86 American Midland Naturalist Monograph No. 6 



A genus of 300 species distributed over the whole earth, on soil and rocks, 

 many of these species are poorly defined and probably synonymous; about 20 

 species in North America; only two species definitely known from our region. 



Key to the Species 



A. Perichaetial leaves high-convolute-sheathing: seta yellow or later reddish 



3. B. convoluta 



A. Perichaetial leaves not as above: seta red or brown B 



B. Stem-leaves obtuse, costa shortly mucronate-excurrent 2. B. unguiculata 



B. Stem-leaves acute, costa not mucronate-excurrent C 



C. Costa .070 mm wide at base and tapering gradually; leaves widely spreading or but 



little recurved 1. B. acuminata 



C. Costa .050 mm wide at base and of equal breadth to the middle; leaves strongly 



recurved or squarrose (B. reflexa Bridel ) 



1. Barbula acuminata Hedwig 



{B. fallax Hedwig) 



Loosely and widely cespitose, brownish dull green: stems fastigiately 

 branched, slender, 1-5 cm high; leaves somewhat distant, recurved-spreading 

 or arcuate, appressed and slightly twisted when dry, lanceolate-acuminate from 

 the base, the base ovate, the leaves carinate and often faintly plicate below, 

 the margin revolute in the lower half at least, entire; costa strong, ending in 

 the apex; upper leaf-cells small, rounded to hexagonal, incrassate, strongly 

 papillose, gradually larger below, and at the lowest part of the base a few 

 elongate-rectangular and pellucid: seta reddish, capsule brownish, long-ovoid 

 to sub-cylindric, mostly symmetric and erect; lid long, often as long as the 

 urn, acutely rostrate-subulate; peristome-teeth reddish, long, filiform, dex- 

 trorsely much twisted, united at base into a low membrane; annulus none; 

 spores mature from late fall to spring: dioicous. 



On moist earth, rocks, walls, etc., usually on calcareous substrata, in 

 Europe, Asia, northern Africa, and, in North America from the Arctic region 

 south to Virginia and Iowa. To be expected in northern Pennsylvania. 



2. Barbula unguiculata [Hudson] Hedwig 

 Plate XVII 

 Densely cespitose, yellowish-green: stems erect, somewhat branching, usu- 

 ally about 1 cm high; leaves about 2 mm long, erect-spreading, somewhat 

 recurved, when dry spirally imbricate and twisted, oblong-lanceolate, sometimes 

 lingulate, obtuse, mucronate, entire, the margin recurved below, plane above; 

 costa strong, excurrent and thus forming the rounded mucro; upper leaf-cells 

 small, about .008-.010 mm, rounded-quadrate, incrassate, strongly papillose, 

 obscure, the basal elongate-rectangular, yellowish-pellucid to more or less hya- 

 line, the marginal not different; perichaetial leaves longer and more erect: 

 seta erect, castaneous, lustrous, about I cm high, when dry sinistrorse; capsule 

 oblong-cylindric, deep-castaneous, the urn about 1.8 mm long, erect, exannu- 

 late, rather smooth when dry and empty; lid about one-third as long as urn, 

 conic-rostrate, slightly curved or straight; the 16 peristome-teeth castaneous, 

 pellucid, papillose, cleft to the base into 32 filiform divisions, from a narrow 



