8. A. Sullivantii, Engelm. _Very smooth_ throughout, tall; leaves ovate-oblong with a somewhat heart-shaped base, nearly sessile; _hoods obovate_, entire, _obtusely 2-eared at the base_ outside; flowers larger (9" long) and more purple than in the last; anther-wings 2-toothed at base; _pod_ nearly glabrous, obscurely _spiny chiefly on the beak_.--Low grounds, Ohio to Kan. and Minn.

[+][+] _Follicles wholly unarmed, either glabrous or tomentulose-p.u.b.escent_.

[++] _Erect or ascending on the deflexed or decurved fruiting pedicels._

[=] _Umbel solitary, on a naked terminal peduncle; leaves sessile, broad, transversely veined, wavy; glabrous and pale or glaucous._

9. A. Obtusiflia, Michx. Stem 2--3 high; _leaves oblong with a heart-shaped clasping base_, very obtuse or retuse (2--5' long); peduncle 3--12' long; corolla pale greenish purple; hoods truncate, somewhat toothed at the summit, shorter than the slender awl-pointed horn.--Sandy woods and fields, not rare, especially southward. A second umbel at the base of the peduncle occasionally occurs.

10. A. Meadii, Torr. Stem slender (1--2 high); leaves _ovate or oblong-ovate_, obtuse or acutish (1--2' long), peduncle only twice the length of the upper leaves, pedicels rather short, corolla greenish-white; hoods rounded-truncate at summit, and with a sharp tooth at each margin, somewhat exceeding the stouter horn.--Dry ground, Ill.

and Iowa. June.

[=][=] _Umbels mostly more than one; peduncle not overtopping the leaves._

[a.] _Leaves large, orbicular to oblong-lanceolate; hoods broad, little if at all exceeding the anthers; glabrous or some minute p.u.b.escence on young parts._

11. A. Jamesii, Torr. Stem stout (1 high or more); leaves about 5 pairs, approximate, _remarkably thick, rounded or broadly oval, often emarginate, subcordate at base, nearly sessile_; umbels 2--3, densely many-flowered, on short peduncles, corolla-lobes ovate, _greenish_; hoods truncate, entire.--Plains of central Kansas and southwestward.

12. A. phytolaccodes, Pursh. (POKE-MILKWEED.) Stem 3--5 high; _leaves broadly ovate, or the upper oval-lanceolate and pointed at both ends, short-petioled_, smooth or slightly downy underneath (5--8' long); lateral umbels several, _pedicels loose and nodding, numerous, long_ and slender (1--3' long), equalling the peduncle; _corolla-lobes_ ovate-oblong, greenish; hoods (white) truncate, the margins 2-toothed at the summit, _the horn with a long projecting awl-shaped point_.--Moist copses, N. Eng. to Minn., south to Ga. and Ark.

13. A. variegata, L. Stem 1--2 high; _leaves_ (4--5 pairs) _ovate, oval, or obovate_, somewhat wavy, _contracted into short petioles_, middle ones sometimes whorled; _pedicels (numerous and crowded) and peduncle short, downy_; divisions of the _corolla ovate (white)_; hoods...o...b..cular, entire, purplish or reddish, the horn semilunar with a horizontal point.--Dry woods, southern N. Y. to Ind., south to Fla., Ark., and W. La. July.--Remarkable for its compact umbels of nearly white flowers.

[b.] _Leaves mostly p.u.b.escent or p.u.b.erulent; hoods obtuse, entire, twice or thrice the length of the anthers._

14. A. ovaliflia, Decaisne. Low (6--18' high), soft-downy, especially the lower surface of the ovate or lanceolate-oblong acute short-petioled leaves (1--3' long); umbels loosely 10--18-flowered, sessile or peduncled; pedicels slender, hoods oblong, yellowish, with a small horn, about the length of the oval greenish-white corolla-lobes (tinged with purple outside).--Prairies and oak-openings, N. Ill. and Iowa, to Wisc.

and Dak.

[++][++] _Follicles and pedicels erect; leaves often whorled; glabrous or nearly so._

[=] _Leaves ovate to broadly lanceolate, thin, rather slender-petioled._

15. A. quadriflia, L. Stem slender (1--2 high), mostly leafless below, bearing usually _one or two whorls_ of four in the middle and one or two pairs _of ovate or ovate-lanceolate_ taper-pointed petioled leaves (2--4' long); pedicels slender; corolla-lobes (_pale pink_) oblong; hoods white, elliptical-ovate, the incurved horn short and thick.--Dry woods and hills, N. Eng. to Minn., south to N. C. and Ark.

