4 8 



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 (micros porophylls 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, i, 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; /, 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 (micros porangia), 

 which develop the micros pores (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 



