APOCYNACEAE (DOGBANE FAMILY) 385 



94. APOCYNACEAE Lindl. DOGBANE FAMILY 



Perennial herbs (ours), mostly with acrid, milky juice, simple, opposite or 

 alternate leaves, and perfect, regular, cymose, solitary, or paniculate flowers. 

 Calyx 5-parted, persistent, the lobes imbricated in the bud. Corolla 5-parted, 

 the lobes convolute in the bud. Stamens as many as the lobes of the corolla 

 and alternate with them, inserted in the tube or throat ; anthers linear-oblong, 

 sagittate, 2-celled. Ovary superior or its base adherent to the calyx, of 2 

 distinct carpels; ovules few or numerous; style simple or 2-divided; stigma 

 simple. Fruit of 2 follicles. Seeds often appendaged by a coma. 



Leaves alternate; anthers free from the stigma 1. Amsonia. 



Leaves opposite; anthers converging around the stigma and slightly ad- 

 herent to it 'tv ."<; ...,' . . . . . .2. Apocynum. 



1. AMSONIA Walt. 



Herbs. Leaves alternate; blades entire. Flowers in terminal thyrsoid or 

 corymbose cymes. Calyx-lobes 5, acuminate ; disk wanting. Corolla mainly 

 salverform; tube slightly dilated upward, villous within; lobes narrow. Sta- 

 mens included; anthers unappendaged. Carpels 2, connected by the slender 

 styles; stigma appendaged by a reflexed membrane. Follicles 2 together, 

 erect, several-seeded. Seeds unappendaged. 



1. Amsonia texana (Gray) Heller, Muhl. 1: 2. 1900. Stems 1.5-7 dm. 

 tall, often sparingly branched, glabrous: leaves numerous; blades oblong to 

 narrowly elliptic or linear, conspicuously narrower on the upper part of the 

 plant, 2.5-6 cm. long, acute or blunt, often somewhat lustrous above, glabrous 

 at least at maturity: calyx-lobes acuminate, the longer about 2 mm. long: 

 corolla glabrous; tube 9- 11 mm. long; lobes usually about as long as the tube: 

 follicles 6-10 cm. long, glabrous. Colorado to Texas. 



2. APOCYNUM L. DOGBANE. INDIAN HEMP 



Pale perennial herbs, with very tough-fibrous bark and opposite mucronate- 

 tipped leaves. Flowers small, in terminal cymes, white or rose-color. Calyx 

 small, deeply 5-cleft, the tube by means of a thickish disk adnate to the back 

 of the ovaries below. Corolla campanulate, 5-lobed, toward the base bearing 

 5 small, triangular-subulate appendages alternate with the stamens. Fila- 

 ments very short and broad; anthers sagittate. Follicles slender, 5-15 cm. 

 long, terete. Seeds numerous, with a long coma at apex. 



Corolla pink, its lobes spreading or revolute . . . 1. A. androsaemifolium. 



Corolla greenish-white, its lobes mostly erect. 



Leaves petioled, cuneate or cuneately rounded at base . 2. A. cannabinum. 



Leaves sessile or nearly so, subcordate or broadly rounded at 



base . . . .'..'. . . .3. A. hypericifolium. 



1. Apocynum androsaemifolium L. Sp. 213. 1753. Stems 3-15 dm. tall, 

 with widely-spreading branches, mostly glabrous: leaf-blades ovate, oblong 

 or oval, 4-11 cm. long, deep green and glabrous above, pale and more or less 

 pubescent beneath, short-petioled : cymes rather lax: calyx-lobes ovate to 

 ovate-lanceolate, 2-2.5 mm. long: corolla pink, 5-7 mm. long; lobes revolute: 

 follicles 10-15 cm. long. (A. scopulorum Greene; A. ambigens Greene, PI. 

 Baker. 16. 1901, the glabrate form.) Throughout our range, and very widely 

 distributed in the United States. 



2. Apocynum cannabinum L. 1. c. Stems 8-18 dm. tall, the branches erect 

 or ascending, glabrous at maturity: leaf -blades oblong to ovate-oblong or 

 oblong-lanceolate, 5-12 cm. long, glabrous, or slightly pubescent beneath, 

 short-petioled: cymes rather dense: calyx-lobes lanceolate, 2.5-3 mm. long: 



ROCKY MT. EOT. 25 



