OF WESTERN PENNSYLVANIA 217 



1. Forsstroemia trichomitria (Hedwig) Lindberg. 

 (Fterigynandnmi trichomitrium Hedwig; Leptodon trichomitriits 

 Mohr). 



(Plate XXXII) 



Broadly cespitose, rather rigid, yellowish-green; primary 

 stems creeping, filiform, the secondary stems numerous and 

 abundantly branched; leaves close, loosely erect-spreading, 

 lance-ovate, shortly acuminate to acute, entire, when dry some- 

 what plicate, about 1.5-2 mm. long, the extreme apex rather 

 blunt, the base concave, the margins reflexed; perichsetial 

 leaves loose in texture, the inner sheathing, reaching to the 

 base of the capsule or a little higher : seta short, slightly longer 

 than the capsule; capsule ovate-cylindric, thin-walled, rather 

 gradually narrowed below, about 3-4:1, about 1.5 mm. long; 

 exothecial cells rather incrassate, irregularly polygonal to 

 rectangular-oblong, several rows at the narrowed mouth 

 smalier, rounded-quadrate - and dark-castaneous ; peristome- 

 teeth whitish, lance-linear, rather remotely articulate, some- 

 times perforate along the divisural, the inner peristome entire 

 to more or less torn, adhering to the ventral surface of the 

 teeth ; lid short-rostrate ; spores mature in winter, orange-in- 

 crassate, almost smooth, about .023-.025 mm. 



In woods on trees, rarely on rocks ; Asia, and from New 

 England to Ontario and the Gulf States. Common in Eastern 

 Pennsylvania but rare in our region. 



McKean : Near Latshaw, N. Y., north of Bradford, 



August 25, 1895. D. A. B. (Figured). 



Family XXVII. NECKERACEAE. 



Dioicous, rarely autoicous or synoicous ; sexual clusters only 

 on secondary shoots and their branches, with filiform, often 

 yellowish paraphyses : slender to robust, mostly stiff, laxly cespi- 

 tose : stem somewhat dorsiventrally flattened, with or without 

 a rudimentary central strand ; primary stem more or less 

 creeping, mostly filiform, mostly sparsely fasciculately radicu- 

 lose; secondary stems more or less elongate and ascending or 

 much elongated and pendent, mostly distantly or symmetrical- 

 ly pinnate, thickly-leaved, julaceous or flattened; leaves nearly 

 always pluri-seriate, uni-stratose, of various forms ; costa most- 

 ly delicate, homogenous, simple or double or none ; median 

 cells mostly prosenchymatous, the apical sometimes parenchym- 

 atous, the basal often colored, the alar sometimes differ- 

 entiated : capsule mostly erect and symmetric, peristome most- 

 ly double, teeth yellowish to brownish, lance-linear, dorsally 

 sometimes abnormally thickened, ventrally trabeculate ; the 

 inner peristome with mostly low carinate basal membrane, 

 raiely rudimentary or none, segments linear to filiform, often 



