NorRTH AMERICAN SPECIES OF LESKEA Tt 
or less open, shorter than the teeth ; annulus of two rows of cells; 
’ 
operculum short-conic, obtuse or apiculate; spores smooth, 
II~14 #4, mature in early summer. On the base of trees or rot- 
ten wood; more rarely on stones or the ground in wet places, 
(PLATE 15, FIGS. 14-27.) 
Type Locatity: Pennsylvania ; type in Herb, Boissier. 
ExsiccaTAE: Drumm. Musc. Amer. so5,; Austin, Musc. 
Appalach. 270 ; Ren. & Card. Musc. Am. Sept. 793. 
It_usrrations: Cardot, Bull. Herb. Boissier, '7: p/. 9. f. 4. 
Sulliv. Icon. Musc. f/. 77 is probably a form of ZL. gracilescens, 
as the margins of the stem-leaves are recurved. Dr. Robinson is 
unable to find the specimen in the Sullivant collection from which 
these drawings were made. 
L. obscura has about the same range as the preceding, except 
that it is more frequent southward. Not rarely it grows mixed 
with Axomodon attenuatus and A. obtusifolius, to both of which it 
bears a superficial resemblance. In drying the leaves commonly 
take on an ashen or plumbeous tint and the lower surface a finely 
granular appearance. In its typical form ZL. obscura differs from L. 
polycarpa and L. gracilescens by its thicker, asymmetric, rounded- 
obtuse leaves, not plicate and with plane margins ; the segments 
moreover are stouter, more densely papillose and usually more 
open. Some difficulty may be experienced in discriminating be- 
tween this species and certain forms of L. polycarpa paludosa. The 
leaves, however, of the latter are usually longer, more or less 
secund and acuminate, obliquely and sometimes obtusely pointed, 
the leaf-cells unipapillate and the reddish-brown capsule longer, 
as also the segments. The most valuable character in differentiat- 
ing ZL. obscura from the preceding species is the thicker texture of 
the leaves, the cells of which are covered with minute papillae, 
resembling those of Anxomodon attenuatus, but not so mary nor so 
distinct.* 
* We are indebted to M. Cardot for having first called our attention to the distin- 
guishing characters, at least in part, of Z. obscura. In his valuable ‘* Revision des 
types d’ Hedwig et de Schwaegrichen ’’?(Bull. Herb. Boissier, 7 : 348) we are told 
that there are two series of specimens on the sheet of the type of this species, named 
respectively ‘‘ a. arborea’’ and ‘‘ 4, terrestris’’; that the latter is the one to which 
Hedwig’s description applies and that the former is Z. polycarpa. On fi. 9 f. 4 of this 
** Revision ’’ (1. c.) are drawings of two leaves taken from the ‘‘ arborea’? series. As 
far as it is possible to determine, these are identical with the leaves of Z. gracilescens 
