OF WESTERN' PENNSYLVANIA 115 



Key to the Species. 



a. Autoicoit:.: leaf-margins plane: seta 1.5 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. vioiigcotii. 



1. Amphidium lapponicum (Hedwig) Schimper. 

 (Anictangium lapponicum Hedwig; Zygodou lapponicus Bryolo- 

 gia Europcea). 



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

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

 fiexuous-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; perichretial 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 stride, 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, brow'nish ; 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. 



Huntindon ; Porter. (Porter's Cataloue). 



2. Amphidium mougeotii ( Hryologia Europcea) Schimper. 



(Zygodon inoitgcotii Bryologia Europ?ea ; Anoectangium uion- 

 gcotii Lindberg). 



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

 rusty to blackish below ; stems usually 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 

 urceolate. contracted below mouth. 8-striate ; peristome none; 

 lid low, oblic'iielv rostrate, the lensfth of the beak more than 



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