624 



BOTANY OF THE LIVING PLANT 



The general conditions of pollination are the same as in Caltha, but with 

 honey at the base of the coloured petals. 



Fig. 474- 



Buttercup [Ranunculus acris, L.). i, Flower in median section. 2, a single petal. 

 3, the gynoecium. 4, the same in section. 5, floral diagram. 



mm 



^m, 



Each carpel matures as a dry indehiscent nut, falling away with its single 

 seed within (Fig. 473, B). Comparing with Caltha the flower is more 

 elaborate and probably derived from the type of the Helleboreae, by con- 

 version of the outermost stamens first into honey- 

 leaves, as in Helleborus or the Globe-Flower, then 

 into large honey-bearing petals, as in the Buttercup 

 (compare Fig. 189, p. 264). The carpels meanwhile 

 had their ovules reduced to one each, while the pro- 

 pagative power was made up by increase in the 

 number of carpels. 



(17) The Monkshood (Aconitum Napellus, L.) is a 

 perennial with swollen storage roots, commonly grown 

 in gardens : it is an important drug. Its inflores- 

 cence is a raceme, developing as a cymose panicle 

 below. The flower shows median zygomorphy 

 (Fig. 475), and consists of : 



Calyx, sepals 5, polysepalous, inferior, corresponding 

 in number and position to the Buttercup, but petaloid ; the posterior sepal 

 enlarged as a hood. 



Corolla, petals usually 8, of which the two obliquely posterior are elongated 

 into stalked glandular spurs (nectaries), covered by the hooded sepal ; the 

 rest are small ; polypetalous, inferior. 



>«§gp> 



Fig. 475. 



Floral diagram of Aconi- 

 tum. (After Eichler.) 



