148 Alexander W. Evans, 



II. RiccARDiA ALCicoRNis (Hook. f. & Tayl.) Trevis. 



Jungennannia (Aneura) alcicornis Hook. f. & Tayl. Jour. Bot. 



3: 479. 1844. 

 Aneura alcicornis Tayl. & Hook. f. in G. L. & N. Syn. Hep. 499. 



1846. 

 Riccardia alcicornis Trevis. Mem. 1st. Lombardo HI. 4: 431. 



1877. 

 Aneura subnigra Steph. Kimgl. Svenska Vet.-Akad. Handl. 46°: 



9. /. I, h. 1911. 



Specimens examined: Hermite Island, Hooker (M., type of 

 Jungermannia alcicornis) ; Puerto Angosto, Desolation Island, 

 1896, Dusen 16 j (N. Y., as Aneura tenax, and apparently listed 

 under this name by Stephani, 29, p. 9) ; Peel Inlet, 1908, 

 Skottsberg 8^ (U., the first specimen cited by Stephani under 

 A. subnigra). 



The following additional localities from the literature may be 

 cited; Port Famine, Straits of Magellan, Andersson (i, p. 13, as 

 Jungermannia alcicornis) ; Sky ring, Skottsberg (32, pp. 5 and 9, 

 as A. alcicornis and A. subnigra). 



There is little to connect R. alcicornis with any of the preceding 

 species. In some respects it shows an approach to R. corralensis, 

 but there are striking differences in histological detail as the fol- 

 lowing description will demonstrate. The plants studied grew in 

 loose tufts in admixture with other bryophytes. They vary in color 

 from pale to dark green and sometimes exhibit a purplish black 

 hue even while still young. So far as dried material indicates, the 

 plants were prostrate or perhaps ascending at the tips and produced 

 rhizoids abundantly wherever they came in contact with the sub- 

 stratum. The amount of differentiation shown is less than in most 

 antarctic species of the genus. 



The main axis with its long-continued growth (Fig. 5, A-C) 

 reaches a length of 0.5-1 cm. (or even 2 cm. according to 

 Stephani) ; its width is mostly 0.4-0.6 mm., and its thickness about 

 0.2 mm. In cross section (Fig. 5, D) it shows a biconvex outline 

 with rounded ends, the ventral surface being more bulging than the 

 dorsal. No indication of a marginal wing is present. The cells 

 are unusually narrow and the contrast in width between the super- 

 ficial cells and the interior cells is very slight. This is well brought 



