284 A MANUAL OF MOSSES 



7. CALL1ERGON (Sullivant) Kindberg. 



Mostly dioicoits : more or less robust, stiffly and loosely 

 cespitose, greenish to brownish or yellowish, rather lustrous; 

 stem long, in water and in deep swamps not bearing rhizoids 

 but assuming a more or less erect habit, in dry places procum- 

 bent and bearing rhizoids, irregularly to regularly pinnately 

 branched ; stem-leaves large, erect-spreading to imbricate, con- 

 cave, rarely somewhat plicate, ovate to oblong or almost cir- 

 cular, the apex broadly rounded to cucullate, the margin plane 

 and entire or rarely somewhat revolute below ; costa mostly 

 strong and almost complete, sometimes indistinctly forked at 

 the end ; leaf-cells elongate, linear-hexagonal, shorter below, 

 the alar forming a distinct group of large, quadrate, rectangu- 

 lar, and polygonal cells, at first thin and hyaline but later 

 colored and incrassate, the alar portion of the leaf excavate ; 

 branch-leaves smaller, narrower, the apex often canaliculate; 

 the inner perichsetial leaves erect, more or less long-acuminate, 

 mostly non-plicate, with a simple costa : seta mostly very long, 

 drying flat, red to castaneous ; capsule inclined to horizontal, 

 thickly oblong to oblong-cylindric, more or less dorsally gib- 

 bous, drying arcuate, smooth ; annulus none to broad ; peris- 

 tome normally hypnoid ; lid convex, acute to obtuse-conic. 



A genus of about 10 species of aquatic, largely swamp- 

 inhabiting mosses, confined to temperate and cold regions: 8 

 species occurring in North America ; 1 species within our range 

 and 2 others to be expected. 



Key to the Species. 



a. Costa extending to the middle or a little above. 



(C. stramineum (Dick- 

 son) Kindberg). 

 a. Costa sub-percurrent. b. 



b. Slender, simple or sparingly branched; alar cells gradually en- 

 larged. 1. C. cordifolium. 

 b. Robust, profusely branched: alar cells abruptly enlarged. 



(C. giganteum (Schini- 

 per) Kindberg). 



1. Calliergon cordifolium [Hedwig] Kindberg. 



(Hypnum cordifolium Hedwig: Amblystegium cordifolium De- 

 Xotaris ). 



(Plate XL) 



Slender, tall, loosely and softly cespitose, green : stems 

 brownish, 10-20 cm. in length ; when growing in swamps, 

 more or less erect; when in dryer situations, more procumbent, 

 and furnished with rhizoids ; sparsely branched, the branches 

 more or less pinnately branched or simple, cuspidate at the 

 tips ; leaves distant, erect-spreading to spreading, thin, shrink- 

 ing when dry, large, 2-5 mm. long, concave, cordate- to oblong- 



