352 



SEEDS 



is present in sufficient quantity to render the kernels of some 

 species of Pines of nutritive value. The method of germination 

 of the seeds is practically the same as that of a Castor Oil, the 

 seedlings (Fig. 195) possessing long hypocotyls (h.) with epigeal 

 cotyledons (cot.). 



During the development of the embryo the entire ovule 

 enlarges considerably, and at the same time the integument hardens 

 to form the seed-coat, or testa (s.). The greater part of the 



FIG. 205. Seeds and cones of various Conifers. A, longitudinal section 

 of ripe seed of the Stone Pine (Pinus pinea), showing the testa (s), 

 the perisperm (n, cf . p. 371) , endosperm (e) , and the embryo with radicle 

 (r) and numerous cotyledons (Co) ; B, young female cone of Juniper 

 (Juniperus) and C, ripe cone of same ; D, outer edge of ripe cone- 

 scale of Wellingtonia (Sequoia) ; E, single cone-scale of Pinus bearing 

 the two seeds with wings (w) ; F, ripe cone-scales of Douglas Fir 

 (Pseudotsuga) . b.s., bract scale; 0.5., ovuliferous scale. (B, after 

 Antoine.) 



latter comes to consist of very thick-walled tissue, foreshadowed 

 as a dark zone in the integument of a young Pinus-ovule 

 (Fig. 203, A, s.), and constituting the hard layer which is so 

 conspicuous a feature in the seed of the Stone Pine (Pinus pinea). 

 The micropyle appears on the testa as a minute opening, and 

 it will be realised, from the foregoing description, that the tip 

 of the radicle lies just beneath this. In Pinus and some of its 

 allies, a thin membranous flake becomes detached from the 



