630 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Finally two new genera are described, each containing one species, 

 Planctonema Lauterborni and Dictyosphceriopsis palatina. 



Nuclear Stains for Fresh-water Algae.* — Catherine Hillesheim 

 has tried various fixing and staining agents for species of Spirogyra, 

 Zygnema, Microspores, and Hormiscia zonata ; also for species of Clado- 

 phorct and for Hydro diet yon reticulatum. The best fixing agent was 

 chromic acid, and the most successful stain was a mixture of borax and 

 ammonia carmine, in equal quantities. 



Dictyosphseria favulosa.| — Caroline M. Crosby has been able to 

 add to our previous knowledge of this species in certain details. She 

 regards Dictyosplmria as a low type of Valoniaceas because of (1) the 

 primitive, closely appressed branched system, and (2) the well-developed 

 rhizoids. 



Under histology she deals with the structure of the " cell-walls " : 

 the " inner cell-strengthening," which she describes in detail ; and the 

 "external cell-strengthening" by means of haptera. The origin and 

 development of the haptera are then described, as well as the rhizoids. 

 Under cell-contents, the author treats of the endochrome, pyrenoid, 

 starch-grains, oil-drops, and cell-sap. 



Stapfia cylindrica4 — C. J. Brand finds this alga on the north 

 shore of Lake Superior and compares it with the plants of Nordstedt, 

 Wittrock, and Lagerheim No. 1362, distributed under the name of 

 Tetraspora cylindrica Ag. f. enteromorplwides Lagerheim. He also com- 

 pares it with the specimens distributed by Eabenhorst as No. 2244, 

 Tetraspora cylindrica, and draws up a diagnosis of the Lake Superior 

 plant. 



Algological Notes.§ — Under this heading N. Wille continues the 



^record of his studies on the lower alga?. Note ix. contains an account 



of a new Garteria, C. subcordiformis, found in fresh-water puddles in 



places where fish are dried near Aalesund in Norway. Other species 



belonging to Chlamydomonas and Brachiomonas were found with it. 



The genus Sphcerdla is the subject of note x. This is synony- 

 mous with Ho&matococcus Ag. and the author points out the great 

 difficulty of distinguishing the genera Hamiatococcus Ag..(= Sphccrella 

 Somrri., Chlamydccoccus A. Br., &c.) and Chlamydomonas Ehr. He is 

 inclined to regard as an important character the presence or absence of 

 pseudopodia, and to reject any distinction founded on hamiatochrome. 

 He separates Sphozrella nivalis Somm. from Hmnatococcus and places it 

 in Chlamydomonas. For the former genus he draws up a generic 

 diagnosis and places in it the two species, H. pluvialis Flotow and 

 H. Butschlii Blochmann. For both species he gives full synonymy and 

 description. A list follows of six species which the author excludes from 

 Hcematococcus, with references and remarks. 



Note xi. contains a morphological and systematic account of the 

 genus Chlamydomonas. The various polymorphic stages of the species 



* Minnesota Bot. Studies, iii. (1903) pp. 57-9 (1 pi.). 



t Tom. cit., pp. 61-70 (1 pi.). % Tom. cit., pp. 71-4 (1 pi.). 



§ Nvt Mag. Naturvidenskab., xli. (1903) pp. 89-185 (2 pis.). 



