1036 SUMMARY OF CURRENT RESEARCHES RELATING TO 



pendulum, belonging to the section Cladodimn, and its allies = The 

 peristome here is of a very beautiful appearance and structure. We 

 find a multiplication of cells in the layer which separates the two 

 peristomes, explained, no doubt, by the influence of the internal 

 peristome, the network of which is always more complicated, while 

 the external peristome exhibits a tendency to be reduced, on its 

 ventral side, to five rows of simple plates. 



The structure of the peristome is described in detail in several 

 other species of Br yum. 



Spores of Pottia.* —Dr. G. Venturi insists on the importance of the 

 characters of the spores, hitherto too much neglected, in determining 

 the species and genera of Musci and Hepaticae ; the important cha- 

 racters relating chiefly to the form of the spores, and to the nature of 

 their outer coat. 



By using these characters, the moss hitherto described as Pottia 

 minutula var. conica is clearly seen to be a totally, distinct species ; 

 the spores being strongly tuberculated, instead of covered with minute 

 hairs or spines, as in P. minutula, in addition to other differences in 

 the capsule. The spores of P. minutula var. conica are those of P. 

 Starhei, a species distinguished by the peculiarity that it presents every 

 possible gradation between a perfect peristome and the complete 

 absence ot a peristome. Using the same test, P. mmutula var. ohlonga 

 remains as a variety of the typical species ; while P. minutula var. 

 wutica and P. lanceolata var. leucodonta display an unquestionable 

 affinity with P. Starhei. 



Stomata of Marchantia.f — Prof. C. E. Barnes calls attention to 

 the erroneous figures of the stomata of Marchantia in all English 

 works on botany. They are shown with six cells in circumference, 

 whereas they have only four. The shapes of the innermost cells, 

 the true guard-cells, and of the outermost cells of the chimney-like 

 stoma, are not correctly drawn. 



Pleuroweisia, a new genus of Mosses. J — Herr K. Schliephacke 

 describes under this name a new genus of Musci from Switzerland 

 with the following characters : — Perennial slender rooting densely 

 casspitose mosses. Stem erect, slender, usually dichotomous above, 

 uniformly leafy. Network of the leaves oblong-rectangular below 

 pellucid, minutely quadrate above, very minutely papillose. Inflor- 

 escence dicecious ; reproductive organs of both kinds lateral. Capsule 

 gymnostomous, seated on a slender seta, exannulate ; operculum with 

 an oblique and very long beak. Calyptra cylindrical, slit on the side, 

 covering the operculum, often falling off along with it. The type- 

 species P. SchliepJiacJcei was found in a glacier-stream near Pontresina. 



Mosses of Terra-del-Fuego.§ — Herr C. Miiller has examined a 

 large collection of mosses from this district, including a considerable 

 number of new species, which he describes. The total number of 

 species now known from Terra-del-Fuego is 152, and the moss-flora 



* Eev. Bryologique, xii. (1S85) pp. 51-5. t Bot. Gazttte, x. (1885) p. 340. 



X Flora, Ixviii. (1885) pp. 359-64 (1 pi.). § Ibid., pp, 391-429. 



I 



