506 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



4. Apocynum laurinum Greene, Pittonia 5: 64. 1902. 



Type locality: Organ Mountains, New Mexico. Type collected by Wooton 

 (no. 113). 

 Range: Mountains of southern New Mexico. 

 New Mexico: Organ Mountains; Ruidoso Creek. 



5. Apocynum hypericifolium Ait. Hort. Kew. 1: 304. 1789. 

 Type locality: North America. 



Range: British America to Ohio and New Mexico. 



New Mexico: Mesilla Valley. River valleys, in the Lower and Upper Sonoran 

 zones. 



6. Apocynum viride Woot. & Standi. Contr. U. S. Nat. Herb. 16: 159. 1913. 

 Type locality: Gilmores Ranch on Eagle Creek, White Mountains, Lincoln County, 



New Mexico. Type collected by Wooton and Standley (no. 3451). 



Range: New Mexico. 



New Mexico: Farmington; Cedar Hill; Las Vegas; Pecos; Reserve; White and 

 Sacramento mountains. Wet ground, in the Upper Sonoran and Transition zones. 



7. Apocynum angustifolium Wooton, Contr. U. S. Nat. Herb. 16: 159. 1913. 

 Type locality: Gila River bottom near Cliff, Grant County, New Mexico. Type 



collected by Metcalfe (no. 132). 



Range: Southwestern New Mexico. 



New Mexico: Cliff; Mimbres; Lower Plaza; Eagle Creek. Along streams, in the 

 Upper Sonoran Zone. 



A very distinct species because of its very narrow bright green leaves, nearly all 

 of them acute at the base. ^ 



115. ASCLEPIADACEAE. Milkweed Family. 



Herbaceous perennials, erect or twining, mostly with milky juice; leaves simple, 

 alternate, opposite, or whorled, exstipulate, mostly entire; flowers perfect, regular, 

 mostly umbellate; calyx hypogynous, the tube very short or none, imbricated in 

 bud ; corolla 5-merous, campanulate, urceolate, rotate, or funnelform, the lobes com- 

 monly reflexed; a 5-lobed crown (corona) borne between the corolla and stamens 

 and adnate to one or both of them; stamens 5, adnate to the corolla usually near its 

 base, monadelphous or distinct; anthers converging around the stigmas, ■ sometimes 

 united to each other, the sacs tipped with an inflexed or erect scarious membrane 

 or not appendaged at the top, sometimes appendaged at the base; pollen in waxy 

 masses (pollinia) connected with the stigma in pairs; pistil of 2 carpels; styles 2, 

 with a single peltate discoid stigma; fruit a pair of several to many-seeded follicles; 

 seeds comose. 



KEY TO THE GENERA. 



Pollinia horizontal or nearly so; stigma sharply 5-angled, 



depressed ; twining vine 1. Vincetoxicum (p. 507). 



Pollinia pendulous; stigmas various; stems twining or 

 straight. 

 Crown double, the outer a shallow ring, the inner 

 consisting of 5 fleshy hoodlike scales; twining 



vines 2. Philibertella (p. 507). 



Crown single; erect, ascending, or procumbent herbs. 



Corolla lobes erect-spreading during anthesis; 



hoods of the crown pendulous or saccate 



at the base, curved upward, obtuse, 



crested within, at least in the upper part. 3. Asclepiodora (p. 508). 

 Corolla lobes reflexed during anthesis; hoods 

 various. 



