THE THALLOSE HEPATICAE OE THE JUAN FERNANDEZ ISLANDS 569 



The inflorescence of R. variabilis seems to be definitely dioicous. The 

 male branches (Fig. 3, B) are sparingly produced and arise singly from the axis 

 or a primary branch, rarely from a secondary branch. 1 he inflorescence (Fig. 

 3, H), which is usually without a stalk, is mostly 0.3—0.45 mm. in length and 

 about 0.3 mm. wide. The anthcridia in most cases number from six to ten and 

 the openings into the antheridial chambers are separated by one or two rows 

 of cells. The wing is crenulate, spreading to suberect, and onl\- one cell wide. 

 The female branch figured is the only one demonstrated. It is very short and 

 shows a narrow and irregularly crenulate wing. The calyptra is 1.8 mm. in 

 length by 0.45 mm. in width and is so old and battered that the corona is no 

 longer distinguishable. The surface, however, still bears vestiges of small pro- 

 jecting clusters of rounded cells. 



Among the species of Riccardia previously reported from Chile., the closest 

 ally of R. variabilis is evidently R. coniniitra (Steph.) F^vans, known from three 

 stations along the western coast.' In this species the thallus is about as large 

 as that of R. variabilis and is almost as irregular in its branching. The branches 

 show, moreover, a similar vague differentiation into photosynthetic branches and 

 stolons, and the axes of various ranks are only four to six cells thick in the 

 middle. Even the male inflorescences are much alike in the two species, except 

 that in R. coniuiitra the upper surface is often roughened by bulging cells. 

 There are, however, several important distinctions to be noted. In R. variabilis, 

 for instance, a typical photosynthetic branch broadens out conspicuously toward 

 the apex; there is little or no tendency for the branches to become attenuate, 

 except perhaps in the case of the stolons; and the external cells of the thallus 

 are distinct!}- smaller than the interior cells, except again in the case of the 

 stolons. In R. conimitra, on the other hand, the photosynthetic branches do 

 not broaden out to any extent; there is a strong tendency for the branches and 

 even for the main axes to grow out into slender attenuate extensions; and the 

 external cells of the upper surface are usualh- distinctly larger than the interior 

 cells, the contrast being especially marked on the narrow branches. 



Another species of the Southern Hemisphere with which R. variabilis 

 should be compared is Anenra subaiitarctica Kaalaas of the Crozet Islands,^ 

 known to the writer from description only. This species agrees with R. varia- 

 bilis in general habit, the primary axis is described as five cells thick, and a 

 marked contrast in size is indicated between the external and internal cells. 

 The inflorescence in A. subaiitarctica, however, is autoicous; the branches are 

 described as attenuate, although the axis is said to be dilated as a rule at the 

 apex; and the marginal wing, even when present, is said to be only one cell 

 wide. The Crozet Island species is furthermore somewhat larger than R. varia- 

 bilis, the length being given as 1.5 — 2 cm. and the width as 0.5 — 0.6 mm. 

 Kaalaas suspected that the specimens from Kerguelen Island, which MlTTEN 

 had reported under the name A. niultifida, might possibly be the same as his 

 new species, but he left the matter in uncertainty. 



Area of distribution: Chile (Concepcion); Masatierra. 



' Trans. Connecticut Acad. 25: 156 f. 6 (1921). 

 - Xvt Mag. Naturv. 49: 87 f. i (191 1). 



