576 



BOTANY 



Family Aselepiadaeeae. — Corolla with contorted estivation ; 

 androecium haplostemonous ; pollen - grains of each loculus of the 

 anthers adhering together, in the form of a 

 pollinium ; carpels with free ovaries, 

 united above into a prismatic stigma. Plants 

 with latex (Figs. 559, 560). 



In their vegetative portions and fruit the Aselepia- 

 daeeae are like the Apocynaeeae, but differ from 

 them, as from all other Dicotyledons in the struc- 

 ture of their androecia. The stamens are united, at 

 least at the base ; each of them bears a large dorsal 

 appendage (Fig. 559, A). These staminal append- 

 ages together form a corona. Especially charac- 

 teristic, also, are the club-shaped pollen-masses or 

 pollinia, resembling those of the Orehidaceae [cf. 

 p. 488). For the purpose of pollination by insects, 

 the pollinia are attached in pairs (one pollinium 

 from each pair of contiguous anthers) to a corpus- 

 cultjM or glandular outgrowth of the stigma (Fig. 

 559, B, 0). 



Geographical Distribution. — The Aselepia- 

 daeeae are chiefly native of the Tropics, where they 

 are found as lianes or epiphytes. In the barren 

 desert-regions of Southern Africa they are repre- 

 sented by leafless, Cactus-like succulents (Stapelia). 

 Poisonous. — The latex of most of the Aselepia- 

 daeeae, and also all parts of the species Viiieetoxiewm 



officinale (Fig. 560), possess toxic principles. The latter is a small, inconspicuous, 



white-flowered plant, with capsules and long-haired seeds. 



Officinal. — The bark of Gonolobus Condurango and other lianes of Peru and 



Ecuador yield Cortex Condurango. 



Fig. 560. — Vincetoxicwn 



(J nat. size).— Poisoxops. 



Order 5. Tubiflorae 



Flowers hypogynous, ACTINOMORPHIC, sometimes slightly zygo- 

 morphic, generally with the formula K5, C5, A5, G(£) ; stamens com- 

 plete IN number, inserted on the corolla ; ovary bilocular (rarely 

 trilocular), with two ovules in each loculus ; loculi frequently cham- 

 bered by false dissepiments. Leaves alternate. 



In spite of the great difference in appearance, the structure of the 

 flowers proves the existence of a close affinity between the different 

 members of the order. The families included in the Tubiflorae 

 form the beginning of a series, which is further continued by the 

 families of the two next succeeding orders, the Personatae and Labiati- 

 florae. That the families of the Tubiflorae, in particular the Con- 

 volmlaceae, are the older, or have deviated less from the ancestral form, 

 is rendered probable from a comparison of their actinomorphic flowers 

 and pentamerous androecia with the zygomorphic flowers and reduced 



