1 8 POLYTRICHACEAE 



the greater part of the width of the leaf above the base; upper 

 cell of the lamellae differentiated.* 



Capsules prismatic, four-to six-angled, often nearly cubical. 

 Peristome teeth generally sixty-four. Calyptra densely hairy. 



Key 



i- — Leaf margins serrate, not infolded 2 



Leaf margins entire, thin and infolded 3 



2 — Capsules cubical, beak short commune 



Capsules much longer than broad, beak long, neck tapering .. Ohioense 

 3 — Plants of dry situations, small (1 cm. to 2 cm.), leaves with long 



white awns piliferum 



Plants larger, leaves without white awns ! 4 



4 — Plants of lowlands without felted radicles; capsules 3 mm. to 5 mm. 



long juniperinum 



Plants of pine barrens or subalpine regions; stems covered with a 

 dense felt of radicles, capsules 2 mm. to 3 mm. long striatum 



Our species are readily divided into two groups, as shown in 

 the key. One with serrate plane margins and the other with 

 margins thin and infolded, not serrate except at the extreme 

 apex. These species are all earth-growing. 



P. commune L. Very common. A nuisance in old fields 

 where it often crowds out the grass. According to Prof. J. F. 

 Collins most of our material from Long Island and probably 

 elsewhere is var. perigonale (Mx.) B. & S. June-July. 



P. Ohioense R. & C. Common, more frequent in wooded 

 places. June. 



P. juniperinum Willd. Orient, Latham; Hempstead, Hulst 

 (25288)!; High Bridge, Denslow; Huntington, L. Id., J. E. 

 Rogers; Garretstons, S. Id., E. G. B.; Forked River, N. J., 

 Lighthipe; Closter, N. J., Austin. All but the first two local- 

 ities are represented at the Bronx. 



P. piliferum Screb. Dry barren soil, frequent. June-July. 



P. strictum Banks. "Pine barrens, common," Flora N. J.; 

 Lakehurst, N. J., in and around bog!!; New Haven, Bry. Ct. 



* In making cross-sections of the leaves to determine the nature of the 

 terminal cells of the lamellae, the upper portion of the leaf should be used, 

 as these cells are not characteristic near the base. 



