OCTOBEE 19, 1900.] 



SCIENCE. 



583 



A study of the embryology of Viburnum 

 prunifolium is interesting because the ovules 

 of two of the locules of the tricarpellary 

 ovary early become aborted, while the sin- 

 gle ovule of the remaining locule develops 

 normally. The functional ovule which oc- 

 cupies the largest locule attains the ana- 

 tropous condition before the abortive 

 ovules, from three to five in number, in 

 each of the smaller locules, begin their 

 development. The abortive ovules never 

 become anatropous because of the me- 

 chanical conditions arising from lack of 

 space in the locules, which are soon 

 filled by the developing nucelli. The 

 archesporial cell of the abortive ovules 

 either divides to form two megaspores, 

 each of which by successive divisions forms 

 eight nuclei, or else it forms the em- 

 bryo-sac directly, which in its completed 

 state contains sixteen nuclei. The nuclei 

 are similar in appearance and fail to be- 

 come difierentiated and arranged accord- 

 ing to the usual plan of embryo-sacs. 

 These abortive embryo-sacs persist until 

 after fertilization, when they begin to dis- 

 integrate. The archesporial cell of the 

 functional ovules divides to form two mega- 

 spores, the lower of which usually en- 

 larges to become the embryo-sac. The 

 polar nuclei fuse before anthesis. The an- 

 tipodal apparatus, which consists of three 

 large cells, increases in size after the forma- 

 tion of the endosperm nucleus until the 

 differentiation of the egg apparatus, when 

 it begins to disintegrate. The nucellar tis- 

 sue, small in amount, disappears as the 

 embrj'o-sac develops. The endosperm nu- 

 cleus divides rapidly, after fertilization, by 

 free-cell division. A bulky endosperm is 

 soon formed and is surrounded by the in- 

 tegument ; integumental cells infringing 

 upon the endosperm constitute, as in cer- 

 tain other gamopetalse, a tapetum, which 

 does not disintegrate. An accumulation of 

 food near the embryo is to be noted. 



On the supposed Polymorphism of Eremos- 

 phaera viridis : By G. T. Mooee. 

 This unicellular alga has been the subject 

 of considerable speculation as to its life his- 

 tory and consequent systematic position. 

 De Bary who first described it, thought it 

 might be a desmid, while De Wildeman be- 

 lieved it was more probably a zygospore than 

 a desmid itself. De Toni suggested that 

 Eremosphdera was nothing more than a pro- 

 thallial condition of some fern, and Chodat, 

 one of the most recent observers of this plant, 

 has made out a remarkable case of poly- 

 morphism ; finding stages resembling Pal- 

 mella, Schizochlamya, Centrosphcera and other 

 genera, in addition to the formation of zoo- 

 spores. The author of the present paper has 

 attempted, by means of pure cultures, to 

 demonstrate the true affinities of the plant 

 and after studies covering several years, 

 comes to the conclusion that Eremosphoera 

 has no other method of reproduction than 

 that of simple division, and that it cannot 

 be related to any of the numerous genera it 

 has been supposed to resemble. The paper 

 will be published in full in the Botanical 

 Gazette. 



Note on Arceuthobium : By Hebmai«"n von 



SCHEENK. 



The speaker described the method of seed 

 distribution of these mistletoes, and the 

 germination of the seed. Some large brooms 

 formed by Arceuthobium pusillum on the 

 black spruce were shown, and the occur- 

 rence of this species on the red spruce in 

 the southern Adirondacks was reported. 



The Origin of the Tannin in Galls : By Henet 



Keabmee. 



In presenting some notes on the origin of 

 tannin in galls the author limits his obser- 

 vations to examinations of the common 

 ' ink ball ' or ' oak-gall ' which is produced 

 on Quercus coeeinea Wang, and Q. imbriearia 

 Michx, probably by Cynips acioulata O. S. 

 The galls are nearly globular in shape and 



