304 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Bellevallia Webbiana, and we should thus have clear examples of a 
certain number of chromosomes of different forms resulting from trans- 
verse division and belonging to the series 2, 4, 8, 16, 32, . . . and to a 
certain number of similar chromosomes belonging to the series, 3, 6, 
12, 24, . . . The author believes that the artificial selection of 
hyacinth-cultivators is tending to produce results similar to those 
brought about by natural selection — viz. the disappearance of races with 
16 chromosomes and the exclusive preservation of the large and strong 
races with a greater number of chromosomes. 
The paper is followed bv a review of the literature (pp. 118-43) deal- 
ing with previous observations on the cytology of Hyacinthus orientalis , 
which has proved a good subject for study. S. Greves, 
Structure and Development. 
Vegetative. 
Vessels of the Gnetalean Type in Angiosperms. — R. C. Mac- 
DuffiE ( Bot . Gaz., 1921, 71 , 438-45, 4 pis.). An account of the 
vessels of a few woody Angiosperms and also of herbaceous and climbing 
plants belonging to the Geraniales, the Rosacese and the Ranunculaceae, 
compared with the vessels of Ephedra and Gnetarn. It is shown that 
Radial section of Ephedra- or Gnetum - like vessel 
perforation in Pelargonium sp. x 400. 
in the groups examined and in numerous other Angiosperms the vessels 
have typical scalariform perforations side by side with the bordered 
perforations regarded as characteristic of the Gnetales. There appears 
to be no foundation for recent statements that the vessels of the 
Gnetales and the Angiosperms have different and distinct modes of 
origin. S. G. 
