On the Seedling Structure of Acer Pseudoplatanus. 
BY 
II. S. HOLDEN, D.Sc., F.L.S., 
AND 
DOROTHY BEXON, M.Sc., 
University College , Nottingham. 
With seventy-four Figures in the Text. 
Introduction. 
T HE morphology of the later stages in the development of the embryo 
of the sycamore and the germination of the seed were worked out by 
Lubbock ( 11 ) and described in his classic memoir ‘On Seedlings’ in 1892, 
and since then it has frequently figured in elementary text-books as an 
example of epigeal germination. A further description, again morphological, 
of the polycotylous seedlings so frequently occurring in this plant is given by 
Thiselton-Dyer ( 15 ), whilst Tansley and Thomas ( 14 ) make a brief reference 
to its anatomy in a short abstract dealing with their work on the vascular 
structure of seedlings. A more detailed knowledge of the early anatomy of 
the normal seedling was a necessary preliminary to projected work on poly¬ 
cotylous and syncotylous specimens, and the present paper is primarily the 
outcome of that need. 
The Food Reserves in the Embryo and Young Seedling. 
The embryonic food reserves comprise at least four substances. The 
first of these, starch , is distributed through the whole of the general paren¬ 
chyma of the embryo and rapidly disappears as growth proceeds, until, apart 
from that located in the starch sheath of the hypocotyl, it is absent by the 
time that the cotyledons are expanded. It has been recently shown by 
Briggs ( 2 ) that the sycamore seedling belongs to a type in which assimilates 
are produced immediately on exposure to light, so that these must be 
[Annals of Botany, Vol. XXXVII. No. CXLVIII, October, 1923.] 
