264 Hill and de Fraine . — A Consideration of the 
Further, the impression derived by Miss Winifred Smith 1 from a study of 
sapotaceous seedlings was that , i while there is a characteristic type of ana- 
tomy for the order, it is subject to adaptive variations as to the number 
of strands, primary and otherwise.’ 
In cases where there is little or no doubt regarding the affinity of two 
plants or groups of plants, the seedling-structure may be correlated with the 
affinities determined on other characters, but in instances where the relation- 
ship is open to question, the details of seedling anatomy do not appear to 
help to any considerable degree, for the plants in question may have the same 
seedling-structure, which does not necessarily mean affinity, e. g. Anemar- 
rhena and Incarvillea , and Persoonia and Pinus i or the seedling structure 
may be quite different, which does not necessarily indicate remote affinity, 
e. g. Incarvillea Delayvei and Eccremocarpiis scaber (N. O. Bignoniaceae). In 
other words, it does not appear possible to assign a true value to the characters 
in question in cases where often they would prove of greatest worth. 
For these reasons we see no necessity for preserving seedling anatomy 
from the fate already meted out to other structural features, e. g. secondary 
thickening, which were at one time considered as indicators of phylogeny, 
a conclusion arrived at, either entirely or in part, by others who have paid 
attention to the facts of seedling anatomy . 2 In fact, until more knowledge 
is obtained with regard to the interrelationship of plant members and the 
influence of environment — in a word, the influence of physiological necessity 
on morphological expression — we cannot determine with any degree of 
certainty the precise value of many anatomical characters. 
Physiology. 
Of the factors which have a bearing on the structure of seedlings, the 
influence of the adult structure 3 and the importance of the size of the 
seedling have already been considered. There are, however, many more — 
too numerous to deal with here — of which we propose to consider questions 
relating to the size and number of the vascular bundles, for it is upon these 
that the transition phenomena depend. 
First, as regards the number of the cotyledonary bundles. The size 
of the seeds of Gymnosperms, and also Angiosperms, varies considerably, 
and depends to a great extent upon the amount of reserve food material. 
It is an important fact that when the amount of such reserve food is rela- 
tively large — and hypogeal seedlings are remarkably dependent on their 
cotyledonary food reserves for their early development, as contrasted with 
1 Smith, W. : The Anatomy of some Sapotaceous Seedlings. Trans. Linn. Soc. London, 
vol. vii, Bot., Pt. II, 1909. 
2 See Lee, loc. cit. ; and Compton, R. H. : An Investigation of the Seedling Structure in the 
Leguminosae. Journ. Linn. Soc., June, 1912, xli. 
3 Hill and de Fraine : Proteaceae, loc. cit. 
