-66 ALEXANDER \V. EVANS 



by a unistratose wing one to three cells wide. The cells of the superficial layer 

 average about 60 X 42 [i, becoming shorter toward the edges, the marginal cells 

 being almost isodiametric. Some of these marginal cells project slightly, forming 

 irregular and often scattered crenulations, but the wings are sometimes nearly 

 or quite entire. The interior cells are mostly 160 — 200 [i in length and 80 (j- 

 in width, so that the contrast in size between the exterior and interior cells is 

 pronounced in cross section. The walls are thin and delicate throughout. 



On the whole the branching is less regular than SCHIFFNER implies in 

 his description of R. insularis, and it is sometimes difficult to draw a sharp 

 line between the main axis and the primary branches. Uusually, however, the 

 latter are only 0.5 -- 1 cm. long, i — 1.5 mm. wide and three or four cells thick 

 in the middle. Their structure is essentially the same as that of the axis. In 

 most cases the primary branches are simple, but sometimes short tertiary 

 branches or their rudiments can be demonstrated. An occasional branch is 

 modified into a stolon-like structure or becomes stolon like in the outer part. 

 Such a branch is only 0.2-0.3 mm. wide and is subterete and wingless. The 

 median portion is usually five to seven cells thick, and the interior cells are only 

 slightly larger than the surface-cells. 



In the Masatierra specimens the inflorescence seems to be constantly 

 autoicous (Fig. 2, D, E), although male and female branches sometimes arise 

 in close proximity. The male branches are numerous and are borne, singly 

 or in groups of two or three, either on the main axis or on a primary branch. 

 The inflorescence occupies the greater part of the branch (Fig. 2, H) and 

 measures 0.6—1 mm. in length by 0.3—0.4 mm. in width. It is bordered by 

 a spreading crenulate wing, one cell wide, and usually develops from eight to 

 sixteen antheridia, even more being present in some cases. The openings into 

 the antheridial chambers are separated by two rows of cells, although three 

 rows are sometimes present between the two longitudinal rows of antheridia. 



The female branches (Fig. 2, D — F) are similar in size and position to 

 the male branches. The archegonia are usually numerous, from twelve to 

 twenty-four being often present, and the involucre consists of a ciliolate wing, 

 with cilia two or three cells long, supplemented by a few similar cilia among 

 the archegonia. The »calyptra» may attain a length of 4 mm. and a diameter 

 of 0.8 mm. at maturity but is often smaller, SCHIFFNER giving the length as 

 2 mm. and the diameter as 0.5 mm. The surface sometimes bears a few un- 

 fertilized archegonia in the lower part and, in addition, scattered outgrowths, 

 some of which resemble the involucral cilia. Otherwise the surface is smooth 

 or nearly so and the apical corona is inconspicuous. 



The capsule is essentially like that of R. adglntinata, in so far as the 

 local thickenings in the cells of the wall are concerned. It agrees also in all 

 respects with Schiffner's description, even to the absence of half-annular 

 thickenings in the marginal rows of the valve cells. At maturity it measures 

 I — 1.2 mm. in length by 0.35 - 0.5 mm. in width. The yellowish spores are 

 mostly 14—16 [X in diameter with slightly thickened minutely dotted walls; and 

 the elaters, each with a loosely wound broad spiral, measure 0.3- 0.45 mm. by 

 12 — I4tj.. 



