APOCYNACEAE. 269 



Order 43. ASCLEPIADALES. 



Styles united ; stamens distinct or gynandrous ; pollen loosely granular. 



109. Apocynaceae. 

 Styles distinct ; stamens monadelphous ; pollen united into waxy masses or the 

 grains in groups of 4. no. Asclepiadaceae. 



Family 109. APOCYNACEAE Lindl. Dogbane Family. 



.\nthers unappendaged at the base, not connected with the stigma ; flowers without 

 a disk; leaves alternate. i. Amsonia. 



Anthers appendaged at the base, converging around the stigma and slightly 

 adhering to it ; calyx-tube partly attached to the gynoecium by the thick disk ; 

 leaves opposite. 2. Apocynum. 



I. AMSONIA Walt. 



I. Amsonia texana (A. Gray) Heller. (A. angustifolia texana A. Gray) 

 In rocky places from Texas to Colo. — Grand Junction. 



2. APOCYNUM L. DoGBONE, Indian Hemp. 



Corolla fully twice as long as the calyx ; its lobes spreading in anthesis. 

 Leaves more or less pubescent beneath. 



Sepals broadly lanceolate ; corolla open campanulate ; leaves thick, dark 

 green, decidedly pubescent beneath. 

 Leaves oval, acute at both ends ; plant usually tall. 



I. A. androseniaefolium. 

 Leaves more or less ovate, rounded, truncate, or cordate at the base ; 

 plant low, diffuse. 2. A. scopulorum. 



Sepals narrowly lanceolate ; corolla narrower, almost cylindro-campanulate ; 

 leaves pale green, pubescent merely on the petioles and the veins beneath, 

 the lower truncate, the upper acute at the base. 3. A. lividum. 

 Leaves perfectly glabrous. 4. A. ambigetts. 



Corolla less than twice as long as the calyx ; its lobes erect or nearly so. 

 Leaves acute at the base, petioled. 5. A. cannabinum. 



Leaves, at least those of the main stem, truncate or subcordate at the base and 

 subsessile. 6. A. hypericifoliuiii. 



1. Apocynum androsemaefolium L. In copses and borders of woods from 

 Anticosti and Ida. to Ga. and Ariz. — Alt. 7000-9500 ft. — Artist's Glen; Engel- 

 mann Caiion ; Wahatoya Creek ; mountains, Larimer Co. ; Stove Prairie 

 Hill ; Horsetooth. 



2. Apocynum scopulorum Greene. In the mountains from Sask. and Yukon 

 to Colo. — Alt. 5000-9000 ft.- — Pagosa Springs ; Mancos ; Roger's, Gunnison 

 watershed. 



3. Apocynum lividum Greene. In the mountains of Colo.- — Alt. 5000-8000 

 ft. — Black Caiion; mouth of Cheyenne Cafion; Mancos; Piedra ; Palisade; 

 Clear Creek Cafion; Ft. Collins. 



4. Apocynum ambigens Greene. In the mountains from Mont, and Wash, 

 to Colo, and Calif. — Alt. 6000-9000 ft. — West of Ouray; Black Caiion; 

 Boulder Cafion ; Rist Caiion ; Horsetooth Mountain ; Montrose ; Steamboat 

 Springs. 



5. Apocynum cannabinum L. On banks of streams from Anticosti and 

 Wash, to Fla. and L. Calif. — Alt. 4000-5000 ft. — Deer River; New Windsor, 

 Weld Co.; Boulder; along the Poudre; Ft. Collins. 



6. Apocynum hypericifolium Ait. In sandy soil from Ont. and B. C. 

 to Ohio and N. M. — Alt. 5000-6000 ft. — Plains and foot-hills near Boulder. 



