APPENDIX A 



623 



Fig. 472. 



composition of the perianth : also by the fact that all the parts are inserted 

 separately upon a conical receptacle. It includes herbs or shrubs of 

 temperate and cold climates, with alternate 

 ex-stipulate leaves, having palmate venation. 

 They are mostly acrid, and poisonous. 



(15) A simple type of their floral construction 

 is seen in the Marsh-Marigold {Caltha palustris, 

 L.), common in wet places. It is a coarse herb, 

 with creeping rootstocks and cordate radical 

 leaves. The flowering stems are sub-erect, with 

 a few leafy bracts and cymose branching. The 

 large yellow flowers consist of : 



Perianth, a single series of petaloid sepals, 

 5 or more, imbricate in bud : the outermost 

 obliquely anterior ; polyphyllous, and inferior. 



Androecium, stamens indefinite (80 to 150), 

 free, hypogynous, dehiscent by lateral slits. 



Gynoecium, carpels 5 to 10, apocarpous, 

 superior. They are follicles, with margins 

 turned centrally, to which the numerous 



ovules are attached in two rows (Fig. 472). Pistil of Caltha, with numerous apo- 

 Each has a terminal stigma, while near the carpous carpels. Enlarged. 



base of each, on either side, is a group of honey-secreting hairs. Ovule 



anatropous. 



The pollination is not highly specialised ; the symmetry is radial ; the 



attractions are colour, and honey on the carpels ; there is slight protandry 



and the stamens mature in succession, 

 so that the supply of pollen is prolonged. 

 There is a probability of intercrossing, 

 but self-pollination is possible. 



The fruit is a group of follicles, which 

 open by their ventral sutures, and gap- 

 ing widely upwards allow their seeds to 

 escape (Fig. 473, A). 



(16) The Buttercup {Ranunculus 

 acris, L., or other species) is more 

 specialised, having both calyx and 

 corolla; but the flower is constructed on 

 a similar plan ; as follows : (Fig. 474.) 

 Calyx, sepals 5, polysepalous, inferior, 

 imbricate in bud, the outermost being 

 obliquely anterior. 



Fig. 473. 

 A, Follicles of Aconite. (After Figuier.) 



B, Achene or nut of Buttercup. (After Figuier.) 



Corolla, petals 5, polypetalous, alternating with the sepals, inferior yellow, 

 with a honey-pouch on the upper face of each, near the base (Fig. 474, 2). 



Androecium, stamens indefinite, free, hypogynous ; the outermost maturing 

 earliest. 



Gynoecium, carpels indefinite, apocarpous, superior : each contains only a 

 single anatropous ovule ; otherwise similar in form to the fewer and larger 

 carpels of Caltha. 



B.B. 2 R 



