PHANEROGAMIA 575 



The plants included in this family are large or small, glabrous 

 herbs. Their leaves, which are almost always opposite and entire, are 

 destitute of stipules. The flowers are often large and highly coloured, 

 terminal and solitary, or more frequently they are arranged in di- 

 chasial inflorescences. The fruit is a two-valved, many-seeded capsule. 

 Many species of Gentianaceae are rich in bitter principles. 



Representative Genera.— Gentiana (Gentian), with straight anthers ; Ery- 

 thraea (Centaury), with anthers spirally twisted ; Ohlora (Yellow- wort) ; Menyanthes 

 (Buckbean), with scattered, ternate leaves. 



Officinal. — Gentiana lutea (Fig. 555), and G. pannonica, punctata, purpurea, 

 yield Radix Gentianae ; Erythraea Centaurium (Fig. 556), Herba Centaurii ; 

 Menyanthes trifoliata, Folia Trifolii fierini. 



Fig. 559. — Asclepias curassavica. A, Flower ; an, andriiicium (x 4) ; B, calyx and gynoeciuni ; 

 fn, ovary ; 1c, eorpuscula ( x 6) ; C, pollinia (magnified). (After Baillon.) 



Family Apocynaceae. — Corolla with contorted estivation ; 

 andrcecium haplostemonous ; pollen granular or in tetrads ; carpels 

 usually free below ; ring-shaped STIGMA. Plants with latex (Fia;s. 

 557, 558). 



In this family are represented perennial herbs, shrubs, lianes, and trees ; all 

 usually evergreen, With opposite, entire leaves. The rotate or funnel-shaped 

 flowers, which are often large and conspicuous, are aggregated in cymose inflores- 

 cences ; the fruit is usually a capsule, both of whose free carpels (follicles) dehisce 

 along the ventral suture, setting free numerous and often hairy seeds to be 

 disseminated by the wind. 



Geographical Distribution. — The Apocynaceae are chiefly indigenous to the 

 Tropics, where numerous species are found. Familiar examples of this family are 

 afforded by the Oleander, Nerium Oleander, and Periwinkle, Vinca minor (Fig. 

 557). 



Poisonous. — Nerium Oleander (Fig. 558), an evergreen shrub of Southern 

 Europe, with lanceolate leaves and large rose-coloured, more rarely white or light 

 yellow, fragrant flowers. All parts of the Oleander are poisonous. 



Officinal. — Various species of Strophanthus (e.g. S. hispidus), tropical lianes 

 of Western Africa, yield Semen Strophanthi. From Aspidosperma Quehracho, a 

 tree native of the Argentine Republic, is derived Cortex Quebracho. 



