100 HYPNACEAE 



Key 



i — Leaves with a single long strong costa 3 



Leaves ecostate or with costa short and double 2 



2 — Stems green when fully grown; ends of stems and branches cuspidate 



with the convolute apical leaves; plants of wet places ciispidatum 



Stems red; plants of dryer situations. Very common Schreberi 



3 — Branches few; enlarged and decurrent angular cells gradually grading 



into the others cordifolium 



Pinnately and rather regularly branched; enlarged and swollen cells 

 of auricles abruptly differentiated from the others giganteum 



C. cordifolium (Hedw.) Kindb. Common in wet swampy- 

 places. Spring-summer. 



C. cuspidatum (L.) Kindb. "Bogs, common," Muse. App. 

 444; Richmond Hill, L. Id.; Closter and Clifton, N. J.; Yonkers. 



C. giganteum (Schimp.) Kindb. Danbury, Ct., Nichols, 

 Bx! Summer. 



C. Schreberi (Willd.) Grout. On ground in woods, common, 

 except on L. Id. and S. Id. Reported from Bath and New 

 Lots, L. Id. and Giffords, S. Id. Summer. 



Subfamily Hypneae 



Central strand lacking or thin and few-celled; leaves often 

 strongly falcate-secund, without costa or with costa short and 

 double (except Hygrohypnum sp.) ; leaf cells Hnear-flexuose in 

 most species (rhomboidal to linear-rhomboidal in Amblystegiella) ; 

 capsules oblong to cylindric, typically inclined to horizontal, 

 and unsymmetric to strongly curved, but nearly erect and sym- 

 metric in some few species; peristome perfect except in some of 

 the species with erect capsules. This subfamily differs from the 

 last in the slightly developed costa and longer leaf cells. Hygro- 

 hypnum is a connecting link. 



Key to the Genera 



1 — Branching often regularly pinnate to plumose; leaves strongly fal- 

 cate-secund; costa short and double or lacking; alar cells usually 



strongly differentiated Hypnum 



Branching irregular; leaves apparently in two rows, complanate, 



costa as in Hypnum Plagiothecium and Hypnum pratense 



Leaves neither complanate nor strongly secund, or if strongly secund, 

 with a strongly marked costa 2 



