218 A MANUAL OF MOSSES 



fenestrate, rarely cleft the whole length, cilia mostly none; lid 

 conic, erectly to obliquely rostrate; calyptra mitrate to cucul- 

 late, mostly hirsute; spores of varying size. 



A large family, occurring mainly on trees in warmer re- 

 gions, often forming a conspicuous part of the vegetation; 51 

 genera, of which but three occur in our region. 



Key to the Genera. 



a. Secondary stems flattened, ascending or pendent; leaves mostly 



conspicuously unsymmetric. b. 



a. Secondary steps mostly erect and branched in a tree-like manner; 

 leaves only slightly unsymmetric. 3. Thamnium. 



b. Exannulate; basal membrane of inner peristome low, cilia 



none, segments narrowly linear. 1. Neckera. 



b. Annulus 2-seriate; basal membrane conspicuous, cilia rudi- 

 mentary and soon disappearing or well-developed, segments 

 about as broad as teeth. 2. Homalia. 



1. NECKERA Hedwig. 



Autoicous or dioicous, rarely synoicous : mostly more or 

 less robust, cespitose, green to yellowish or brownish, some- 

 what lustrous : primary stems often stoloniferous, paraphyllia 

 mostly none ; leaves on the filiform shoots small, ecostate, sym- 

 metric, concave; normal leaves either 8-seriate, the dorsal and 

 ventral alternately turned to the side, the lateral spreading, 

 or 4-seriate, the dorsal and yentral series lacking, leaves plane, 

 unsymmetric, rugose, more or less spatulate from a broader and 

 shortly decurrent base, acute to obtuse or truncate ; costa vari- 

 ous; upper leaf-cells rounded to rhombic, the lower linear, the 

 alar differentiated, small and quadrate ; perichaetial leaves high- 

 sheathing, narrow, long-acuminate : capsule oval or elliptic, im- 

 mersed to exserted ; annulus none ; peristome double, inserted 

 far back; peristome-teeth lance-linear, often basally striate, 

 low-trabeculate, sometimes split along the divisural; basal 

 membrane mostly very low ; cilia none ; calyptra mostly cucul- 

 late and with erect hairs ; spores medium, mostly brownish, 

 papillose. 



A widely distributed genus of about 160 species ; about 20 

 species in North America; two species in our region. 



Key to the Species. 



a. Leaves narrower, acute to acuminate; capsule at least partly im- 

 mersed. 1. N. pennata. 

 a. Leaves rounded and abruptly apiculate; capsules exserted. 



2. N. complanata. 



1. Neckera pennata [Linnaeus] Hedwig. 



(Fonfinalis pennata Linnaeus). 



Large, with primary stems creeping, often stoloniferous, 



the secondary stems 6 to 8 or 10 cm. long, erect, pinnate or 



nearly simple; leaves lance-ovate, acute to acuminate, more 



