APPENDIX A 



511 



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

 honey at the base of the coloured petals. 



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

 seed within (Fig. 415,5). Comparing with Caltha the flower is more elaborate 

 and probably derived from the type of the Helleboreae, by conversion 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. 1 80, p. 230). The carpels meanwhile had their 

 ovules reduced to one each, while the propagative 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. 417), 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 ; polypelalous, 

 inferior. 



Androecium, stamens indefinite, spirally arranged, free, hypogynous. 



Gynoecium, carpels usually 3, apocarpous, superior. Follicles and their 

 dehiscence as in Caltha. 



Comparing this flower with Ranunculus or Helleborus, it is clearly a zygo- 

 morphic development of the same type. The flower is protandrous. The 

 sepals give colour-attraction, and the honey is conveniently placed for humble- 

 bees in the posterior, spurred petals, while the whole is sheltered by the hood. 

 The protandry makes cross-pollination highly probable from successive visits. 

 After shedding their pollen the filaments curve back so as to expose the 

 receptive stigmas. Self-pollination is thus improbable. 



FIG. 417. 



Floral diagram of Aconi- 

 tum. (After Eichler.) 



ORDER: RHOEADALES. 

 Family: PAPAVERACEAE. Example: THE RED POPPY. 



(18) The Common Corn Field Poppy (Papaver rhaeas, L.) is an annual 

 which ripens its seeds before the corn is cut, and it is thus ready to spring 

 again in the next season. The plant, which is bristly and contains a milky 

 juice, consists of a leafy stem branched below. The solitary flowers are 

 terminal on their long hispid stalks, the buds hanging down, but the stalks 

 straighten before flowering, and in fruit (Fig. 418). The flower consists of : 



Calyx, sepals 2, polysepalous, inferior, antero-posterior, falling off at the 

 opening of the bud. 



Corolla, petals 4, polypetalous, inferior, wrinkled in bud, two lateral, two 

 antero-posterior. 



Androecium , stamens indefinite, free, hypogynous. 