16. A. perennis, Walt. Stems (1--2 high) _persistent or somewhat woody at the base; leaves lanceolate or lanceolate-ovate, tapering to both ends_, thin, rather slender-petioled; _flowers white_, small; the small hoods of the crown shorter than the needle-shaped horn; seeds sometimes dest.i.tute of a coma!--Low grounds, S. Ind. and Ill. to Tex., and eastward.

[=][=] _Leaves narrowly linear to filiform; horn subulate, exserted; column conspicuous._

17. A. verticillata, L. Stems slender, simple or sparingly branched, very leafy to the summit, leaves filiform-linear, with revolute margins (2--3' long, 1" wide), 3--6 in a whorl; umbels small, lateral and terminal; divisions of the corolla ovate (greenish-white); hoods roundish-oval, about half the length of the incurved claw-shaped horns.--Dry hills, common, especially southward.--Var. PuMILA, Gray, is low and many-stemmed from a fascicled root; leaves much crowded, filiform.--Dry plains, Neb. to Kan. and N. Mex.

-- 2. _Anther-wings broadly rounded at base and conspicuously auriculate-notched just above it; hoods with a minute horn exserted from the 2-lobed apex._

18. A. stenophlla, Gray. p.u.b.erulent, but foliage glabrous; stems slender (1--2 high), leaves narrowly linear (3--7' long, 1--2" wide), the upper alternate, lower opposite; umbels several, short-peduncled, 10--15-flowered; corolla-lobes oblong, greenish; hoods whitish, equalling the anthers, conduplicate-concave; follicles erect on ascending pedicels.--Dry prairies, Neb. to E. Kan., south and westward.

3. ACERaTES, Ell. GREEN MILKWEED.

Nearly as in Asclepias; but the hoods dest.i.tute of crest or horn (whence the name, from a privative, and ???a?, _a horn_).--Flowers greenish, in compact many-flowered umbels. Leaves opposite or irregularly alternate, short-petioled or sessile. Pollen-ma.s.ses slender-stalked. Follicles smooth, slender.

[*] _Crown upon a short column and shorter than the globular ma.s.s of anthers and stigma, leaves mainly alternate-scattered._

1. A. longiflia, Ell. Minutely roughish-hairy or smoothish; stem erect (1--3 high), very leafy; leaves linear (3--7' long); umbels lateral, on peduncles of about the length of the slender pedicels; flowers 3" long when expanded.--Moist prairies and pine-barrens, Ohio to Minn., south to Fla. and Tex. July--Oct.

[*][*] _Crown sessile, the oblong hoods nearly equalling the anthers; leaves often opposite and broader._

2. A. viridiflra, Ell. Minutely _soft-downy, becoming smoothish_; stems ascending (1--2 high); leaves oval to linear, thick (1--4' long); _umbels nearly sessile, lateral_, dense and globose; flower (when the corolla is reflexed) nearly ' long, short-pedicelled.--Dry soil, common, especially southward. July--Sept.--Runs into var. LANCEOLaTA, Gray, with lanceolate leaves 2--4' long;--and var. LINEaRIS, Gray, with elongated linear leaves and low stems; umbels often solitary. The latter form from Minn., Dak., and southward.

3. A. lanuginsa, Decaisne. _Hairy_, low (5--12' high); leaves lanceolate or ovate-lanceolate; _umbel solitary and terminal, peduncled_; flowers smaller; _pedicels slender_.--Prairies, N. Ill. to Minn., and westward. July.

4. ENSLeNIA, Nutt.

Calyx 5-parted. Corolla 5-parted; the divisions erect, ovate-lanceolate.

Crown of 5 free membranaceous leaflets, which are truncate or obscurely lobed at the apex, where they bear a pair of flexuous awns united at base. Anthers nearly as in Asclepias; pollen-ma.s.ses oblong, obtuse at both ends, fixed below the summit of the stigma to the descending glands. Follicles oblong-lanceolate, smooth. Seeds with a tuft, as in Asclepias.--A perennial twining herb, smooth, with opposite heart-ovate and pointed long-petioled leaves, and small whitish flowers in raceme-like cl.u.s.ters, on slender axillary peduncles. (Dedicated to _A.

