340 SUMMARY OF CURRENT RESEARCHES RELATING TO 



A New Genus of Squamariacese.* — P. Heydrich describes a new 

 genus of this Order, Poll/strata, which contains one species, P. dura, 

 with the forms nigra \iw\fnsra. It grows on corals and pieces of calci- 

 fied matter in the Tami Islands, German New Guinea. The thallus 

 spreads like a crust over the substratum. It is formed of from 2-30 

 horizontal layers, composed of several individual plants, attached in the 

 centre by a few short rhizoids. Tetraspores are described, but the cysto- 

 carps and antheridia are still unknown. It differs from already known 

 genera in the peculiar form of attachment, the covering of the old 

 thallus by new growth, and the unequally divided tetrasporangia. Its 

 nearest ally is Cruoriella. 



Dunaliella, a New Genus of Polyblepharideae.f— E. C. Teodoresco 

 has made a special study of Chlamydomonas Dunalii Colin, and finds it 

 sufficiently unlike Chlamydomonas as to form a new genus, Dunaliella. 

 He describes in detail the form of the zoospores, and the manner in 

 which it changed during certain experiments. The structure is then 

 described, the dimensions, the mode of division, and the sexual repro- 

 duction. It is noted that Dunaliella exhales a most agreeable odour 

 of violets. A full diagnosis is given of the new genus, of which the 

 salient points are : cells possessing slightly metabolic properties ; enve- 

 lope containing no cellulose, elastic and accommodating itself to the 

 changing form of the contents ; two long flagella ; multiplication by 

 longitudinal division into two individuals. The author removes this 

 genus from Chlamydomonadeaj to Polyblepharidese, placing it beside 

 Polyblepharides, Pyramimonas and Chloraster, as representing a type 

 with two flagella. 



Cladophoraceae.^ — F. Brand gives an account of his studies on the 

 mode of attachment of Cladophoracese, and describes several Polynesian 

 forms of the family. As regards the rhizoids of Cladophora and other 

 genera, he finds that they are more fully developed in marine than in 

 fresh-water species. Direct attachment by means of unaltered vegetative 

 cells occurs in C. basiramosa Schmidle only. The author treats also of 

 the fibula? of Valonia, Boodlea, etc. Several new varieties and forms of 

 existing species are described, as well as the new species Pithophora 

 macrospora, Cladophora senta, C. Tildenii, and Boodlea Romania. Clado- 

 phora composita Hook, et Harv. is removed to Boodlea. 



Plankton Investigation Round Iceland.§ — 0. Paulsen has made a 

 study of the Plankton-associations and their relations to each other and 

 to the currents. The material on which the investigation was founded 

 was collected from the Danish Government steamer and an Icelandic- 

 mail steamer. To the south of Iceland Asterionella plankton prevails 

 in early summer, and Lonyipes plankton in late summer and autumn. 

 The boundary line of plankton associations off the south-east coast of 

 Iceland is very marked, and the areas of these associations are shown on 



» Ber. Deutsch. Bot. Gesell., xxiii. (1905) pp. 30-6. 

 t Beih. Bot. CentralR, xviii. (1905) p. 215-32 (2 pis.). 

 X Tom. cit., pp. 16.1-93 (2 pis.). 



§ Merldel. Konini. for Havundersogelser. Plankton, i. (Copenhagen, 1901) r>T>. 

 1-11 (11 figs., 2 maps). 



