746 FLORA. 



Hoods obtuse, entire; column i mm. long; stem roughish, puberulent. 



3. A. Floridana. 



Hoods emarginate; column very short; stem glabrous. 4. A. auriculata. 



Plant hirsute; umbel solitary, terminal; leaves ovate to oblong. 5. A. lanuginosa. 



1. Acerates viridiflora (Raf.) Eaton. Green Milkweed. (I. F. f. 2924.) 

 Puberulent or tomentulose, at least when young; stems simple, reclined or ascend- 

 ing, rather stilt, 3-9 dm. high. Leaves slightly rough, alternate or opposite, 

 thick, 2.5-8 cm. long, 1.5-5 cm - wide, short-petioled, the margins usually undu- 

 late; umbels several, or rarely solitary, densely many-flowered; pedicels very slen- 

 der, tomentose; flowers green; corolla- segments narrowly oblong, 4-6 mm. long; 

 column very short or none; hoods lanceolate-oblong, obtuse, minutely 2-auricled a.\ 

 the base; mass of anthers longer than thick; anther-wings tapering below, semi, 

 rhomboid above; follicles puberulent, 5-10 cm. long. In dry, sandy or rocky soil, 

 Mass. to Ont., the N. W. Terr., Fla. and Tex. June-Sept. 



Acerates viridiflora Ivesii Britton. Leaves lanceolate or oblong-lanceolate, 5-ia 

 cm. long, 6-25 mm. wide. Range of the type, often with it. 



Acerates viridifl6ra linearis A. Gray. Leaves elongated-linear; stem low; umbeh 

 often solitary. Minn, and Manitoba to the N. W. Terr., La. and N. Mex. 



2. Acerates angustifdlia (Nutt.) Dec. Narrow-leaved Milkweed. (I. F. f. 

 2925.) Stems mostly several together, erect. 3-6 dm. high, puberulent above, 

 glabrate below. Leaves opposite, or some of the lower alternate, sessile, 5-13 cm. 

 long, glabrous, the revolute margins and the thick midvein rough beneath; umbels 

 10- 1 5 -flowered, usually numerous; pedicels puberulentt corolla-segments oblong, 

 greenish; hoods white, not exceeding the anthers, the acute middle tooth merely a 

 prolongation of the thickened crest-like midvein, shorter than the obtuse lateral 

 ones; anther-wings notched at about the middle; follicles slender, erect, about 8 cm. 

 long or more. On dry plains, Mo. to Neb., Colo, and Tex. 



3. Acerates Floridana (Lam.) Hitchc. Florida Milkweed. (I. F. f. 

 2926.) Stem slender, simple or little branched, 3-9 dm. high. Leaves linear or 

 rarely linear-lanceolate, acute or acuminate, short-petioled, 5-20 cm. long, 

 3-13 cm. wide, commonly rough ciliolate on the margins and midrib; umbels 

 usually many-flowered; peduncles 6-20 mm. long; pedicels slender, hirsute; 

 corolla greenish-white, its segments narrowly oblong, about 4 mm. long; column 

 distinct; hoods oblong, shorter than the anthers; anther-wings narrowed to the 

 base; follicles densely puberulent, 10-13 cm> l° n g- * n m oist s °il> Chio to southern 

 Ont., Minn., N. Car., Fla. and Tex. June-Sept. [A. longi folia Ell.] 



4. Acerates auriculata Engelm. Auricled Milkweed. (I. F. f. 2927.) 

 Stem often glaucous, sinuous above, usually stout, 3-9 dm. high. Leaves nar- 

 rowly linear, glabrous, short-petioled, 8-20 cm. long, 1-5 mm. wide, becoming 

 leathery, the rough margins not revolute; umbels commonly several, densely many- 

 flowered; peduncles 4-25 mm. long, pubescent: pedicels slender, pubescent; flowers 

 greenish white, tinged with dull purple; corolla-segments oblong, 4-5 mm. long; 

 column distinct; hoods yellow, often with a purplish keel, truncate at the apex, 

 not exceeding the anthers, the involute margins spreading at the base into broad 

 auricles; follicles 5-8 cm. long, curved. In dry soil, Neb. and Colo, to Tex. and 

 N. Mex. June-Sept. 



5. Acerates lanuginosa (Nutt.) Dec. Woolly Milkweed. (I. F. f. 2928.) 

 Stems erect, slender, simple, 1.5-4 dm. high. Leaves obtuse at the apex, nar- 

 rowed <>r rounded at the base, short-petioled, 3-10 cm. long; umbel densely many- 

 Bo wered; peduncle stout, densely hirsute, 1.2-4 cm - long; pedicels slender, puber- 

 ulent or hirsute; corolla greenish, its segments oblong, about 5 mm. long; column 

 none; hoods purplish, oblong, obtuse, entire, with a flat fold or auricle on the 

 infolded lower ventral margins, shorter than the anthers; anther-wings broadest 

 below the middle. On prairies, 111. to Minn, and Wyo. June-Aug. 



4. GONOLOBUS Michx. 



(AMI'ELANUS Raf.) 



Perennial herbaceous vines, with petioled opposite cordate thin leaves, and 

 small whitish flowers in axillary cymes. Calyx 5-parted, minutely glandular 



