48 
PHARMACEUTICAL BOTANY 
Staminate Cones. —The yellow, ovate, staminate cones appear 
about May and are clustered at the base of the new growth of the 
current season. Each consists of a main axis (modified branch) 
which bears spirals of scales (microsporophylls or stamens). On the 
Pig. 22.—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; i, 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.) 
under surface of each scale are the spore-cases (microsporangia ), 
which develop the microspores (pollen grains). Each pollen grain 
when mature consists of a central fertile cell and a pair of air-sacs 
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 
