344 BOTANICAL GAZETTE [OCTOBER 
projecting stem tip and a meristematic region that later develops such a tip 
are of the same ontogenetic significance, and therefore that a cotyledonary 
ring may be lateral even if the stem tip is not organized. The cells that are 
to organize it later are still apical. It certainly also gives a aS and more 
consistent interpretation of the grass embryo than to imagine a cotyledon 
consisting of such distinct structures as scutellum, — and coleoptile, 
distinct in origin as well as in position and appearance. The author disposes of 
the dicotyledonous embryo of Agapanthus as meaning a RRR: char- 
acter, from which we are to infer that he still maintains the view that the dicoty- 
ledons have been derived from the monocotyledons. We had assumed that 
this view was no longer under discussion.—J. M. C 
Temperature and viability—WAcGONER™ finds that the resistance of 
radish seeds to high temperature is inversely proportional to the initial water 
content at the time of heating. At effective temperatures the water content 
fell with duration of heating. Three different varieties studied showed similar 
resistance. WAGGONER finds that much of the past work on resistance of 
seeds to high temperatures lacks precision because the operators allowed the 
water content to vary greatly during heating. They heated in water in open 
dishes, in the oven, or in dry corked flasks. The water absorbed or given off 
by radish seeds during heating as determined by the use of one or the other of 
these methods goes far to determine their resistance to heat. GRroves*® has 
taken care of this source of error by securing his seeds gas-tight in tubes just 
large enough to hold the roo seeds, thus leading to a rapid rise of vapor pres- 
sure with heating and an equilibrium between the vapor of the air and the 
water content without measurable water loss. It is interesting to see that 
radish seeds can be dried down to 0.4 per cent moisture without injury, for 
EwartT® has concluded that the sorts of seeds that are most resistant to drying 
cannot withstand a moisture reduction below 2 or 3 per cent without injury; 
while seat —_ and Populus will not withstand any drying in a desiccator.— 
Wm. Cro 
Organic nutrition of plants.—KNupson” has investigated the influence of 
certain mono- and disaccharides, added to nutrient media, on the growth of 
various green plants, as corn, peas, radish, vetch, etc. These plants can absorb 
through the root system and utilize sugars in growth. The order of the sugars 
with reference to beneficial effects varied with the kind of plant. Thus with 
corn grown in the light, the order was glucose and fructose, saccharose, maltose; 
Wacconer, H. D., The viability of radish seeds (Raphanus sativus L.) as effected 
by high temperatures and water. Amer. Jour. Bot. 4:299-313. fig. I- 1917- 
*s Bor. Gaz. 58:169-189. 1917. 
% Ewart, Proceedings and Trans. of the Liverpool Biol. Soc. 10:185-193- 1896. 
*1 Knupson, Lewis, Influence of certain carbohydrates on green plants. Cornell 
Agric. Exp. Sta. Mem. 9:1-75. 1916. 
