64 BRYACEAE 



Family 20. BRYACEAE 



For the most part large conspicuous mosses growing in close 

 tufts, or loosely aggregated, or scattered; some forms spreading 

 by stolons have the habit of sterile pleurocarpous mosses. 

 Leaves usually large, smaller below and increasing in size up- 

 ward to the upper, which often form a distinct comal tuft, all 

 supported by a strong costa which extends nearly to the apex, 

 or may be somewhat excurrent, and in many species by a 

 thickened border of narrower elongated cells. Leaf cells large 

 and comparatively thin-walled, short and broad in the Mnieae, 

 longer and narrower in the Bryeae. A few species are small 

 with small leaves, but with the characteristic sporophyte of the 

 family. Calyptra cucullate. Capsules proportionately large, 

 pendent or drooping, often light-colored, not striate or plicate 

 when dry, usually symmetric. Peristome characteristically 

 perfect, cilia sometimes rudimentary or lacking. 



Key to Subfamilies 



Plants larger; leaf cells not more than twice as long as broad; cilia not 



appendiculate (Rhodobryum will be sought here) Mnieae 



Plants usually smaller; leaf cells more than twice as long as broad; cilia 



often appendiculate. occasionally wanting Bryeae 



Subfamily i. Bryeae 



1 — Plants large, with the habit of a large Mnium. from creeping, rhiz- 

 ome-like stolons; upper leaves in rosettes 12-20 mm. across; capsules 



clustered Rhodobryu m 



Plants smaller, without rhizomelike stolons 2 



2 — Leaves ovate to ovate-lanceolate; leaf cells rhombic to rhombic- 

 hexagonal, never linear except at margins 4 



Leaves linear-lanceolate or narrower (the lower are often broader); 



leaf cells narrowly rhombic to linear 3 



3 — Leaves linear from a broader base, hairlike; cilia appendiculate. 



Leptobryum 

 Upper leaves linear-lanceolate; cilia not appendiculate, sometimes 



wanting Pohlia 



4 — Leaves not bordered; dioicous; annulus lacking; stomata immersed; 

 leaf cells long and lax; growing in water or very wet places. 



Mmobryum 

 Leaves often bordered; inflorescence various; stomata superficial; 

 leaf cells usuallv shorter Brvum 



