OF WESTERN PENNSYLVANIA 273 



tome-teeth narrowly lance-ovate, basally confluent, yellowish, 

 bordered, dorsally cross-striate, above pale and papillose, dense- 

 ly trabecnlate below ; inner peristome pale or yellow, basal 

 membrane high, segments entire or but slightly split, cilia rare- 

 ly 1-3 and complete, mostly solitary and rudimentary or none, 

 non-appendiculate ; lid high-convex, obtuse to acute ; spores 

 small. 



A genus of 8 species, confined to the Northern Hemisphere, 

 occurring on trees and rocks ; 5 species in North America ; two 

 species occurring in our range. 



Key to the Species. 



a. Inner perichsetial leaves irregularly toothed above; leaves not nar- 

 rowed to insertion: alar cells longer than broad. 



1. A. iniiuitisshiia. 



a. Inner perichaetial leaves entire; leaves narrowed to the insertion; 

 alar cells quadrate. 2. A. confervoides. 



1. Amblystegiella minutissima (Sullivant and Lesquereux) 



Nichols. 



(Hypnnm minutissimum Sullivant and Lesquereux; Auibly- 

 stegiiun niinutissintum Jaeger). 



Minute, pale green : stems prostrate, short, up to about 1 

 cm. long, with radicles in fascicles, the branches occurring sub- 

 pinnately and spreading to erect ; leaves loose, narrowly tri- 

 angular-lanceolate, broadest and not narrowed at base, 3-4 mm. 

 long, more or less serrulate, ecostate or very faintly marked 

 with stride; leaf-cells large, oblong, about 4-8:1, the marginal 

 alar cells about 2:1 ; capsule minute, about 0.5 mm. long, ovoid, 

 symmetric or slightly curved, constricted below the mouth and 

 turbinate when dry and empty, thin-walled, yellowish ; seta 

 slender, 4 or 5 mm. long; teeth yellowish, hyaline-bordered; 

 cilia as long as segments and 1 or 2 in number ; annulus 2- 

 seriate, persistent ; lid conic, apiculate-rostrate, about one-half 

 as long as urn. 



On rocks and stones in shaded ravines, said to prefer lime- 

 stone, from New Jersey and Pennsylvania westward to Illinois, 

 Ontario, the Rocky Mountains and British Columbia. Rare in 

 our region. 



Huntingdon : Alexandria. T. C. Porter. ( Porter's Cata- 

 logue). 



2. Amblystegiella conferva (Schwaegrichen) New Combination. 



(Hypnnm confcri'oidcs Bridel ; A. confervoides Loeske; Hypnnm 

 conferva Schwaegrichen) . 



Dark green, minute ; stems irregularly branching, about 

 0.5-1.0 cm. long; leaves very small, about 0.2-0.4 mm. long, 

 rather distant, more or less appressed both wet and dry, 

 entire or almost so, ovate, acuminate, ecostate; leaf-cells irre- 



