304 Alexander W. Evans, 



on account of the dilated basal portion. It measures about 1 X 0.9 

 mm., and the three to five blunt teeth are restricted to the apical 

 region. Two or three antheridia are found in the axil of each bract. 

 Closely related to P. andicola, as Gottsche notes, is the Mexican 

 P. truncata Gottsche/ originally described from specimens collec- 

 ted by Liebmann in the Sempoaltepec region and afterwards found 

 by other collectors. In this species the apices of the leaves tend 

 to be truncate, although in some of Gottsche's figures this condition 

 is not pronounced, and the teeth are longer and sharper than in 

 P. andicola. In P. subconvoluta Gottsche 2, another Mexican spe- 

 cies known only from a single specimen found by an unknown collec- 

 tor, the leaves are much like those in P. andicola and P. truncata, 

 but the postical bases are not dilated in such a way that they 

 forms crests. 



6. Plagiochila Binghamiae sp. nov. 



On rocks, Huadquiila, 5,000 feet, July 30, 1911. Named in honor 

 of Mrs. Alfreda Mitchell Bingham, a patroness of the Expedition. 



Yellowish or brownish green, not glossy, groAving in loose mats : stems 

 mostly 2 — 3 cm. long and 0.3 mm. in diameter, more or less rigid, ascending, 

 simple or with an occasional branch, the branches obliquely spreading, almost 

 invariably intercalary, similar to the stem but often with somewhat smaller 

 leaves : leaves alternate, contiguous or loosely imbricated, widely spreading 

 (at an angle of about 75 degrees), somewhat convex, ovate, 1.5—2.4 mm. 

 long, o.g — 1.2 mm. wide, narrowly decurrent both antically and postically, 

 antical margin somewhat revolute toward the base, sUghtly incurved to 

 slightly outcurved, entire, postical margin more or less involute in decurrent 

 portion and for a variable distance beyond, sometimes as far as the middle, 

 outwardly curved but not dilated at the base, entire or with a single tooth 

 in the outer part, apex broad and rounded with three or four scattered teeth, 

 the latter irregular, mostly four or five in all, usually three or four cells long 

 and three or four cells wide at the base, abruptly pointed ; leaf-cells averag- 

 ing ijfx in the apical region, 28 X 19 A* in the middle, and 32 X 23, u at the 

 base, walls thin but with distinct triangular trigones, one or two of the sides 

 usually bulging, intermediate thickenings few, oval, thickenings often con- 

 fluent, especially toward the base and along the margin ; cuticle smooth : 

 underleaves minute, about o.i X 0.07 mm., deeply cleft almost to the base 

 into two to four ciha : propagula numerous, with small leaves : remaining 

 parts not seen. Fig. 2. 



Although most of the branches in this species are intercalary 

 a terminal branch is occasionally produced and is of considerable 



1 Mcx. Leverm. 127. pi. 10. f. 1—4. 1863. 



2 Mex. Leverm. 120. pi. 3, f. 1—10. 1863. 



