• ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 211 



jS. Martensii, S. Kraussiana, S. chrysocaulos and S. chrysorrhizos, tend to 

 show that the presence of the dorsal flap in the sporophylls of Selaginella 

 is not primitive, but has been evolved in the genus 



• Asplenium Seelosii Leyb.* — L. Diels discusses the ecology of 

 Aspleninm Seelosii, having studied the earlier development stages in the 

 Dolomites. The hairs of the primary leaves consist of cylindrical cells 

 of equal diameter, and contain chlorophyll grains ; they serve for the 

 absorption of dew. A necessary condition for the development of the 

 fern is the association of algae and moss, namely, Eadadium verticillatum 

 and colonies of Nostoc in the clefts of the Dolomite. The young plant 

 turns its leaves to the illuminated surface of the rock-wall, the orienta- 

 tion being brought about by means of the stipes. It curves itself 

 downwards in the upper third, and thereby brings the lamina into the 

 light. A plant 6 cm. high has a root system which penetrates 20 cm. 



■deep into the rock. The luxuriantly produced spores are mostly distri- 

 buted by small animals (wood-lice). The dead fronds reiiiain long on 

 the plant. The prothallium grows in clefts containing clay, the fronds 

 accommodating themselves to the dry rock surface. The species appears 

 to "have a defined habitat between Etsch and Tagliamento. Since the 

 species belongs to the genetic Mediterranean element of the Alpine flora, 

 it is possible that it occurs as Christ states in the Catalonian Pyrenees. 



Bryophyta. 

 (By A. Gepp.) 



European Hepaticae.f — K. Miiller publishes a further part of his- 

 Liverworts of Germany, Austria and Switzerland. In it he deals with 

 the puzzling genus Cephaloziella, following Douin's grouping, but without 

 according generic rank to the separate groups. Critical remarks are 

 given for G. striatula, C. Limprichtii, C. Bryhnii, C. bifidioides, and 

 C. dentata. A new diagnosis and figures are given of C. ohtusa, an 

 ally of C. integerrima. Under Calypogeia it is shown that C. paludosa 

 is in no way worthy of specific rank, and that the sporogonium-valves of 

 G. sphagnicola are liable to many variations of cell-structure. Under 

 Pleurozia it is stated that the sterile tubular-organs are also found on 

 the European species. In this part begins Section viii of the whole 

 work, which is devoted to the geographical and ecological distribution 

 of the European liverworts, tip to the present time lack of definite 

 knowledge as to the limits and true relations of the various species, as 

 well as their general and European distribution, has prevented a complete 

 treatment of their distribution as a whole. The author shows that 

 liverworts, like the higher plants and the ferns, have strictly Hmited 

 areas, and that only a few are cosmopolitan. One of the most important 

 results of this study of distribution is the conclusion that liverworts 



* Verb. Bot. Ver. Prov. Brandenburg, Ivi. (1914) pp. 178-83. See also Bot. Cen- 

 tralbl.. cxxxiv. (1917) p. 330. 



+ Rabenborst's Kryptogamen-Flora, Band. vi. : Lebermoose. Leipzig : 1916, 

 pp. 785-848 (figs.). See also Bot. Centralbl.. cxxxiv, (1917) pp. 845-7. 



