454 SPERMATOPHYTES (SEED PLANTS) 
gether, but they do not form close clusters as the staminate 
cones do. 
The scales of the ovulate cones are considered too complex to 
be called sporophylls, for each scale consists of an ovuliferous 
scale (ovule-bearing scale) and a bract, the two being partly united. 
Some morphologists think that the ovuliferous scale itself repre- 
sents two sporophylls fused together. The megasporangia or 
= 
—— 
= 
2S 
Ss 
= 
Ss 
SS 
SS 
SASS 
Sore 
as 
=> 
PEE 
ere 
Fic. 403. — The ovulate structures of the Pine. A, branch bearing four 
ovulate strobili, B, ovulate strobilus, showing the arrangement of scales 
(X about 2); C, a view of the inner or upper side of a scale, showing the two 
sporangia (s). 
ovules, two in number, are borne on the upper side and at the 
base of the ovuliferous scale (Fig. 403). The scales are spirally 
arranged and closely crowded, but during pollination they spread 
apart, and the pollen can slide in between them and reach the 
ovules. After pollination the scales close together again, and the 
cone is made water-tight by a secretion of resin. After pollina- 
tion the cone also changes from the vertical to the nodding 
position. 
The ovules consist of an integument and a nucellus, and deeply 
buried within the nucellus the four megaspores occur. The 
ovules are arranged one on each side of the median line of the 
scale, with the micropyles pointing downward. The integument 
