202 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of determining their identity, but that it also leads to certain scientific 

 deductions. He finds that a given reagent has the same effect on all 

 parts of the same species, be they vegetative or rhizoidal, zoospores, or 

 germinating plantlets. This fact is of great importance in the dis- 

 crimination of forms belonging to polymorphic species, and would, for 

 instance, prevent confusion between the young stages of Cladophora, 

 which resemble Gongrosira, and the true Gongrosira which reacts to a 

 different stain. Instances are given of the effect of various stains on 

 certain genera of algee, which have been soaked for 24 hours in water 

 containing a percentage of acetic acid ; all the material employed, except 

 where specially stated, was from dried plants. 



The author then describes a new species of Gongrosira, G. lacustris, 

 which he discovered during his staining experiments. A new form of 

 Coleochcete scutata, f. lobata, is also described, which the author con- 

 siders as representing merely a biological form of typical C. scutata. 

 There is no sign on it of reproductive organs, and it has not reappeared 

 in the year of writing. 



Coleochsete nitellarum.* — I. F. Lewis remarks on the structure of 

 G. nitellarum, and compared specimens collected at Long Island with 

 the original German plants described by Jost in 1895. | Lewis notes 

 two peculiarities of structure — the thin, delicate cell-walls, and the 

 broad, flat shape of the cells, and explains both these phenomena 

 by the endophytic habit of the species. He points out that his 

 Long Island plants are strictly monoecious, the antheridia being 

 usually produced in the immediate vicinity of the oogonia. The 

 mode of origin of antheridia and oogonia is described, and an 

 account given of fertilisation as observed in stained preparations. 

 The nucleus of the oogonium is central in the cell, and some- 

 what larger than the vegetative nuclei. The nucleus from the 

 spermatozoid, at first small, increases in size as it approaches the 

 oogonial nucleus, until two nuclei of approximately the same size lie 

 side by side in the centre of the oogonium. The nuclei fuse while the 

 chromatin is in the resting condition. Immediately after fusion, 

 neighbouring vegetative cells send up branches over the oogonium to 

 form the characteristic cortex of the oospore. Formation of the 

 zoospores is described, and the author shows that there is here an 

 indication of the formation of a multilocular sporangium similar to 

 that in certain Phaeophyceae. Division of the nucleus is indirect, and 

 does not take place until the single pyrenoid and chromatophore have 

 first divided. The only exception to this rule is in the case of the 

 antheridia, where the chromatophore and pyrenoid remain undivided 

 in the mother-cell. 



Algae of Mark Brandenburg-.} — E. Lemmermann publishes the 

 second part of his work on the algae of Brandenburg. He completes 

 the systematic treatment from Phormidium to Rivularia and the genera 

 of Camptotrichiaceas ; and then proceeds to deal with the class Flagel- 

 latae from a general point of view. His remarks cover the structure of 



* Johns Hopkins Univ. Calendar, Notes Biol. Lab., March 1907, pp. 29-30. 



t Ber. Deutsch. Bot. Gesell. xiii. 



X Kryptogamen-Flora Mark Brandenburg, iii. part 2 (1907) pp. 129-304. 



