1903 | CURRENT LITERATURE 149 
KARL RUDOLPH has investigated the development of the spines of Opun- 
tia missourtensis’? and finds them purely epidermal and axillary outgrowths, 
not at all homologous with leaves or branches.—C. R. B 
Lutz, after experimenting with certain fungi, suggests ® that alkaloids in 
plants may be utilizable as plastic material when there is present an adequate 
supply of nitrates. So also a plant needs carbohydrates in excess before it 
can utilize asparagin. Lutz directs attention to the fact that certain plants 
(e. g., aconite and belladonna) are rich in alkaloids when they grow in poor 
soil, but poor in alkaloids when cultivated in gardens, or when found in a soil 
rich in nitrates.— C. R 
MEssrs. SEWARD AND ARBER have critically examined a number of palm 
seeds from the Lower Tertiary of Belgium, England, France, and Italy.° 
The conclusion is reached, that they all belong to a single extinct species, 
Nipadites Burtini Brong. It is interesting, that at the present time a mono- 
typic genus, Vifa friuticans, prevails in the Sunderbunds and in other south- 
ern Asiatic and Malayan deltas. The authors are of the opinion that the 
presence of Nipadites Burtini, together with other tropical forms of vegeta- 
tion, in the early Tertiary beds of Europe make it extremely probable that a 
very much warmer climate prevailed at that epoch, than is now found in the 
same mapas C, JEFFREY. 
BENECKE, in an investigation of the formation of oxalic acid in green 
veo finds that maize plants form oxalates or not according as he supplies 
bases for combining with the oxalic acid. If nitrates be supplied, oxalate is 
produced; if ammonia salts (e. g., Sulfate) be used, no oxalate is formed. In 
other plants (Oplismenus, Fagopyrum, Tradescantia) he only succeeded in 
modifying the amount of oxalate by the culture conditions. The formation 
of raphides by Tradescantia was independent of external influences and could 
only be affected by the supply of calcium. In algae (Vaucheria, Spirogyra) 
no such relation could be determined. A useful summary of physiological 
literature of oxalic acid is given.—C. R. B 
HABITUAL POLYEMBRYONY in Euphorbia dulcis Jacq. (purpurata Thuill.) 
was described in a preliminary announcement” about a year ago. The full 
paper, ” with figures, confirms the previous observations. The more extended 
OLPH, KARL, ga zur Kenntniss der Stachelbildung bei Cactaceen. 
Oesterr. Bot. Zeits. 53: 105-109. fl. 7. 1903. 
Lutz, L., Sur le réle Pas sissies envisagés comme source d’azote pour les 
végétaux. "Bull. B Bot. Soc. France 50: 118-128. 1903. 
9SEWARD, A. C., and ARBER, E. A. N., Les eer des couches Eocénes de 
la Heise, Mem. Musée Roy. d’Hist. Nat. Belgique 2:—. 1902. 
 BENECKE, WILHELM, Ueber Oxalsdurebildung in griinen Pflanzen. Bot. Zeit. 
61°: 79-110. 1903. 
™*See Bor. Gaz. * oa 1902. 
AIER, F., Zur Kenntniss der Polyembryonie von ra na duicis Jacq. 
( purpurata Thuill.). ie Deutsch. Bot. Gesell. 21 : 6-19. f/. 
