354 BOTANICAL GAZETTE [may 



IS, with cellulose walls, relatively scanty cytoplasm, and small, solitary nuclei. 

 The pistillate flo"wers of the capriiig in which there has been neither egg-deposition 

 nor fertilization usually do not develop farther and become atrophied. The 

 author thinks the conclusion to be inevitable that the *' stimulus'' produced by the 

 presence of the egg and larva of Blastophaga does just what is usually accom- 

 plished by fertilization, In determining not only the development of endosperm 

 but also the further growth of the ovule and of the pericarp, and the general form 

 of the fig.^J. M. C. 



Spore formation in Derbesia,— Davis^^ has published a paper treating of 

 spore formation in Derbesia, one of the Siphonales. He studied the development 

 of sporangia and the formation and germination of zoospores. The most inter- 

 esting ix)ints of the paper are the results concerning the behavior of nuclei in the 

 sporangium previous to the formation of zoospores. Many nuclei which do not 

 take part in the formation of zoospores undergo degeneration. Plastids become 

 arranged radially about the nucleus which survives the act of degeneration. 

 Including the nucleus as a center, segmentation of protoplasm takes place to form 

 the beginning of the zoospore; then the formation of the blepharoplast begins. 

 Previous to the formation of the blepharoplast, the nucleus moves from near the 

 center of the young zoospore toward the periphery. Granules around the nucleus 

 seem to move toward the periphery, where they fuse with one another to form a 

 ring which becomes the blepharoplast. Davis believes that the belepharoplast 

 of Derbesia is not a development from the plasma membrane, but from the 

 granules closely associated with the protoplasm investing the nucleus. The 

 paper closes with a discussion of the cytology of the blepharoplast and the value 

 of zoospores and gametes as taxonomic characters in Siphonales.— Snicfo 

 Yamanouchi. 



Gummosis.— RuHLAND, who had been working with the late Dr. R. Ader- 

 HOLD in the Imperial Biological Station at Dahlem upon the problem of the 

 formation of gum, has pubUshed a preliminary paper upon the physiology of 

 gum formation, =^3 promising the full account later, w^ith developmental and 

 anatomical details, in the Arbeiten of the station, A part of the paper is devoted 

 to a criticism of the latest theorj^, that of Beijerinck and Rant,^-* who hold that 

 cytolytic substances issuing from the dead cells in the neighborhood of a wound 

 cause the liquefaction of embryonal wood tissues, anomalously developed through 

 the wound stimulus. Ruhl.^nd, however, holds that, whenever such tissues are 

 produced by wounding, it is the influence of the oxygen of the admitted air that 

 determines a cessation of further division in these cells, because of the transfor- 



" Davis, B. M., Spore formation in Derbesia. Annals of Botany 22:1-20. 

 pis, I, 2. 1908. 



^3 RuHLAXD, W., Zur Physiologic der Gummibildung bei den Amygdaleen. Ber. 

 Deutsch. Bot. Gessells. 25:302-315. figs. 3. 1907. 



^^Wundreiz, Parasitismus, und Gummifluss bei den Amvgdaleen. CentralbL 

 Bakt. 11. 15:366 ff. 



