504 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



114. APOCYNACEAE. Dogbane Family. 



Perennial herbs with milky sap; leaves opposite or alternate, sessile or short- 

 petiolate, simple, usually entire, exstipulate; flowers perfect, regular, in terminal 

 cymes; calyx 5-parted, persistent; corolla 5-parted; stamens as many as the corolla 

 lobes and alternate with them, inserted in the tube or throat of the corolla; anthers 

 linear ('Idling, sagittate, 2-celled; ovary superior or partly inferior, of 2 distinct carpels; 

 fruit of paired follicles; seeds often comose. 



KEY TO THE GENERA. 



Leaves alternate; anthers free from the stigma; corolla 10mm. 



long or more, tubular or funnelform 1. Amsonta (p. 504). 



Leaves opposite; anthers converging about the stigma and 



slightly adherent to it; corolla 3 to 5 mm. long, short- 



eampanulate or urceolate 2. Apocynum (p. 505). 



1. AMSONIA Walt. 



Herbaceous perennials, sometimes woody at the base, with alternate entire narrow 

 leaves and tubular or salverform flowers in terminal cymes; calyx lobes 5, acuminate; 

 disk wanting; corolla 1 cm. long or more, the tube narrow below, slightly enlarged 

 above, villous within; stamens included, not appendaged; carpels 2, connected by 

 the slender styles; stigma appendaged by a reflexed membrane; follicles erect, several- 

 seeded, the seeds pot appendaged. 



KEY TO THE SPECIES. 



Stems and leaves glabrous. 



Pods constricted between the seeds; corolla tube about 1 cm. 



long 1. A. brevifolia. 



Pods continuous, not constricted ; c< irolla tube 3 to 4 cm. long 4. A. longiflora. 



Stems and leaves variously pubescent. 



Pods constricted between the seeds; plants tomentose 2. A. armaria. 



Pods continuous, not constricted; plants hirtellous 3. A. hirtella. 



1. Amsonia brevifolia A. Gray, Proc. Amer. Acad. 12: 64. 1876. 



Type locality: "S. Utah and W. Arizona, to the border of California." 



Range: Southern California to Utah and northwestern New Mexico. 



N bw Mexico: Zuni (Stevenson 53). Dry soil, in the Upper Sonoran Zone. 



2. Amsonia arenaria Standley, Proc. Biol. Soc. Washington 26: 117. 1913. 



Type locality: Sandhills between Strauss and Anapra, near the southeast corner 

 of Dona Ana County, New Mexico. Type collected by Elmer Stearns (no. 372). 



Range: Southern New Mexico to northern Chihuahua. 



New Mexico: Between Strauss and Anapra; San Andreas Mountains. Sandhills, 

 in the Lower Sonoran Zone. 



3. Amsonia hirtella Standley, Proc. Biol. Soc. Washington 26: 118. 1913. 



Type locality: Near the Upper Corner Monument, southern Grant County, New 

 Mexico. Type collected by E. A. Mearns (no. 117). 



Range: Western Texas and southern New Mexico to Chihuahua. 



New Mexico: Grant County (Mearns 117). Dry hills, in the Lower Sonoran Zone. 



4. Amsonia longiflora Torr. U. S. ct Mex. Bound. Bot. 159. 1859. 

 Type locality: "Rocky ravines mar El Paso,'' Chihuahua or Texas. 

 Range: Southern New Mexico and western Texas to northern Mexico. 

 New Mexico: Rio Gila { Wooton). 



The specimen is in fruit only, but it has the leaves and the glabrous stems of this 

 species. 



