306 



THE STRUCTUEE OF FLOWERS. 



homologous with one leaf alone ; but the membranes belong- 

 ing to each anther, being of, at least, two layers of cells, 

 have become foliaceous, just as the epidermis of the nucellus 

 has done in the cases herein described; so that, in the 



Jatroplia, two leafy expansions were 

 developed out of one. 



Other instances are known of ovules 

 being represented by leaves, as Primula 

 Sinensis, Symphytum officinale,* and 

 Sisymhrium Alliaria (Fig. 86). 



Theoretically, it might be objected 

 that a leaf (carpel) should give rise to 

 a leaf (ovule or, at least, ovular coat) ; 

 but foliaceous excrescences from a leaf- 

 Fig. se.-Metamorphosed ovules surface are not at all uncommon, as, 

 ^^H ^Srt^m'S: for example, frequently occur in Cab- 

 ncea, xvii.. t. 20). bages,t where, in consequence of high 



nourishment inducing hypertrophy, any " rib " or " vein " 

 may throw off a branch which can form a leafy expansion, 

 which not at all infrequently becomes 

 funnel-shaped, like the abortive ovules of 

 the Mignonette. Similar funnel-shaped or 

 tubular productions are found on corollas 

 of semi-double flowers, as in Primulas, 

 Cyclamens, Antirrliinum, etc., sometimes 

 externally. Fig. 87 represents a like out- 

 th'e7abeUumTf growth from the labellum of Cattleya 

 Mossiece; and I have seen the posterior 

 sepal of Vanda ccerulea replaced by a pedicel with a cup at 

 the apex exactly like the terminal process in Fig. 85, a. In 

 all these cases I would regard such productions as due to 

 hypertrophy. 



* Teratology, p. 263. t I^id., p. 312, fig. 166. 



Fig. 87. — Tubular excres- 

 cence on " 

 Cattleya MossieoB. 



