1916] CURRENT LITERATURE : 85 
conditions result in so vigorous a development of the flowers that the enveloping 
scales are burst.—J. M 
Morphology of Gnetum.—Prarson® has contributed much to our knowl- 
edge of Gnetum, a genus so suggestive of a relationship to angiosperms as 
to deserve the most critical study. The present paper is a well organized 
summary of the known facts in reference to the genus, and while the argument 
for angiosperm affinity is not convincing, it shows that the case is still open. 
PEARSON sees in the behavior of the fusing nuclei of Welwitschia and Gnetum 
too much suggestion of the behavior of the pois nuclei in angiosperms to be 
passed over lightly. As the author remarks, “while the whole question is 
involved in much obscurity, it is surely not desirable at the present stage of 
inquiry that the search for a primitive type at = ndosperm, from which that of 
the mngiocpernt may be edaenes owe cease.’ a from. the cde 
discussion, the paper facts and 
strobilus or ‘‘spike”’ of Onstens3 in a most suggestive way.—J. M. C. 
Temperature of leaves in winter.—Using careful methods of eae 
differences of temperature by an electrical apparatus, EHLERS,” working 
Ann Arbor, Michigan, upon Pinus Laricio, found that the. leaves through c 
absorption of radiant energy maintain during the winter temperatures of 2— 
to’ C. higher than the surrounding air. For the month of February, 650 
readings taken between the hours of 8:00 A.M. and 3:00 P.M., under all kinds 
of weather conditions, including both cloudy and bright days, gave an average 
differential temperature of 3206 C. Increased photosynthetic activity result- 
ing from such increases in temperature would seem to be of considerable impor- 
tance, and would tend to explain the presence and accumulation of the reserve 
food material found in evergreen leaves in winter by various workers. EHLE 
was unable, however, to obtain any conclusive evidence of cogiteayssteg eae 
tion during the months of January and February.—Gero. D. Futter. 
Structure of Alaria—In a recent publication of the Puget Sound Marine 
Station, Miss Krspr* describes the structure of Alaria fistulosa. In many 
features she finds a close resemblance to other Laminariaceae. The chief 
purpose of the paper is to trace at development = -~ cabolaes or —— 
character of the midrib. §$ ntinued 
transverse and radial division of cortical cells after the cells of ot ecabtia 
*8 Pearson, H. H. W., Notes on the morphology of certain structures concerned 
in reproduction in the genus Gnetum. Trans. Linn. Soc. London 8:311-332. Al. 
3I, 32. Igt5. 
*? EHLERS, J. H., The temperature of leaves of Pinus in winter. Amer. Jour. 
Bot. 2:32-70. 191 
* Kippe, Arice L., Some points in the structure of Alaria fistulosa. Puget 
Sound Marine Sta. Publ. 1: 43-57. pls. 8, 9. 1915. 
