38 
T ho day . — Anatomy of the Ovule and Seed in 
Text-fig. i is the diagrammatic representation of the top part of 
a young ovule in which the changes have begun. The figure is built up 
from longitudinal sections connected with the series of transverse sections 
figured in Photos 1-6, PL I. 
From the opening in the thick fleshy outer covering (c) freely projects 
the open tip of the micropylar tube. The micropylar canal is still open 
throughout, though at two places it shows signs of narrowing. The wall of 
the micropylar tube is already growing in thickness, and at Af and Bf are 
seen projecting portions. Into Bf fits the tip of the middle covering. The 
details of this figure are better explained by reference to the photographs 
and descriptions of the transverse 
sections. 
In one of the smallest ovules 
examined by transverse sections, 
a section through the apex of the 
ovule shows, within the outer fleshy 
covering, the small withered micro- 
pylar tube, with its wall composed 
of four or five layers of cells, and 
a circular lumen with a thickly 
cuticularized lining. A little lower 
(see Photo I, PI. I), the cuticu- 
larization of the lining becomes 
less, and the cells of the outer 
epidermis become conspicuously 
larger, tending to project outwards 
to form small protuberances. A 
few sections lower there appears, 
between the outer covering and the 
micropylar tube, a thin ring of tissue one cell thick (/, Photo 2, PI. I). 
When this is traced downwards it is found to be an upward continuation of the 
papillate outer epidermis of the micropylar tube (p, Photo 2, PI. I). That 
is, it is formed by upwardly directed papillae, closely appressed laterally 
(Text-fig. i, Af). It is the beginning of the upper c flange’ described in an 
older ovule by Miss Berridge ; in her drawing of a longitudinal section 1 she 
figures rows of cells directed upwards , which must have had their origin as 
now described. In the region below these freely projecting hairs, the wall 
of the micropylar tube is about 6-7 cells thick, and though the outer 
epidermis is fringed with prominent papillate cells they have not projected 
far out into the cavity between the micropylar tube and the outer covering 
(Photo 3, PI. I). 
At the level of the upper flange, the lumen of the micropylar tube 
1 Berriclge, 1911 , p. 112. 
of young ovule of G. Gnemon , 3 mm. long, in which 
closure of micropyle is just beginning. C, outer 
covering ; o, middle covering ; I is the inner covering 
terminating in the freely projecting micropylar tube. 
Af Bf are the beginnings of the projecting upward 
and downward flanges of the micropylar tube. 1-6 
represent the levels of Photos 1-6, PL I. 
