674 ASCLEPIADACEAE 



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

 long, obtuse at the apex, the rounded margins overlapping; follicles 5-7 cm. long, 

 lance-ovoid, acuminate, glabrous or minutely puberulent. 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; column about 1 mm. long; hood white, broadly ovate, truncate at 

 the apex, lobed on the sides near the base; follicles 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; follicles 5-7 cm. long, glabrous or 

 minutely puberulent, lanceolate. Dry plains: Tex. Kans. Colo. Calif.; 

 Mex. Son. Je-Au. 



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

 dm. high, simple; leaves very numerous, 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-spinulose. 



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, incurved, obtuse, 2-lobed on the ventral margin; follicles 

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

 soil: Kans. 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 stipules. Flowers perfect, regular, 

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

 Corolla gamopetalous, usually funnelform, either plicate and the plaits 

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



