OF WESTERN' PENNSYLVANIA 115 



Key to the Species. 



a. Autoicous: leaf-margins plane: seta l.S mm. long or less; beak of 

 operculum shorter than radius of capsule. 1. A. lapponicum. 



a. Dioicous: leaf-margins recurved below: seta about 3 mm. long; 

 beak of operculum longer than radius of capsule. 



2. A. mougeotii. 



1. Amphidium lapponicum (Hedwig) Schimper. 

 (Anictangium lapponicum Hedwig; Zygodoii lapponicus Bryolo- 



gia Europtea). 



Densely cespitose, dark ojive-green above, blackish below : 

 stems dichotomously branching, usually 1-3 cm. high ; leaves 

 flexuGus-spreading, lance-oblong to lance-linear, 1.5-2.0 mm. 

 long, margins plane, acute, crisped when dry ; costa strong, 

 ending below apex; basal cells large, thin-walled, pellucid to 

 hyaline, the upper small, quadrate-hexagonal, rather obscure, 

 incrassate, papillose ; perichsetial leaves sheathing : seta very 

 short, usually not over 1.5 mm.; capsule oval with distinct 

 collum about as long as sporangium, partially immersed, 

 brownish, when dry constricted below mouth, urceolate, with 

 8 reddish striae, the mouth forming a deep red, thickened rim ; 

 no peristome ; lid red, lustrous, small, low-conic, obliquely 

 rostellate, the length of the beak not more than one-half the 

 diameter of the capsule ; calyptra cucullate, small, reaching 

 about half-way down the urn, brownish ; spores mature in 

 early summer : autoicous, the antheridial flowers axillary 

 along the stem. 



In crevices of shaded rocks, rarely in calcareous habitats ; 

 Europe, Asia, and, in North America, from Greenland to Brit- 

 ish Columbia south to northern United States and to Cali- 

 fornia. Rare in our region. 



Huntingdon : Porter. (Porter's Catalogue). 



2. Amphidium mougeotii (Bryologia Europaa) Schimper. 



(Zygodon mougeotii Bryologia Europsea ; Anocctangitim mou- 

 geotii Lindberg) . 



Densely cespitose, in large tufts, yellowish-green above, 

 rusty to blackish below : stems usuall}^ 2-6 cm. high, dichoto- 

 mously branching ; leaves spreading or erect-spreading, crisped 

 when dry, elongate lance-linear, acuminate, carinate, margin 

 narrowly revolute below, slightly irregular above ; costa strong, 

 vanishing at apex ; basal leaf-cells narrowly rectangular, rather 

 thick-walled, above shorter, sub-quadrate to rounded, incras- 

 sate, hardly papillose, pellucid ; perichsetial leaves sheathing 

 only the base of seta : seta about 2-3 mm. long ; capsule short- 

 ly exserted, narrowly oval with a distinct neck, when dry 

 uiceolate, contracted below mouth, 8-striate : peristome none; 

 lid low, obliquely rostrate, the length of the beak more than 



