154 EVANS 



D. tenuis is a somewhat aberrant member of the genus. In 

 the majority of the species which have been described the keels 

 of the perianth are spinose, ciliate or distinctly toothed, some- 

 times being prolonged as horns. In D. temcis the keels are 

 rounded in the upper part and are practically smooth (PL VII, 

 fig. 10). It is not, however, unique in this respect, but agrees 

 with 2 American species, D. sitbulata Steph. and Lejeuvea 

 (Drefianolejamea) anoplantka Spruce. This peculiarity, al- 

 though important, is hardly sufficient to exclude these species 

 from Di'ejianolejeunea, as it is unsupported by differences in 

 vegetative structure. 



The differential characters which separate D. tc7iuis from the 

 2 American allies just mentioned have already been noted by 

 the writer in another connection. 1 The marginal teeth which 

 are there alluded to are exceedingly variable and on many 

 leaves are absent altogether (PI. VII, fig. 12). On other 

 leaves they are very pronounced (PI. VII, fig. 11), and there 

 are all gradations between these 2 extreme conditions. There 

 is apparently no definite correlation between the size of the leaves 

 and the length of these marginal teeth. Another variable char- 

 acter is found in the leaf-cells. These are sometimes plane and 

 sometimes markedly convex or even papillate. 



10. HARPALEJEUNEA INTERMEDIA Evans, new 



species. 



(PI. VIII, figs, i-ii.) 



Pale green, more or less tinged with yellow or brown, grow- 

 ing in depressed mats ; stems prostrate, 0.045 mm. in diameter, 

 loosely adherent to the substratum, sparingly and irregularly 

 branched, the branches widely spreading, similar to the stem ; 

 leaves contiguous to imbricated, the lobe obliquely spreading to 

 suberect (widely spreading when flattened out), convex and re- 

 flexed at the apex, falcate-ovate, 0.28 mm. long, 0.17 mm. 

 wide, abruptly dilated from a narrow basal region and attached 

 by a short and almost longitudinal line, antical margin slightly 

 incurved near base, then strongly outwardly curved to the apex, 



■Bull. Torrev Club 30: 25. 1903. 



