308 BOTANICAL GAZETTE [NovEmBER 
CocKAYNE5? has found that Discaria Toumatou, a New Zealand xerophytic 
shrub that normally has long pungent spines, fails to develop these spines in 
moist chamber cultures. It is believed that the juvenile leafy shoots instead 
of spines would continue indefinitely in such conditions. He regards these 
facts as highly favorable to the xerophytic rather than the protective theory of 
thorns.—H. C. CowLes. 
HARSHBERGER®. proposes that the term zone in plant geography be restricted 
to broad belts determined by latitude, conforming to the law of priority as we 
as dominant usage. Mountain zones he would term belts; concentric pond 
zones, circumareas; submerged shore zones, shelves; strand, river, or prairie edge, 
strips; island zones, girdles; and vertical forest zones, layers.—H. C. CowLes. 
HARSHBERGER has been making further floristic studies on the North American 
flora. One paper®t deals with the comparative age of the various elements in 
eastern North America, and there is a chart that shows the supposed relative 
time of appearance of these elements from the Miocene until now. A second 
paper®? deals briefly with centers of dispersal—H. C. CowLes. 
SWELLENGREBEL®S finds something to attract him in the dunes of the Nether- 
lands in spite of H. Brrvx’s assertion that they have no true dune plants, and 
that if present they would be of no interest! The plant societies noted are those 
of the sea dunes, the gray dunes, and the dune hollows. Detailed notes are 
given concerning the source of the dune flora~—H. C. CowLes. 
IN A LECTURE before a convention of practical farmers at Breslau, January, 
1905, T'SCHERMAK®4 gave a clear exposition of the recently discovered laws of 
inheritance and their significance for practical agriculture. He also included a 
brief discussion of variation and mutation.—G. H. SHULL. 
A coop accounts of the Desert Botanical Laboratory and of the more 
striking vegetation in its vicinity has been published by Professor LLOYD. —H. C. 
Cowles. 
59 Cockayne, L., On the significance of spines in Discaria Toumatou Raoul 
Giana). New Phytol. 4:79-85. 1905. 
6° HARSHBERGER, J. W., Suggestions toward a phytogeographic 
Science N. S. 21:789-790. 1905. 
6: HARSHBERGER, J. W., The comparative age of the different fl 
of eastern North America. Proc. Acad. Nat. Sci. Phil. 1904:601-615- 
se , Original centers concerned in North American. plant dispe 
1905: 2. 
3 SWELLENGREBEL, N., Ueber niederlindische Diinenpflanzen- 
Centralbl. 187: 181-198. 1 3 
64 TSCHERMAK, E., Die Sees Vererbungsgesetze un ee Landw. 
Anwendung fiir die rationelle Pflanzenziichtung. Reprint from Wien 
Zeitg. nos. 17, 18, 19. pp. 31. 1905. 66: 
6s Lioyp, F. E., A botanical laboratory in the desert. Pop. Sci. Monthly 
329-342. 1905. 
nomenclature: 
oristic elements 
rsal. Ibid" 
