ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 219 



rotting of tubers attacked is not directly due to the fungus, but to 

 accompanying Bacteria. They note also in this fungus the absence of 

 differentiated haustoria, a peculiarity confined to this one member of 

 the Peronosporeas, it being also the only one that can live as a 

 saprophyte. 



The Genus Harpochytrium in the United States.* — G. F. Atkinson 

 describes in detail the plant that forms the basis of his paper, which he 

 found growing on Spirogyra. The organism is composed of a long 

 slender more or less fusoid and usually curved sporangium. It is 

 pointed at the base where it pierces the wall of the host-cell. Zoospores 

 are formed in the parasite which escape at the tip, and after swarming 

 attach themselves to the host. After the zoospores have escaped, a new 

 sporangium grows out within the old one from the sterile basal part. 

 Atkinson found that the plant belonged to the genus Harpochytrium 

 Lagerh. He considers also that the genus Fulminaria Gobi is syno- 

 nymous, and that the plant RhaMium acatum of Dangeard is also a 

 member of the same genus. He gives his reasons at length for this 

 grouping. There are three species known, two of them found also in 

 Europe. They are all parasitic on some green alga. 



Structure and Classification of the Phycomycetes.f — C. E. Bessey 

 holds that the Phycomycetes do not form a natural group, that they are 

 derived though fungal modification from different algal types, and that 

 in any scheme of classification the algae must be considered first. He 

 claims that they come from three different groups of algae : the Synchy- 

 triacea? from the Protococcoideaa ; the Chytridiacese from or near the 

 Botrydiaceaa, in the order Siphonese ; and the Saprolegniaceaa from or 

 near the Vaucheriaceae, also in the order Siphoneas. The other members 

 ef the Phycomycetes are derived from the Saprolegniaceaa, with the 

 exception of Monoblepharis, which suggests the (Edogoniaceae. In all 

 these classes the fungi or " hysterophytes " are parasitic or saprophytic, 

 and show more or less morphological degradation. Bessey follows the 

 order laid down ; he gives the key to the combined families of algas and 

 fungi, and gives a descriptive account of each of the fungal genera. 



Critical Notes on Exoasceae.J — P. Sadebeck reviews the species of 

 Taphriaa and Exoascus, noting the points in which they differ and the 

 variations within the different species. Points to be noted are the per- 

 sistence of the mycelium in the host from year to year, the formation 

 of a hymenial layer, the depth to which the hyphae penetrate the leaf, 

 and the different forms of the asci and of the basal cells. He makes 

 a comparison between these genera and Endomyces. 



Mould Yeasts.§ — M. Hartmann experimented with a species of 

 Torula which he isolated from colonies of Mucor amylomyces, where it 

 formed slight elevations on the surface of the Mucor growth, and which 

 he named T. colliculosa. Young cultures could not ferment maltose, 



* Ann. Myco 1 ., i. (1903) pp. 479-502 (1 pi.). 

 t Trans. Amer. Micr. Soc, xxiv. (1903) pp. 27-54 (1 pi.). 

 X Ber. Deutscli. Bot. Ges., x. (1903) pp. 5S9-46. 



§ Wochenschr. f. Braueri, xx. (1903) pp. 113-14 (5 figs.). See al6o Ann. Mycol., 

 i. (1903) p. 567. 



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