682 SUMMARY OF CURRENT RESEARCHES RELATING TO 



To this critique Herr Oltmanns * again rejoins, maintaining that 

 even in the case of Polytrichum and Mnium the power of conduction of 

 the stem is so small that only in an atmosphere of at least 90 per 

 cent, relative moisture is it suf&cient to meet the consumption. The 

 internal conduction must therefore in any case be of very subordinate 

 importance. 



Pottia Giissfeldti, a new Moss.j — Under this name, Herr K. 

 Schliephacke describes a new species of moss from the mountains 

 of the Argentine Eepublic, of interest as belonging to a European 

 type, and replacing in that country the P. latifoUa of our Alps. The 

 author dissents from Venturi's proposal to establish from P. latifoUa 

 a new genus Stegonia dependent on the peculiar character of the cells 

 and nerve of the leaf; but proposes, on the other hand, to form under 

 the same name a subgenus of Pottia which shall comprise the two 

 species P. latifoUa and Giissfeldti. 



Elaters of Hepaticae.:): — M. Leclerc du Sablon defines the part 

 played by the elaters in the dissemination of the spores of the 

 Hepaticse. He points out the resemblance in the structure and the 

 mode of dehiscence of the sporogonium of Hepatic se and the anther 

 of flowering plants, and describes the former in detail in the case of 

 Pellia epiphylla, Calypogeia Trichomanis, and Frullania dilatata. As 

 the elater dries it contracts considerably, and the coils of the spiral 

 become closer, expanding again on moistening. The intervals be- 

 tween the coils of the spiral contract more than the spirals themselves, 

 which are lignified. In addition to their contraction, the elaters also 

 change their position when the sporogonium dehisces; before de- 

 hiscence they are parallel, afterwards divergent ; and this last is the 

 chief agency in violently separating and dispersing the spores. 



Algae. 



Protoplasmic Continnity in the Fucace8B.§ — In continuation of 

 his previous observations on the continuity of protoplasm from cell 

 to cell in the thallus of the Floridese, |[ Mr. T. Hick now describes 

 the same phenomenon in several species of FucacoEe, especially Fucus 

 nodosus (Ascophyllum nodosum), F. vesiculosus, and F. serratus. In the 

 first species named, in the cortical layers and in the filaments of the 

 central tissue, the protoplasm appears to run uninterruptedly from 

 cell to cell in the longitudinal direction. 



At the ends of the cells, i. e. at the point where two adjacent cells 

 are united, there is an annular thickening on the internal wall not 

 unlike a strongly developed ring of an annular vessel. The material 

 of which this ring is composed differs from that of the cell-walls in 

 not dissolving or undergoing gelatinization under the influence of 

 reagents. It seems to resist alike the action of the strongest acids 



* Op. cit., iii. (1885) pp. 58-62. 

 t Ber. Deutsch. Bot. Gesell. ii. (1885) pp. 461-2. 

 i Bull. Soc. Bot. France, xxxii. (1885) pp. 30-4. 

 § Journ. of Bot., xxiii. (1885) pp. 97-102 (1 pi.). 

 II See this Journal, iv. (1884) p. 101. 



