396 BOTANICAL GAZETTE [NOVEMBER 
average height, with shorter heads and fewer grains, thus emphasizing the 
importance of selecting the superior plants instead of the superior individual 
grains. As this variety of oats was undoubtedly a mixture of several distinct 
biotypes, it does not follow that the same mathematical results would be 
found in other varieties composed of different mixtures. The variety with 
which WALDRON worked may have contained a short-headed, short-culmed, 
heavy-grained biotype. In some other mixture the heavy-grained biotype 
might have longer culms, longer heads, and more numerous grains, and it 
would then give a positive correlation where WALDRON found a negative 
correlation, but this does not lessen the importance of the conclusion reached 
that the individual plant and not the individual grain is the proper unit of 
selection.—Gero. H. SHULL. 
Anatomy of the seedling of Trapa.—A short paper by Queva‘: on the 
curious seedling of Trapa natans recalls the case of “‘caulicle” vs. ‘‘radicle,” 
the question of the importance of the root as a primarily essential part of a 
seed plant. The author confirms the observations of previous investigators 
concerning the marked inequality of the cotyledons, the negative geotropism 
of the caulicle (which he prefers to call the hypocotyledonary axis), and the 
presence of internal phoem in the stem and leaves. His own investigation 
has resulted in the discovery of this internal phloem in the hypocotyledonary 
axis and in the petiole of the cotyledon. Although he finds in the very tip 
of the hypocotyledonary axis a vascular condition which is peculiarly root- 
like (two xylem points alternating with two small groups of phloem), yet he . 
thinks it is not root, because (1) there is no rotation of the strands in succes- 
sive levels from the tip of the organ to the cotyledonary node; (2) the xylem 
points are too near the periphery of the cylinder to look like root poles; and 
(3) the whole organ is covered by epidermis, except at the spot where the 
suspensor was attached. The growth of the caulicle, or hypocotyledonary 
axis, is limited; the roots strike out from its side, their vascular strands being 
inserted on certain metaxylem elements discernible in cross-section on one 
side of the vascular cylinder —Sister HELEN ANGELA 
Sporophylls of Selaginella——Syxes and St1tes*? have made a very inter- 
esting study of the sporophylls of Selaginella, finding an amount of variation 
and a degree of complexity that have not attracted attention heretofore. 
A few of the more representative especies are described and the different 
forms of the sporophyll are pointed out as “special adaptations for the secure 
protection of the sporangia.” In many sporophylls there is a well developed 
air cavity in the base, and the authors suggest “that they recall the mucilage 
™ QuEva, C., Observations anatomiques sur le Trapa natans L. Compt. Rend. 
Assoc. Fran. Av. Sei. 1909. Con ngrés de Lille, pp. 512-517. figs. 2. 1909. 
«2 Sykes, M. G., and Srixs, W., The cone of the genus Selaginella. Annals of 
Botany 24: pee pl. 41. 1910. 
