72 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Lophozia Hatched and L. Baueriana.*—Y. Schiffner discusses the 

 two species of Lophozia, L. Hatcheri and L. Baueriana, which he has 

 studied from original specimens, and decides that the species are not 

 identical, notwithstanding their remarkable likeness. The two nearest 

 habitats of the respective species are 11,000 kilom. apart and separated 

 by the tropical zone. The extraordinary morphological resemblance 

 may be explained in three ways:— 1. Both are of common origin, the 

 original ancestor having been distributed over an enormous area, but 

 owing to geological and climatic changes it has died out in the inter- 

 mediate regions. 2, Carriage of the spores or gemmae, which is only 

 possible in species of Riccia which inhabit water. 3. Convergence,, 

 which is probably the solution of the problem under consideration. 



Thallophyta. 

 Algae. 



(By Mks. Ethel S. Gepp.) 



Biology of Algae. — G. S. West publishes the first volume of a 

 treatise on Algtii in which he gives a biological account of all the Alga? 

 included in the Myxophycefe, Peridiniete, Bacillarieai and Chloro- 

 phyceas, both fresh-water and marine. In a future volume it is proposed 

 to give a complete systematic account, with illustrations, of all the British 

 Fresh-water Algje, with the exception of Desmids and Diatoms. In the 

 present work the chief space is allotted to the Chlorophyceae. These 

 are arranged under four sections — Isokontse, Akontse, Stephanokontae, 

 Heterokontae. Under Isokontae are six orders : — Protococcales, includ- 

 ing all the unicellular and colony-forming types ; SiphonaJes ; Siphono- 

 dadiahs ; UJvaUs ; Schizogoniales ; UJotrichaJes. The Akontie comprise 

 the Conjngatse ; the Stepbanokontte, the (Edogoniales ; and the Hetero- 

 kontffi comprise the orders Heterococcales, Heterotrichales, and Hetero- 

 siphonales. A chapter is devoted to the occurrence and distribution 

 of fresh-water Algte, describing Sub-aerial Associations, Associatious 

 of Irrorated Rocks, and Aquatic Associations. 



Structure and Mode of Life of Hormidium flaccidum. |— Alma 

 Piercy gives a general account of the life of a form of Hormidium 

 Jiaccidum A. Braun in its native habitat. The survival of the vegetative 

 filaments throughout successive seasons of the year is described, and 

 their modification during drought, chiefly in the accumulation of 

 refractive granules, and in changes of the longitudinal walls and septa. 

 A detailed description is given of the two common methods of repro- 

 duction, viz. : (1) transverse splitting of the filaments- at the septa ; 

 and (2) production of aplanospores. Regarding (1), a general breaking 

 up of the filaments into isolated cells or few-celled pieces has not been. 



* Oesterr. Bot. Zeitschr., Ixvi. (1916) pp. 83-8 (figs, in text). See also Bot> 

 Centralbl., cxxxiv. (1917) p. 187. 



t Algse. Cambridge University Press : (1916) i., x and 475 pp. (271 figs.). 

 X Ann. Bot., xxxi. (1917) pp. 513-37 (figs.). 



