CIIOIIISIS OH DEDUPLTCATION. 



245 



next within, the lateral and exterior petals ; those alternate and 

 within these, the inner circle of petals ; and alternate with these are 

 the anthers of the two stamen-clusters. The centre is occupied hy 

 a section of the pistil, which consists of two united. The three sta- 

 mens arc lightly connected in Dicentra (Fig. 371) ; hut in Corydalis 

 and Adlumia th'ire is only one strap-shaped filament on each side, 

 which is three-forked at the tip, each fork hearing an anther (Fig. 

 374). We have a .similar case in some Hypericums and in Elodea 

 (Fig. 375), except that, while the floral envelopes are in fives, the 

 circles within them are commonly in 

 threes. The three memhers of the 

 androccium are normally placed, alter- 

 nating with the three memhers of the 

 gynaicium within, and also with three 

 glands, which probably replace another 

 circle of stamens. Now each real 

 stamen is here multiplied into three, 



united below ; so that the whole compound body may be viewed as 

 homologous with a compound trifoliolate leaf (289). If this be so, 

 then each cluster of numerous stamens in the common St. Johns- 

 wort may be regarded as answering to one stamen greatly multiplied 

 in the same way, and as analogous to a sessile decompound leaf. 

 And the same maybe said of each stamen-cluster in the Linden 

 (Fig. 383). The actual development of the cluster, from a protu- 

 berance which in the forming flower-bud occupies the place of a 

 single stamen, has been traced by Duchatre, Payer, &c. in this and 

 other cases. 



457. Thus far Ave are sustained by a clear analogy in the organs 

 of vegetation. As the leaf frequently develops in the 

 form of a lobed, divided, or compound leaf, — that is, as 

 a cluster of partially or completely distinct organs from 

 a common base, — so may the stamen, or even the pistil, 

 become compound as it grows, and give rise to a clus- 

 ter, instead of completing its growth as a solitary organ : 

 and it appears that the organogeny is strikingly sim- 

 ilar in the two cases. Nor is it very unusual for petals to become 

 divided or deeply lobed in the same manner ; as, for example, those 



FIG 375. Diagram (cross-section) of a flower of Elodea Virginica. 376 One of the turea 

 Btamen-cl asters, consisting of a trebled stamen, enlarged. 

 1'IG. 377 A petal ol Mignoiu-tto. inlaiged. 

 21* 



