RECENT ADVANCES IN SCIENCE 33 



frequent on the basal regions of the plant and after the second 

 week of the flowering period. 



The variation in the different whorls of the flower has 

 been studied in further members of the Ranunculaceae by 

 Sahsbury (Ann. Bot. January). The two species investigated, 

 viz. Anemone apennina and Clematis vitalba, show the periodic 

 type of meristic variation " curve " even more strikingly than 

 some of the species previously studied. In the former there 

 is an obvious correlation between the number of perianth 

 segments and the number of stamens. " Branched " carpels 

 were observed in several examples of both species. 



M. Ikeno {Rev. Gen. de Bot.) has cultivated a race of Plan- 

 tago major termed contracta which is recessive to the so-called 

 type. When these recessives were self-fertihsed, however, 

 the offspring showed a certain number (0*5-10 per cent.) 

 of reversions to the type. On self-fertihsing the reversions 

 they proved to be heterozygous and segregated in the normal 

 manner into var. typica and var. contracta. 



Yampolski (Amer. Jour. Bot., December) deals with the sex 

 intergrades of Mercurialis annua. At the one extreme are 

 purely female plants, at the other purely male, whilst in be- 

 tween are a series of which, in the author's cultures, some were 

 prevailingly male with from i to 47 female flowers, other pre- 

 vailingly female with from i to 32 male flowers. The male 

 flowers bear normally 8 stamens, and the female a bi- or tri- 

 carpellary ovary, but hermaphrodite flowers also occur with 

 only I to 6 stamens in which both types of sporophyll appear 

 to be functional. 



Of 50 plants raised in Fi from a prevailingly female parent, 

 all showed the same sex-tendency, and this was maintained in 

 F, and Fi. Similarly the offspring of prevaiHngly male 

 plants were prevailingly male, whilst crosses between the two 

 strains yielded a sex ratio of approximately 1:1. The results 

 indicate that neither the male nor female gamete can be re- 

 garded as heterozygous to sex. 



In a further paper {Amer. Jour. Bot. January) deahng with the 

 general question the same author suggests that there may be 

 graded potencies for both types of gamete. 



The role of the endosperm has been the subject of numerous 

 experimental investigations, and those of Van Tieghem and 

 Brown and Morris, in particular, have led to the view that 

 the endosperm, though an aid, is not essential for germination, 

 and that, in grasses at all events, it is a purely passive store- 

 house of food. 



Andronescu {Amer. Jour. Bot.), experimenting upon Zea 

 mats, confirms the conclusions of earlier workers, but the chief 

 interest of his results is due to the fact that the plants were 



