STRUCTURE OF FLOWERS. 117 



Malpighiaceae. The stamens also frequently bear nec- 

 tariferous glands, particularly on the anthers or connec- 

 tivum, as in Adenanthera, Prosopis, &c. 



In all these examples the symmetry of the flower is 

 not in the least altered, because the nectaries are placed 

 regularly ; but it very frequently happens, that we find 

 in irregular flowers the nectaries so placed as to have no 

 connexion with the symmetry. Is it the presence of 

 these irregularly placed nectaries which causes the irre- 

 gularity of the flower, or is it the irregularity of the 

 flower which causes that of the nectaries ? It is pro- 

 bable that these two causes are each true in certain 

 cases, but we can only observe the concordance of the 

 facts without determining which is the cause of the 

 other. Thus, in a great number of irregular gamope- 

 talous corollas, such as the Labiatae and Scrophula- 

 rinege, we find upon the torus a nectariferous gland, 

 placed upon one side of the ovary, but wanting on the 

 other. 



It frequently happens that when one sexual organ is 

 abortive, its place is occupied by a nectariferous gland. 

 Thus, in the Scrophularineas, the place of the abortive 

 stamen is often occupied by a gland ; in several mo- 

 noecious or dioecious plants the pistil is replaced in the 

 male flowers by a nectariferous gland. 



The nectaries upon the inner surface of the corolla 

 are always superficial, and they often cause a cavity 

 there, which, seen from the exterior, forms a kind of 

 knob or spur. It is in this sense that Sprengel has given 

 these organs the name Nectarotheca ; thus, the base 

 of the spur of Linaria, the violet, &c, always presents 

 a nectary more or less developed ; and when these 

 flowers become regular, each of their spurs contains a 

 nectary. 



The genus Parnassia has very remarkable nectaries. 



