64 



being about 7-10 jjl. These cells are very strongly papillose on 

 both surfaces, a single large central projection being long-pointed 

 or more commonly irregularly shaped or slightly pronged ter- 

 minally. This arrangement of papillae leaves the cell-walls very 

 clearly defined. A border region is considerably differentiated 

 beginning at or near the apex and running downward with a 

 width of about 2 cells until it finally widens to join the differen- 

 tiated basal cells. The cells of this border lack the papillae and 

 are about twice as long as wide. This border differentiation is 

 very striking both in leaf-section and surface-view. The in- 

 florescence is autoicous, the antheridia on an inconspicuous lateral 

 branch. The capsule is small and well included in the leaves, 

 nearly spherical (.4 mm. in diameter) with an inconspicuous 

 apiculus, without operculum; its color is a shining yellowish 

 brown, it is connected by a very short seta (.08 mm.) to the 

 vaginule, which is cylindrical or elongated barrel-shaped (.23 

 mm. high and half as thick) without swollen base. The epidermis 

 of the capsule constitutes a thin brittle plate, striking in a palisade- 

 like arrangement of the exothecial cells except at base and apex. 

 These are very elongate vertically with the two long sides parallel, 

 the ends angular or straight, making the cells elongated rectan- 

 gular to hexagonal (up to 15X50 ^u). The thin lines of cell- 

 division are the natural lines of fracture and the capsule seems 

 very brittle along them so that the spores are quickly lost. The 

 latter are light yellow in color, very slightly roughened and about 

 15-20 jLt in diameter. 



In the European species, several specimens of which I owe to 

 the kindness of Mrs. Britton and Dr. Roth, the plant does not 

 appear so raised from the substratum, lacks the conspicuous 

 superficial protonema* and averages in fact rather shorter, with 

 shorter leaves, and capsule much larger in proportion and more 

 conspicuously exposed. f The color of the capsule is a more 

 reddish brown, its apiculus is still less pronounced, its outer 

 membrane not so brittle, nor its exothecial cells quite so long 



*Limpricht says (Rabenhorst, Kryptogamen Flora, IV, i, 195. 1886) that 

 the protonema of A. carniolicum is subterranean. 



t Fleischer (Malpighia, VII, 317. 1893) gives maximum dimensions of the 

 plant and leaves of A. carniolicum equalling or excelling those of A. kansanum. 



