LIFE HISTORY OF A GYMNOSPERM 
27 
or wings, one on either side of the fertile cell. The purpose of the 
latter is to give greater buoyancy in the air to the microspore. 
Carpellate Cones.- — The young carpellate cones appear in May or 
early June as pinkish-purple structures arranged in solitary fashion 
or in small groups, lateral along the new growth. Each terminates 
Fig. 9. — Scotch pine ( Pinus sylvestris) . A-D, stages in the development of the 
carpellate cone, and its carpotropic movements. E, very young carpellate cone 
much enlarged; F, ventral, G, dorsal views of a scale from E; 1, ovuliferous scale; 
2, ovule (in longitudinal section); 3, pollen chamber and micropyle leading to 
the apex of the nucellus (megasporangium); 4, integument of the ovule; G, 1, tip 
of ovuliferous scale; 5, bract; 4, integument; H, longitudinal section at right 
angles to the surface of the ovuliferous scale (diagrammatic); 6, megaspore; 7, 
pollen chamber; I, longitudinal section of a mature cone; 6, ovule; J, scale from 
a mature cone; 6, seed; w, wing of seed; K, dissection of mature seed; h, hard seed 
coat; c, dry membraneous remains of the nucellus, here folded back to show the 
endosperm and embryo; e, embryo; p, remains of nucellus; L, embryo; c, cotyle- 
dons; e, hypocotyl; r, root-end. (Gager.) 
a lateral axillary branch. A carpellate cone is composed of a main 
axis which bears spirals of scales, by some termed megasporophylls 
{carpels). Each scale is composed of an ovuliferous scale bearing 
two ovules or megasori and a bract. Each megasorus contains a 
nucellus or megasporangium which is surrounded by an integument 
