368 



XXVII. REPRODUCTION OF GYMNOSPERMS. 



leaves, which succeed the flowers in uninterrupted series. The 

 flowers also, like the short shoots, stand in the axils of scale- 

 leaves or bracts. Upon the stalk of the male flowers, we find 

 first three decussating pairs of bracts. The lowermost pair is 

 placed laterally with regard to the primary bract and the parent 

 axis, an arrangement which is due to the necessities of space, and 

 which is almost always found in the first pair of leaves of the 

 vegetative buds of Gymnosperms. To the bracts of the short 

 flower-stalk succeed the stamens, closely crowded, usually ar- 



FIG. 134. Pinus Pumilio, resembling P. sytoestris. D, from P. sylvestris. A, 

 longitudinal section through a nearly ripe male flower (x 10). , longitudinal section 

 through a single staminal leaf (x 20). C, cross-section through a staminal leaf 

 (x 27). />, a ripe pollen-grain ( x 400). 



ranged in ten vertical rows. The floral axis is elongated, fusiform. 

 A single stamen separated and examined under the simple micro- 

 scope shows its under side occupied by two longitudinally-inserted 

 pollen-sacs, meeting one another in the middle line ; its tip 

 is extended into a short, upturned edge. 



Median longitudinal sections through the flower, shortly before 

 the dehiscence of the anthers (Fig. 134, A), show, especially after 

 treatment with potash, the course of the vascular bundles in the 

 floral axis, the series of staminal leaves, each with a single 



