170 EVOLUTION OF PLANTS 
pollen-spores produced is enormously in excess of the 
macrospores. Indeed, so abundant is the pollen, that 
the ground in the neighborhood of the trees is some- 
Fig. 42 (Conifere).— A, branch of a pine (Pinus contorta) with male 
flowers, fl; B, longitudinal section of a single flower, showing the 
arrangement of the sporophylls; C, a single sporophyll, showing the 
two microsporangia, mi, upon its lower surface; D, a section through 
the microsporangium ; E, a single microspore, showing the antheridium, 
an, and the vesicular outgrowths of the wall, v, which serve as sails; 
F, a female flower of the same pine; G, a single sporophyll from the 
female flower, showing the small scale, sc, by which it is subtended; H, 
a sporophyll from an older cone, showing two macrosporangia (ovules), 
ma, upon its inner face; I, longitudinal section of an ovule (macro- 
sporangium); the large macrospore contains the gametophyte, g, 
bearing several archegonia, ar; p, a pollen-spore sending down the tube 
by which the meoherouls are fertilized; J, a young embryo; sus, sus- 
pensor; x, apical cell; K, section of a ripe seed, containing the embryo, 
em, imbedded in the prothallial tissue, g; L, young sporophyte, show- 
ing the cotyledons, cot; stem, 8¢; root, r; s, the empty seed-coat. 
times covered with a layer of the sulphur-colored 
powder. 
The germination of the pollen-spores and the fertili- 
zation of the archegonium are effected as in Taxus. As 
in that genus, no trace of motile spermatozoids has yet 
