CHILEAN SPECIES OF METZGERIA. 303 



cells average about 33 X 21 ^t but are not always as small as this, 

 averaging in one area as much as 41 X 33 (jl. Since the absence of 

 cilia is the only important feature distinguishing M. nuda from M. 

 dccipiens, and since this feature has been proved inconstant, the two 

 species are clearly synonymous. 



8. Metzgeria epiphylla, sp. nov. 



Yellowish or whitish green, not becoming bluish after drying, scat- 

 tered or in thin depressed mats, loosely adherent to the substratum: 

 thallus prostrate, repeatedly dichotomous but also with ventral vege- 

 tative branches, flat or slightly convex, well-developed thalli mostly 

 0.6-0.8 mm. wide and rarely as much as 1 mm., the forks mostly 

 0.6-2.4 mm. apart; costa bounded both dorsally and ventrally by two 

 rows of cortical cells; wings mostly eight to thirteen cells broad, the 

 cells mostly 37 X 30 n, the walls thin or slightly and uniformly thick- 

 ened, sometimes with indistinct trigones; hairs varying in abundance; 

 marginal hairs usually occurring singly but not infrequently in pairs, 

 sometimes branched at the apex and acting as rhizoids, mostly 0.1- 

 0.15 mm. long and 8-10 fx wide; ventral hairs sometimes lacking, 

 sometimes sparingly developed on the costa and still more sparingly 

 on the wings, similar to the marginal hairs: inflorescence dioicous: 

 cf branches subspherical, smooth, 0.3-0.4 mm. long and 0.25-0.35 

 mm. wide: 9 branch broadly obovate, 0.3-0.35 mm. long and wide, 

 hairs abundant on the margin and usually on the ventral surface; 

 calyptra about 1 mm. long and 0.45 mm. wide, the hairs abundant 

 above the middle, few and scattered below: capsule brown, oval, 

 mostly 0.5-0.6 mm. long and 0.35-0.4 mm. wide, the valves (when 

 spread out) 0.6-0.75 X 0.2-0.25 mm. ; spores pale brownish yellow 

 and very minutely punctulate, 16-18 /x in diameter; elaters 0.3-0.4 

 mm. long, 6 /z wide in the middle and with a single broad spiral band 

 running the entire length: gemmae sometimes abundant, arising on 

 more or less narrowed and specialized branches with limited growth, 

 marginal or submarginal and dorsal in position, orbicular to oval, 

 plane or slightly convex and bearing a few short marginal hairs 

 slightly displaced to the concave surface. 



Specimens examined: Corral, 1896, Dusen 82, 191 (U., as M. 

 australis, and listed under this name by Stephani, 20, p. 19) ; same 

 locality, 1905-06, Thaxter 10a, 108, llfl (H., Y.). No. 10a, collected 

 by Professor Roland Thaxter, may be designated the type. 



In its vegetative features M. epiphylla resembles M. dccipiens so 



