488 SUMMARY OF CURRENT RESEARCHES RELATING TO 



described for the genus. G gracilipes varies in length from 80-480 ^ 

 and G. cylindricum from 24-430/*. Both species are described in detail 

 and figured. They both form hosts to a fungus, which produces con- 

 siderable modification in their shape. 



Wittrockiella, a New Genus.* — N. Wille describes and figures a 

 new genus of Algre, founded on a species which he discovered growing 

 on the ground close to the sea in Norway. The plant, which he calls 

 Wittrockiella paradoxa, is distinguished by the outermost cells of the 

 clump of filaments being of a bright golden orange colour, while the 

 inner cells are bright green. The filaments are united into a fairly firm 

 gelatinous mass. The cells contain one parietal, net-like chromatophore, 

 in the meshes of which are the pyrenoids, while in the parietal proto- 

 plasm inside the chromatophore lie some fourteen nuclei. Another 

 peculiarity of this alga is that the orange-yellow cells on the surface of 

 the thallus put forth hairs, which may attain a considerable length. 

 These are regarded by the author as probably organs of absorption. 

 W. paradoxa possesses two kinds of reproductive organs, akinetospores 

 and aplanospores. The former may germinate at once in one of several 

 different ways, or they may pass through a period of rest, for which 

 they are specially adapted by their thick wall. They are also par 

 excellence adapted for reproducing the plant in the place in which they 

 are formed ; for they are heavy, and so surrounded by a slimy mem- 

 brane that they are not easily detached from the mother-thallus. On 

 the other hand, the aplanospores travel quite easily to considerable 

 distances, and, having a thin membrane, are probably incapable of 

 going through a resting stage. They are quite possibly reduced non- 

 ciliated swarmspores. No zoosporangia nor zoospores were observed. 

 As regards the systematic position of this alga, it is regarded by the 

 author as forming the type of a new family of Chsetophorales near 

 Chroolepidacea?, described as Wittrockiellaceag. 



Life-history of Trentepohlia umbrina.f— K. Meyer writes an 

 account of Trentepohlia umbrina, and describes a form, which he found 

 growing with it, bearing pedicellate zoosporangia. This the author took 

 at first to be T. uncinata, but later, finding several essential points of 

 difference, he has called it T. pseudo uncinata. In most details, however, 

 it so closely resembles T. umbrina, that he is disposed to think it may 

 be a form of that species, and that T. umbrina, like T. bisporangiata 

 Kar. and others, possesses two kinds of sporangia, which are probably 

 gametangia and zoosporangia. The life-history of T. umbrina is 

 described, with the condition of its growth ; the author disbelieves in 

 the parasitism of the plant. 



Development of Oocystis.J — N. Wille has made a study of 

 Oocystis isubmarina Lagerh., and describes its life-history, thus com- 

 pleting our knowledge of that plant. Material of it was found in 

 large quantities near Arendal, in Norway, in July l'J07. The author 

 describes the size and form of the cells, the chromatosphore, pyrenoids, 



* Nyt Mag. Naturv., xlvii. (1909) 21 pp. (4 pis.). 



1 Bot. Zeit., Ixvii. (1909) pp. 25-43 (2 tabs., figs, in text). 



% Ber. Deutsch. Bot. Gesell., xxvia (1909) pp 812-22 (1 pi.). 



