Constant species

Poa annua, Sagina procumbens.

Physiognomy

The Sagino-Bryetum is a species-poor but highly distinctive community in which cushions of Bryum argenteum and small scattered individuals of Poa annua and Sagina procumbens form the most consistent features, often disposed in striking patterns between cobble stones and pavement cracks. No other species are frequent throughout but Capsella bursa-pastoris, Plantago major and Agrostis stolonifera are occasional and Stellaria media and Medicago lupulina can sometimes be seen. Mosses like Bryum bicolor and Schistidium apocarpum occur as scarce associates of B. argenteum.

Sub-communities

Typical sub-community. There are no additional consistent features here but Arenaria serpyllifolia, Juncus bufonius and Polygonum aviculare occur occasionally with Ceratodon purpureus. Sagina apetala and S. subulata can sometimes be found among the S. procumbens.

Lolium perenne-Chamomilla suaveolens sub-community.

The vegetation in this sub-community is richer and more extensive in cover than above, with L. perenne and C. suaveolens both constant, Plantago major and Agrostis stolonifera frequent, Dactylis glomerata, P. major and Agrostis stolonifera frequent,and Ranunculus repens occasional.

Habitat

The Sagino-Bryetum is a very widespread community of crevices between cobble stones and paving slabs in streets, on pavements and in courtyards in urban and suburban areas and around farm and country dwellings, where there is trampling by pedestrians or light vehicle traffic.