210 Morphologie etc. — Varietäten etc. 



Thoday (Sykes) M. G., The Female Inflorescence and 

 Ovules of Gnetum africanum, with Notes on Gnetum scan- 

 dens. (Ann. Bot. XXV. p. 1101 — 1135. pl. 86-87. 16 Textfigs. 1911.) 



The vascular System of the female inflorescences and flowers of 

 G. africanum and G. scandens and of the male inflorescence of G. 

 scandens, and the structure of the seed coverings in both species 

 are described in great detail. The method of vascular supply to the 

 Single female flower in G. africanum is compared with that to the 

 axillary inflorescence in Bennettites, and the outer integument of 

 G. africanum is shown to resemble that of B. Morierei in histology. 

 The greater portion of the ovule is developed by intercalary growth 

 below the free portion of the seed coverings. The micropylar tube 

 becomes closed after fertilisation and the closing tissue forms a 

 lignified rod. This is compared with the nucellar beak of B. Morierei. 



The ovule of Gnetum is regarded as more primitive than that 

 of Welwitschia. 



The author concludes that the comparison of the seed charac- 

 ters of Welwitschia and Gnetum with those of Bennettites, and of 

 such Pteridosperms as Lagenostome, and of the recent group of 

 the CycadSj renders is probable that all these plants derive their 

 origin from common ancestors. 



Agnes Arber (Cambridge, England). 



Bean, W. J., Graft-hybrids. (Kew Bull. VI. p. 267— 269. 2. pl. 1911.) 



Short notes on the behaviour of specimens of the Crataego- 

 mespilus hybrids grown at Kew, illustrated b}^ very good photo- 

 graphs showing the Variation in the shoots borne by one specimen 

 of C-m. Dardari. Another photograph shows C-m. Asnieresi in flower. 



R. P. Gregor}'. 



Blackman, V. H., The Nucleus and Heredity. (New Phytol. 

 X. p. 90-99. 1911.) 



The author briefly reviews the grounds upon which the nucleus, 

 and especially the chromatin, has been identified as the idioplasm 

 of Nageli, calling attention, among other things, to the observa- 

 tions of Strasburger, Nawaschin and himself, which show that 

 in certain Angiosperms the male fertilising dement "is in no sense 

 a cell but is a mere naked nucleus". After examining some of the 

 criticisms which have been levelled against this view, he gives an 

 outline of the results obtained by Herbst, Boveri, Godlewski 

 and others in their experiments upon Echinoderm larvae. The bearing 

 of the evidence as to the occurrence of amitosis upon the general 

 theory is shortly discussed. The author concludes that, in the case 

 of the higher organism at least, this theory of the monopoly of the 

 nucleus in the transmission of inherited characters still holds the 

 field. Botanists who are unfamiliair with zoological literature will 

 be grateful to the author for an introduction to the very important 

 data gained from zoological studies. R. P. Gregor)-. 



Gregory, R. P., The Forms of Flowers in Valeriana dioica L. 

 (Journ. Linn. Soc. (Bol.) XXXIX. p. 91—104 and one double plate. 

 1909.) 



In 1877 H. Muller (Kosmos, Bd. II, p. 131) described four forms 



