg., Stellaria media, Sinapis arvensis and Anagallis arvensis are scarce throughout. Bryophytes are sparse but Pottia truncata, Funaria hugrometrica, Brvum argenteum, B. caespiticium and B. microerythrocarpon can occasionally be seen, sometimes in great abundance.

Sub-communities

Senecio squalidus-Epilobium angustifolium sub-community. Perennial grasses are very sparse here and mixtures of Poa annua and Matricaria perforata with Chamomilla suaveolens and Polygonum aviculare form the bulk of the cover with Senecio squalidus and Epilobium angustifolium frequent preferentials. Scattered plants of Tussilago farfara and Reseda lutea can sometimes be seen and carpets of Funaria hygrometrica and Bryum spp. are occasionally very extensive.

Lolium perenne-Capsella bursa-pastoris sub-community.

Lolium perenne, Holcus lanatus and Poa trivialis are all frequent in this sub-community along with Capsella bursa-pastoris and Polygonum persicaria. Papaver rhoeas, Lapsana communis, Chenopodium album, Plantago major, Atriplex prostrata, Rumex obtusifolius and Cirsium arvense occur occasionally.