212 SUMMARY OF CURRENT RESEARCHES RELATING TO 



rhizoids are often replaced by new ones that form within them. 

 4. Fungi are prevalent in the compact tissue of the thallus. They both 

 enter and may pass out through the rhizoids. No " pseudoparenchyma " 

 was found. 5. The secretion of mucilage seems to have nothing to do 

 with the " protection " of the growing point, but to be most pronounced 

 about the egg and the antheridia. 6. Pitted cells show no tendency to 

 become trachea-like. 7. The origin of air-chambers in the thallus and 

 receptacles is schizogenous. The horizontal increase in the size of the 

 chambers is due to the tearing of the tissues. The pore of the 

 chambers of the thallus and of the antheridial receptacle is simple, but 

 that of the archegonial receptacle has an elaborate margin. 8. The 

 development of the sex organs follows the Marchantiales type. The 

 archegonia form early in the history of the receptacle and parallel the 

 increase in size of the receptacle by great increase in length of the neck. 

 Following fertilization an exceedingly massive venter is developed 

 about the embryo. 9. Five archegonia may begin to develop on one 

 receptacle, but no more than three come to maturity. 10. The 

 condition of the cells of the foot and of the adjacent parts of the 

 thallus indicate the parasitic nature of the sporogonium. No elatero- 

 phore appears. 



Podomitrium.* — D. H. Campbell gives an account of the morphology 

 and systematic position of Poilomitrium. There are two species — 

 P. Fhyllanthus in Australasia, and F. malaccense in the Malay region. 

 The anatomy of the thallus accords with Blyttta, and in most respects 

 the author finds the genus to approach most nearly to Bhjttia, but not 

 in the position of its reproductive organs, nor in the presence of a 

 definite foot in the sporophyte, and of a distinct elaterophore ; moreover 

 it has a different method of dehiscence. Cavers's suggestion that the 

 families Aneurace?e and Blyttiacete should be combined is good ; for 

 no constant characters are available for distinguishing them from one 

 another. 



Mosses of Lake Takern in Sweden.f — H.W.Arnell and C. Jensen 

 publish the result of their investigation of the moss vegetation of Lake 

 Takern in Oestergotland, Sweden. In the middle of last century a 

 sinking of the water level took place ; and when lately the question of 

 a further sinking arose, an investigation was made as to the natural 

 phenomena which would be thereby endangered. The authors were 

 requested to undertake the mosses. Their report deals principally with 

 the ecological conditions. The moor adjoining the lake is also dealt 

 with, the moss vegetation being totally different. In the systematic 

 treatment of the species recorded, the Aduncum group of Amblystegium 

 receives detailed attention. 



Mosses of Madagascar.! — F. Renauld and J. Cardot have issued 

 the text of their great work on the mosses of Madagascar, the atlas of 



* Amer. Journ. Bot., ii. (1915) pp. 199-210 (figs.). 



t K. Svenska Vetensk. Sjon Takern faun, flor., i. (1915) pp. 1-37. See also Bot. 

 Centralbl., cxxix. (1915) pp. 669-71. 



I A. and G. Grandidier, Histoire Phys. Nat. Madagascar, xxxix. (Paris, 1915) 

 564 pp. 



