MORPHOLOGY OF EEPRODUCTIVE ORGANS 145 



spring from it at a little distance from the thalamus. The 

 corolla and stamens are then said to he perigynous {figs. 271 

 and 272). The cup of the calyx bearing the stamens and petals 

 may surround and closely embrace the ovary, when the latter is 

 said to be inferior, and the corolla and stamens are epigynous 

 ( fig. 273) . Though such a pistil appears to bear the other whorls 

 upon its apex, this is not really the case ; it is always the terminal 

 whorl. 



Another interpretation of the structure of the inferior ovary 

 is possible in many oases. It may arise from the early sup- 

 pression of the apical growth of the thalamus and the continua- 

 tion of the development of its peripheral tissue, which thus rises 

 as an annular zone or ciip. On the margin of this cup are 

 developed successively the perianth, stamens, and carpels. The 

 latter close in above the cup and cover over its cavity, extending 

 some distance downwards internally. The outer wall of the 

 ovary is so formed not of the calyx tube, but of the hoUowed-out 

 thalamus or receptacle. This view of its origin is supported by 

 the fact that in some cases the ovary of the Gooseberry is found 

 to have one or two small foliage leaves springing from it, indi- 

 cating the axial nature of the outer wall. 



Adhesion between the stamens and petals is very common. 

 It is generally associated with cohesion in the corolla, and is 

 accounted for by the outgrowth from the re- 

 ceptacle of an annular zone from which spring ' " ' 

 both petals and stamens. These arise from it 

 by apical growth at first, but this is soon 

 replaced by basal as before described, and the 

 whole of the bases of the two whorls are so 

 developed as a single band of tissue. The 

 origin is thus comparable to the fusion of all 

 the perianth leaves in the Lily-of-the-valley 

 abeady described. Such an arrangement of ''t!i^s^^lf,^!^is 

 stamens is called epipetalous {fig. 274). canadensis). 



7. Spiral Phyllotaxis. — In the Gymno- 

 sperms both male and female flowers have frequently this form of 

 phyllotaxis. Good instances are afforded by the so-called cones of 

 many genera, which were formerly regarded as inflorescences. 

 These structures constitute the female flowers of such forms 

 as Pinus, Abies, &c. {fig. 275). Each consists of a woody axis 

 on which the sporophylls are arranged in a close spiral. 

 Each sporophyll is at first succulent, but ultimately becomes 

 hard and woody. It bears on its upper surface a large scale-like 

 VOL. I. L 



