the Inflorescences and Flowers of Ephedra . 967 
forming a little cap as in Gnetuni} For some little distance above the level 
at which the nucellus becomes free from the inner integument, the cells com- 
posing its epidermal layer are drawn out into papilla-like outgrowths (Text- 
fig. x). 2 At its base the nucellus is separated from the small-celled tissue 
belonging to the region of the inner integument by a thin layer of crushed 
cells, empty of contents, with suberized walls, which forms a cup, internal to the 
larger cup formed by the vascular bundles and their transfusion tracheides, 
extending upwards to about the same level, and separated from it by two or 
three layers of parenchyma (Text-figs. V, C, and XI. 3, c). It is very difficult 
to imagine what may be the function of such a cup of suberized cells. 
Text-fig. xn. 1-3. E.altissima. Diagrams of transverse sections through ovule ; i = through 
apex of micropylar tube; 2 = through the outer integument at the level of the lower part of 
micropylar tube ; and 3 = at a level about half-way up the ovule. Letters as before. 
E. aliissima. The single ovule of E. altissima differs to some extent 
from the ovule of the bisporangiate E. distachya. The great difference in 
size may be seen by a comparison of Figs. 2 and 3 a y PI. LXXXV, which are 
magnified to the same scale. It is of course no longer laterally compressed 
by the presence of another ovule, though it is still angled, its angles being 
1 Thoday (Sykes), 1911, pp. 11 13-14. 
2 Pearson has suggested that during the disorganization .of the nucellar apex in Welwitschia 
a good deal of the mucilage afterwards found in the micropylar tube is formed, and he also produces 
evidence to show that some of this mucilage is secreted by the outer layers of the nucellar cone 
(1909, p. 343). It appears probable that in Ephedra also, while some of the mucilage originates 
by disorganization to form the pollen-chamber, some of it is similarly secreted by the papillate cells 
of the nucellar epidermis, 
