APOCYNACEAE (DOGBANE FAMILY) 385 



94. APOCYNACEAE Lindl. Dogbane Family 



. Ferennial 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 6-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; anther^ linear-oblong, 

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

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

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



Leaves alternate; anthers free from the Btigma ;; ■ . . . I,' ATtiBoma. 

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

 herent to it 2, Apocynum. 



1, AMSONIA Walt. 



Herbs. Leaves alternate; blades entire. Flowers in terminal thyrsoidor 

 corymbose cjTnes. Caljfx-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 togethei", 

 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 

 naigrowly elhptic or linear, conspicuously narrower on the upper part of the 

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

 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 kaves. 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, triangiilar-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. androsaemifoliuml.' 

 Corolla greenish-white, its lobes mostly erect. 



Leaves petibled, 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. 175.3. 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 

 oyate-lanceolate, 2-2.5 mm. long: corolla pink, 5-7 mm. long; lobes revol'vite: 

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

 Baker. 16. 1901, the glabrate form.)-=— Throughout omi range, and very widely 

 diptriliuted 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 obloilg to ovate-bblong 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' 



