i9o8] CURRENT LITERATURE 357 



in others it is replaced by a fusion of ascogonial nuclei in pairs. After either 

 process the ascogonium becomes septate, and each of its cells gives rise to ascoge- 

 nous hyphae. In the ascus two nuclei fuse, and three successive divisions result 

 in eight spores, which subsequently become multmucleate. The authors regard 

 Aspergillus as a primitive type of Ascomycetes, from which most of the others 

 can be derived; and suggest that the Ascomycetes are related to the Basidiomy- 

 cetes and the Florideae. — J. M. C. 



Adventitious buds in leaves of Gnetum— In plants of Gnetum Gncmon L., 

 grown in a hothouse of the Botanic Garden at Utrecht, the tips of the leaves 

 regularly produced adventitious buds. Van Beusekom3^ finds that these buds 

 are formed as a result of the attacks of a scale insect, Aspidirtus dktyospcnm 

 :^Iorg., a species with a world-wide distribution in the tropics and in hothouses. 

 The punctures of this insect result in yellow vesicles at various points on the leaf, 

 and one or more near the apex stimulate the development of endogenous callus 

 buds. The author "explains " the appearance of the buds in the apical part alone 

 of the leaf, by assuming that "the small wound causes an afflux of ""^nent 

 matter in an apical direction," and that this necessarily stops just beyond the 

 apical wound's. Of course this is a mere assumption, the like of which is often 

 made, but it would puzzle any of those who use it to show how "an afflux ot 

 nutrient matter" could occur before growth actually begins.— C R. B. 



Conjugation and germination in Spirogyra.— An examination by Trondle^' 

 of several thousand zygospores, some sectioned and some observed entire, con- 

 firmed the current account that the two nuclei remain separate for some time ai e 

 the zygospore is formed. In Spirogyra communis the sexual nuclei fuse tv^o_ ^ 

 three weeks after the formation of the zygospore. Two successive "^■'to^^^ S'^'"- 

 rise to four nuclei, and a subsequent fusion of two of these nuclei as descnbea oy 

 Chmielewski, do not occur. The male chromatophores in the zygote disorganize 

 in about fourteen days after conjugation, leaving only the chromaiophore. oi x 

 female gamete. The writer also talks about a reduction of the heredrtarj ma 

 referring,to the nuclear material, but nothing in the text or figures indicates ^^y 

 counting of chromosomes or any study of the mechanism of '■^^"^^J'' . 

 paper contains a detailed account of the chemical changes occurring g 



development of the zygospore.— Charles J. Chamberlain. 



Plantae Lindheimerianae.-To students of the Texan flora E^'GE^^^;-^^ ^^^"^^ 

 Gray's Plantae Lindheimerianae, in two parts, is a classic i ""^ ^ ^^^ 

 that all of the collections of this pioneer botanist were not published and cU. , 



and the rich remnant came into the possession of the Missouri Botanical 



3^ VAN Beusekom, Jan, On the influence of wound ^^^'^^^\''" *^ ^^T N4erl. 

 adventitious buds on the leaves of Gnetum Gnemon L. Recuei 



4: pp. 27. ph. J. 1907 



3J 



Trondle, a., Ueber die Kopulation und Keimung von Spirog}Ta. 

 65:188-216. pis, 5. 1907. 



Bot. Zeit. 



