674 ASCLEPIADACEAE 



white; lobes oblong, 4—6 mm. long; oolumn 1-1.5 mm. long, slender; hoods ob- 

 long, obtu.se at the apex, the roun<le(l intirgins overlapping; foUifles 5-7 cm. long, 

 lance-ovoid, acuminate, glabrous or minutely i)uberulent. The southwestern 

 plant is usually tall, over 1 m. high and with long, narrow leaves (var. longifolia 

 A. Gray). In swamps: N.B. — Fla. — N.M. — Wyo. — Man. Plain — Submont. 

 Je-Au. 



16. A. mexicana Cav. Stem 1-2 m. high, branched and woody at the base; 

 leaves verticillate in 3's to 6's, rarely opposite, short-petioled or subsessile; blades 

 linear or linear-lanceolate, 6-15 cm. long, glabrous; corolla ash-colored or rarely 

 greenish, tinged with purple; lobes oblong, 4 mm. long; column about 1 mm. 

 long; hood white, broadly ovate, without lobes; follicles linear-lanceolate, 6-8 

 cm. long, puberulent. Grassy slopes and valleys: Calif. — Wash. — Ida. — Ariz.; 

 Mex. Son. Ap-Au. 



17. A. verticillata L. Stem angled, glabrous or pubescent in lines, 4-10 

 dm. high; leaves narrowly linear to almost filiform, 5-10 cm. long, verticillate in 

 whorls of 2's to 4's; corolla greenish, sometimes tinged with purple; lobes oblong, 

 4 mm. long; colmnn about 1 mm. long; hood white, broadly ovate, truncate at 

 the apex, lobed on the sides near the base; folhcles linear-lanceolate, 7-10 cm. 

 long, glabrous or minutely puberulent. Dry and sterile soil: Me. — Fla. — Tex. 

 — Mex. — Ariz. — N.D. Plain — Son. Ap-Au. 



18. A. galioides H.B.K. Stem erect, solitary, glabrous or minutely puber- 

 ulent in lines, 4-10 dm. high; leaves in whorls of 3's to 6's, narrowly linear, 6-8 

 cm. long; corolla-lobes greenish white, oblong, obtuse, 4 mm. long; column 

 nearly 1 mm. long; hoods erect-spreading, broadly rounded at the apex, entire- 

 margined, hastate-sagittate on the back; folhcles 5-7 cm. long, glabrous or 

 minutely puberulent, lanceolate. Dry plains: Tex.^ — ^Kans. — Colo. — CaUf.; 

 Mex. Son. Je-Au. 



19. A. pumila (A. Gray) Vail. Stems tufted, glabrous or nearly so, 1-2.5 

 dm. high, simple; leaves very nmnerous, crowded, irregularly scattered on the 

 stem, about 3.5 cm. long, linear-filiform, revolute, glabrous or minutely scabrous- 

 puberulent; corolla greenish white; lobes oblong, 4-5 mm. long; column about 

 0.5 mm. long; hoods oblong, erect, entire; follicles narrowly lanceolate, 3-5 cm. 

 long, minutely puberulent. Dry plains: S.D. — Ark. — N.M. — Colo.— Mont. 

 Plain — Submont . Jl-S . 



5. ASCLEPIODORA A. Gray. Spider Milkweed. 



Perennial herbs. Leaves opposite or alternate. Flowers perfect, regular, 

 purplish, greenish, or white, in terminal, solitary or corymbose umbels. Calyx- 

 lobes narrow, acute. Corolla rotate, 5-lobed, the lobes acute, spreading or 

 erect. Hoods inserted over the whole short column, arising from the base of the 

 corolla-lobes, saccate at the base, obtuse at the apex, crested within, with 1 or 2 

 small appendages between the hoods, simulating an inner crown. Follicles fusi- 

 form, often soft-spimdose. 



1. A. decumbens (Nutt.) A. Gray. Perennial, with a woody rootstock; 

 stems usually several, 2-4 dm. high, angled; leaves 4-15 cm. long, lanceolate to 

 linear, attenuate, thick, alternate or whorled in 3's; corolla globose in bud; lobes 

 greenish; hood purplish, mcurved, obtuse, 2-lobed on the ventral margin; folhcles 

 about 8 cm. long, pubescent, smooth, or with a few soft processes. Dry sandy 

 soil: Ivans. — Ark. — Tex. — Ariz. — Nev.; Mex. Son. — -Submont. Je-S. 



Family 107. CONVOLVULACEAE. Morning-glory Family. 



Annual or perennial, twining or trailing herbs or vines, or rarely trees or 

 shrubs. Leaves alternate, without stipu^e.s. Flowers perfect, regular, 

 either solitary, axillary, or in cymes. Sepals 5, rarely 4, more or less united. 

 Corolla gamopetalous, usually funnelforni, either plicate and the plaits 

 convolute, or indiiplicate-valvate, rarely imbricate in the bud, 5-lobed, or 



