292 



GENTIANACEAE. 



hiseent by 2 valves. Endosperm fleshy, copious; embryo small, terete or 

 conic. About 70 genera and 700 species, widely distributed. 



1. CENTAURIUM Hill. 

 Herbs, mostly annual or biennial, with sessile or amplexicaul leaves, and 

 pink white or yellow flowers in cymes or spikes. Calyx tubular, 5-4-lobed 

 or -divided, the lobes or segments narrow, keeled. Corolla salverform, 5-4' 

 lobed, the lobes spreading, contorted, convolute in the bud. Stamens 5 or 4, 

 inserted on the corolla-tube; filaments short-filiform; anthers becoming spirally 

 twisted. Ovary 1-celled, the placentae sometimes intruded; style filiform; 

 stigma 2-lobed. Capsule 2-valved. Seed-coat reticulated. [Greek, red, the 

 color of the flowers in some species.] About 25 species, natives of the Old 

 World and western North and South America. Type species: Gentiana 

 Centaurium L. 



1. Centaurium pulchellum (Sw.) 

 Druce. Branching Centaury. (Fig. 

 311.) Glabrous, much branched, 3'-8' 

 high. Leaves oval, ovate or lanceolate, 

 the lower mostly obtuse, 3"-8" long; no 

 basal tuft of leaves; flowers pink, cy- 

 mose-paniculate, all or nearly all of 

 them pedicelled, 5"-6" long; tube of the 

 corolla li-2 times longer than the calyx- 

 segments, its lobes oblong, obtuse, li"- 

 2" long; stigma oval. [Gentiana pul- 

 chella Sw.; Erythraea pulchella Fries; 

 E. Centaurium of Reade, Lefroy, H. B. 

 Small and Kemp; E. texensis of Hems- 

 ley.] 



Frequent in waste grounds. Natural- 

 ized. Native of Europe. Naturalized in 

 the eastern United States. Flowers from spring to autumn, ^'i-f 'Zl!a ^'''■" 

 This is, probably, the plant recorded by Michaux, m 1806, as Gentiana nana. 



Family 4. APOCYNACEAE Lindl. 



Dogbane Family. 



Perennial herbs, shrubs, vines, or some tropical genera trees, mostly 

 with an acrid milky juice, with simple estipulate leaves, and perfect regular 

 5-parted flowers. Calyx inferior, persistent, the lobes imbricated m the 

 bud. Corolla gamopetalous, its lobes convolute m the bud and otten 

 twisted. Stamens as many as the lobes of the corolla, alternate with them, 

 inserted on the tube or throat; anthers 2-celled; pollen-grams simple. 

 Ovary superior, or its base adherent to the calyx, of 2 distinct carpels, or 

 1-celled, with 2 parietal placentae, or 2-celled; ovules anatropous or am- 

 phitropous; style simple, or 2-divided; stigma simple. Fruit usually ot J 

 follicles or drupes. Seeds often appendaged; endosperm Aesby '' ^i^^!^^ 

 straight; radicle terete, usually shorter than the cotyledons. About IdU 

 genera and 1100 species, very widely distributed, mostly m tropical regions. 



