Jennings: Manual of Mosses — II. Andreaeales 43 



This peculiar order is represented by but one family, the Andreaeaceae, 

 which consists of only one genus, Andreaea [Ehrhart] Hedwig. There are 

 about 125 species, alpine and sub-alpine and widely distributed; 19 species 

 occur in North America, only 3 of which, however, are to be expected in our 

 general range. 



I. Andreaea [Ehrhart] Hedwig 



A. Leaves ecostate 1. A. rupestris 



A. Leaves costate B 



B. Leaf elongate acuminate from an oval base; costa filling about the middle two- 

 thirds of the leaf-apex, not excurrent 2. A. Rothti 



B. Costa practically filling the whole apex of the leaf and excurrent 



{A. Rothti var. crassinervia (Bruch) Moenkemeyer) 



1. Andreaea rupestris Hedwig 



(A. petTOphila Ehrhart) 



Densely cespitose, dark brown to blackish: stems slender, about 1.5-2.5 cm 

 high, usually branching, more or less erect; leaves when dry very brittle, 

 crowded, small, ovate to lance-ovate, imbricated, often falcate-secund from an 

 erect base, usually c^tuse, entire, margin incurved; no costa; (the leaves are 

 so dense that they usually require bleaching in a solution of caustic potash 

 before the leaf -cells can be made out under the microscope); basal leaf -cells 

 narrow-rectangular, very incrassate, sinuose, above becoming shorter, the median 

 and upper cells rounded and angular-oblong, longitudinally seriate, dorsally 

 strongly papillose: fruit similar to that of Sphagtnim in being enclosed in the 

 perichaetium until mature, when it is quickly exserted on an outgrowth from 

 the tip of the leafy shoot similar in appearance to a short seta and termed 

 the pseudopodium; calyptra very thin and irregularly torn at base; capsule oval, 

 opening usually by four perpendicular slits along the sides but remaining 

 united at apex and base; columella persistent; spores smoothish, mature in late 

 spring. 



In mountainous or hilly regions on non-calcareous rocks. In North Amer- 

 ica from the Arctic regions south to northern United States and south to 

 Georgia, Colorado, and California. Occurs in northeastern Pennsylvania and 

 in northern West Virginia. 



2. Andreaea Rothii Weber and Mohr 



(Andreaea rupestris Roth) 

 Plate LX 



Small, blackish; stems 1-2 cm. long, branching to form tufts; leaves spread- 

 ing to falcate-secund, up to 1-1.5 mm long, suddenly elongate acuminate from 

 an oblong or ovate base, entire to faintly crenulate; costa strong, yellowish, 

 more or less plainly percurrent; alar cells rounded-quadrate, the median basal 

 ones variously either rounded or linear-oblong with irregular lumen, the upper 

 rounded, small, all densely incrassate; perichaetial leaves sheathing, suddenly 

 contracted into a short acuminate or linear point; capsule oblong-ovate, dark, 

 about .75 mm long, exserted on a twisted seta, splitting into four valves which 



