ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 233 



Phseothamnion confervicolum.* — F. L. M'Keever records this alga 

 for the first time in the British Isles. He found it among algaa collected 

 from the Elf Loch on the Braid Hills, Edinburgh, growing on Lemna 

 minor and other aquatic Phanerogams. 



Myxophyceae.f — J. E. Tilden publishes a book in which she brings 

 together the specific descriptions of all the blue-green algse so far known 

 to exist in North America and the adjacent regions (including the Arctic 

 regions, Alaska, Greenland, Canada, Newfoundland, Labrador, the 

 United States, Lower California, Mexico, Central America, the Bermudas, 

 the Bahamas, the "West Indies, and the Hawaiian Islands). Simple keys 

 are furnished for the families, genera and species, and many of the 

 species are figured. Specimens from exsiccatas are quoted and localities 

 given. Finally there is a glossary and a list of hosts and associates. 



Symbiotic Alga. — J. Horejsi has investigated the alga which 

 grows in the dichotomous branches of the roots of Cycas revoluta, 

 Anabsena cycadearam Reinke. According to the author, the alga is the 

 cause of the abnormal dichotomous growths of certain roots. It shows 

 a regular annual periodicity, the symbiosis lasting from the beginning 

 of autumn to the end of spring. The alga enters through the lenticels 

 of the roots and penetrates into the meristeinatic apical tissue, stops 

 further growth and causes dichotomy to take place. Only the vegetative 

 apices are free from the alga, which is strongly heliotropic and belongs 

 probably to Anabsena. A detailed description is given of the alga and 

 its life-history. The author considers that the alga probably takes up a 

 certain amount of the products of assimilation from the host and that 

 the roots in return take from the alga their products of nitrification. 

 The alga is able to maintain, and even to form, its chlorophyll in very 

 feeble light. The author has succeeded in cultivating the alga in soil 

 extract, in alkaline fluid, and in agar. 



Loew, 0. Uber die Wirkung von Strontinmsalzen auf Algen. (On the effect of 

 Btrontium salts on algae.) Flora, neue Folg., cii. (1911) pp. 96-112. 



Fungi. 

 (By A. Lobrain Smith, F.L.S.) 



Research on Cladochytriacese.§ — Rene Maire and Adrien Tison 

 followed the development of Urophlyctis hnnisphserica on Carum incras- 

 satum, and describe it fully. The point where the cell of the host has 

 been infected by a zoospore remains in contact with the exterior ; a 

 small vesicle is formed in the cell which buds and forms other vesicles ; 

 the final terminal vesicle becomes the chronisporocyst. The authors 

 noted no case of nuclear fusion ; the reproduction is entirely asexual. 

 They found the same course of development in Physoderma Oerhartii on 

 Glyceriajfuitans. The three genera Urophlyctis, Physoderma, and Clado- 

 ckytrium, form, they find, a homogeneous group with asexual reproduc- 

 tion by the formation of chronisporocysts. 



* Ann. Scot. Nat. Hist., No. 77 (1911) pp. 57-8. 



t Minnesota Alg?e, vol. i. Report of the Survey Bot., ser. 8 (1910) iv. and 328 pp. 

 (20 pis.) \ Bull. Int. Acad. Sci. Boheme (1910) 10 pp. (24 figs.). 



§ Comptes Rendus, clii. (1911) pp. 106-7. 



