408 BOTANICAL GAZETTE [MAY 
depends on nutrition, a poor food supply causing but slight enlargement of the 
part, whereas a good food supply causes considerable enlargement. The 
vegetative point, on the other hand, is unrelated to nutrition, so far as its 
symmetry is concerned. Contrary to most previous investigators, BOSHART 
finds no evidence that gravity or light influences leaf symmetry. It is believed 
rather that both anisophylly and leaf asymmetry are merely an expression of 
the symmetry of the plant as a whole. For example, anisophylly, and in most 
instances asymmetry also, is associated with dorsiventrality, radial shoots being 
characterized commonly by isophylly and symmetry. It seems very doubtful 
if this radical view, giving little or no place to the operation of external factors, 
will displace the many experimental contributions of past years. Even in this 
contribution it is admitted that good nutrition can result in the development 
of the vegetative point of a dorsiventral shoot into a radial shoot. It would 
seem, then, according to BosHart, that external factors determine what sort of 
a shoot develops, but that the type of leaf is tied up inexorably with a particular 
kind of shoot.—HENry C. CowLes. 
Photometric leaves and shoots.—WIEsNER in continuing his already 
very extensive studies upon the light relations of plants returns to the consider- 
ation of the orientation of leaves in response to the direction of incident light. 
Fixed and variable positions” are distinguished and examples of the latter, 
which he regards as the more perfect response, are multiplied, the legumes 
furnishing the major portion. More exact studies are made of leaves only 
apparently related to light and termed pseudophotometric,*3 in contrast to 
those actually orienting themselves in response to incident light, and emphasis 
is laid upon the part played by epinasty and geotropism acting before and 
simultaneously with phototropism. Most photometric — are found to be 
pseudophotometric in the earlier stages of their developme 
Relations similar to those existing in leaves are shown to a for shoots."4 
All shoots with photometric leaves are shown to be themselves photometric, 
but the category also includes the shoots of such conifers as Abies and Tsuga, 
ons leaves showing very slight responses to light. The effect of light of 
ent intensities is to be seen in the shoots of Taxus baccata, being per- 
ede that is showing euphotometry, while with more intense light they 
become panphotometric. Some interesting cases of the photometry of ani- 
sophyllous shoots are also discussed.—Gro. D. FULLER. 
” WiesNER, J. v., Uber fixe und variable Lichtlage der Blatter. Ber. Deutsch. 
Bot. Gesells. 29: 304-307. 1911. 
33 WIESNER, J. v., Uber aphotometrische, photometrische, und pseudophoto- 
metrische Blatter. Ber. Deutsch. Bot. Gesells. 29:355-361. 1911. 
%4 WiESNER, J. v., Uber die Photometrie von Laubsprossen und Laubsprossys- 
temen. Flora 105:127-143. 1913. 
