214 A MANUAL OF MOSSES 



On rocks and trees, mainly confined to temperate regions : 

 11 genera; only 2 genera in our region. 



Key to the Genera. 



a, Costa double or more. 1. Leucodon. 



a. Costa single. 2. Forsstroemia. 



1. LEUCODON Schwaegrichen. 



Dioicous : blackish to yellowish or brownish-green, dull 

 or lustrous : primai-y stems very long and branched ; secondary 

 stems usually simple, equally high, sometimes more or less 

 pinnate, thickly leafy; leaves drying appressed, straight or 

 secund, mostly pluri-plicate, when moist spreading, ovate- 

 acuminate to short-acute, entire or apically serrate, ecostate; 

 median leaf-cells smooth, oblong-rhombic, the basal reddish- 

 yellow; inner perichsetial leaves high-sheathing, long-acumi- 

 nate : seta mostly more or less elongate, reddish ; capsule most- 

 ly exserted, oblong to oval (or globose), reddish brown to 

 blackish, with a small mouth and short collum, stomata none ; 

 annulus present; peristome double with the inner peristome 

 rudimentar)^ or apparently lacking; teeth whitish to yellow- 

 ish, mostly gaping in the middle or divaricately cleft ; lid conic, 

 constricted at the base, sometimes obliquely rostrate; calyptra 

 smooth, cucullate, enveloping the capsule and upper end of 

 seta ; spores .025-.035 mm., yellowish-green, finely warty. 



A widely distributed genus of 36 species, occurring on 

 trees and rocks ; 8 species in North America ; 3 species, prob- 

 ably, in our region. 



Key to the Species. 



a. Leaves plicate; secondary stems well developed: seta about 2-3.S 

 mm. long, with capsule emergent but shorter than the perichsetial 

 leaves. 1. L. brachypus. 



a. Secondary stems less developed: capsule long-exserted. 



b. 

 b. Leaves ovate-elliptic, rather abruptly and shortly acuminate, 



scarcely plicate. 2. L. julaceus. 



b. Leaves lance-ovate, long and slenderly acuminate, much plicate. 



3. L. schiroides. 



1. Leucodon brachypus Bridel. 

 (Plate XXXI) 

 Moderately robust, brownish to light green, loosely tufted : 

 stems usually at least 5-6 cm. long, with rather numerous 

 secondary simple or branched divisions ; leaves about 2 mm. 

 long, ovate, bluntly acute to short-acuminate, obscurely more 

 or less secund, usually plicate with two folds, entire to ser- 

 rulate above ; costa none ; median leaf-cells linear-fusiform 

 and castaneous pellucid at base, the interior median rhombic, 

 about 5-8:1, grading to oval at the apex, the marginal basal 

 rounded-quadrate to transversely oblong, all cells incrassate; 