Enslen_, an Austrian botanist who collected in the Southern United States early in the present century.)

1. E. albida, Nutt. Climbing 8--12 high; leaves 3--5'

wide.--River-banks, S. Penn. and Va. to Ill., Mo., and Tex. July--Sept.

5. VINCEToXIc.u.m, Moench.

Calyx 5-parted. Corolla 5-parted, wheel-shaped. Crown flat and fleshy, disk-like, 5--10-lobed, simple. Anthers, smooth follicles and seeds much as in Asclepias.--Herbs, often twining. (Name from _vincens_, binding, and _toxic.u.m_, poison.)

V. NGRUM, Moench. More or less twining, nearly smooth; leaves ovate or lance-ovate; flowers small, dark purple, in an axillary cl.u.s.ter, on a peduncle shorter than the leaves.--N. Eng. to Penn.; a weed escaping from gardens. (Adv. from Eu.)

6. GONoLOBUS, Michx.

Calyx 5-parted. Corolla 5-parted, wheel-shaped, sometimes reflexed-spreading; the lobes convolute in the bud. Crown small and fleshy, annular or cup-shaped, in the throat of the corolla. Anthers horizontal, partly hidden under the flattened stigma, opening transversely. Pollen-ma.s.ses 5 pairs, horizontal. Follicles turgid, mostly muricate with soft warty projections, sometimes ribbed. Seeds with a coma.--Twining herbs or shrubs (ours herbaceous), with opposite heart-shaped leaves, and corymbose-umbelled greenish or dark purple flowers, on peduncles rising from between the petioles. Our species belong to the typical section, with the crown simple and unappendaged, and the corolla nearly veinless. (Name composed of ????a, _an angle_, and ????, _a pod_, from the angled follicles of some species.)

[*] _Crown a low undulately 10-lobed fleshy disk; follicles unarmed, glabrous, 3--5-costate or angled._

1. G. subersus, R. Br. Leaves cordate with an open shallow or sometimes deeper and narrow sinus, pointed, glabrate or hairy (3--5' long); umbels 3--9-flowered, much shorter than the petiole; _corolla broadly conical in bud, abruptly pointed, twisted; lobes ovate_ or triangular-lanceolate, _acute, p.u.b.escent inside; calyx half as long_.

(G. macrophyllus, _Chapman_.)--Near the coast, Va. to Fla.

2. G. lae'vis, Michx. Leaves oblong-cordate with a deep and narrow open sinus, conspicuously ac.u.minate (3--6' long); umbels 5--10-flowered, barely equalling the petiole; _corolla elongated-conical in bud, not twisted; lobes narrowly or linear-lanceolate, obtuse, glabrous inside, 3--4 times as long as the calyx_.--South of our range.--Pa.s.ses into var.

MACROPHLLUS, Gray, with _larger_ broadly cordate _leaves_, the _sinus often closed_, finely p.u.b.escent beneath. (G. macrophyllus, _Michx._)--River-banks, Va. to S. Ind., Mo., S. C., and Tex.

[*][*] _Crown cup-shaped, as high as the anthers; follicles muricate, not costate._

[+] _Crown fleshy, merely 10-crenate, or the crenatures bidentate._

3. G. oblquus, R. Br. Leaves rounded- to ovate-cordate with a narrow sinus, abruptly ac.u.minate (3--8' long); _umbel many-flowered; corolla in bud oblong-conical; its lobes linear-ligulate_ (5--6" long, 1" wide), crimson-purple inside, dull or greenish and _minutely p.u.b.escent outside_.--River-banks, mountains of Penn. and Va., to Ohio and Mo.

Flowers said to be fragrant.

4. G. hirsutus, Michx. Commonly more hairy; leaves with the basal lobes sometimes overlapping; _peduncles fewer-flowered; corolla in bud ovate, its lobes elliptical-oblong_ (3--4" long), _barely p.u.b.erulent outside_, dull or brownish-purple.--Md. and Va. to Tenn. and Fla.

[+][+] _Crown thinner, the border lobed or toothed; leaves as in the preceding._