Plants (chiefly herbs in the United States) with a milky juice, often twining.

Leaves opposite (rarely whorled or scattered), without stipules, entire. Flowers generally umbellate, 5-parted, regular, the sepals and also the petals united at base, both valvate in aestivation. Stamens united, adherent to and covering the fleshy mass of the two united stigmas. Pollen cohering in masses. Ovaries 2, forming follicles in fruit.

Genera 141, xpecies 910, chiefly natives of tropical regions, and especially abundant in S. Africa, 8. India and New Holland, but are not uncommon in temperate regions.

Properties. - Similar to those of the Apocyna-ccae but far less active. The juice is acrid and generally to be, at least, suspected. A few of the species are medicinal, but none, of much consequence.

FIG. 670.   1. Asclepias cornuti

FIG. 670. - 1. Asclepias cornuti. 2. A flower, the petals and sepals reflexed, and the corona erect. 3. One of the segments of the corona with the horn bent inwardly. 4. A pair of pollen masses suspended from the glands. 5. A mature follicle. 6. Vertical section of P. phytolacoides showing the 2 ovaries. 7. Lohe and horn of the corona.

Tribes And Genera

I

PERIPLOCEae. Filaments distinct. Pollinia single (not in pairs), granular. (*)

* Anthers bearded on the back. Pollinia 5. Stem twining................

PERIPLOCA.

1

II

ASCLEPIADEae. Filaments connate. Pollinia 10, in pairs, pendulous, vertical, (a)

a Hoods each sheathing a little horn. Petals reflexed............................

ASCLEPIAS.

2

a Hoods of the crown destitute of a horn, (b)

b Petals reflexed. Hoods erect, adnate to the anthers................

ACEEATES.

3

b Petals expanding. Hoods ascending, free from anthers.....................................

ANANTHERIX.

4

b Petals erect. - Plant erect. Anther head pedicellate...........................................

Podostigma.

5

- Plants twining. Crown fleshy retuse..........................................

SENTERA.

6

- Plant twining. Crown thin, 2-awned........................................

ENSLENIA.

7

III

GONOLOBEae. Filaments connate, Pollinia 10, in pairs, horizontal, (c)

c Corolla wheel - shaped. Plants twining, with cordate leaves....................

Gomolobus.

8

IV.

STAPELIEae. Filaments connate. Pollinia 10, ascending or erect, (d)

d Crown simple, of 5 fleshy segments. Twining. Cultivated.............

HOYA.

9

d Crown double, an outer and an inner. Not twining. Cultivated........

Stapelia.

10

1. PERIP'LOCA, L. (Gr.Tribes And Genera 1450 around, Tribes And Genera 1451 a binding or twining; from the habit of the plant.) Calyx minute; corolla rotate, flat, 5-parted, orifice surrounded by a 5-cleft, urceolate corona, terminating in 5 filiform awns; filaments distinct, anthers cohering, bearded on the back; pollinia solitary, 4-lobed; follicles 2, smooth, divaricate; seeds comous. - Twining shrubs. Fls. in umbels or cymes.

P. Graeca L. Lvs. ovate, acuminate; corymbs axillary; cor. villous within. - A climbing shrub, 10 - 15f long, sparingly naturalized in Western N. Y., also cultivated in gardens. Leaves opposite, 3 - 4' long, 1/3 as wide, and on petioles 1/3' long. Flowers in long, branching, axillary peduncles. Sepals minute, lanceolate, acute. Petals very hairy within, linear, obtuse, dark purple. Follicles about 2' long. Aug. § S. Eur.

2. ASCLE'PIAS, L. Milk weed. (From Esculapius, the fabulous god of medicine and physicians.) Calyx deeply 5-parted; corolla deeply 5-parted, valvate in aestivation, finally reflexed; staminal corona 5-leaved, leaflets cucullate, with an averted horn-like process from the base curved towards the stigma; antheridium (connate mass of anthers) 5-angled, truncate, opening by 5 longitudinal fissures; pollinia (masses of pollen) 5 distinct pairs fixed by the attenuated apex to a cleft gland, pendulous; follicles 2, ventricous; seeds comous. -Tribes And Genera 1452 Mostly N. American, with opposite, verticillate, rarely alternate lvs. Umbels between the petioles.

§ Leaves linear, long and narrow (lance-linear in the cultivated No. 19). (*)

* Leaves all opposite, or rarely the lighest alternate......................................

Nos. 17 19

* Leaves mostly seattered or verticillate......................................................

Nos. 15, 16

§ Leaves broader, ovate, lanceolate, etc. Plants all native. (2)

2 Stems dividing above into branches, corymbed or panicled.......................

Nos. 13,14

2 Stems simple. - Leaves sessile, cordate-clasping at base........................

Nos. 11,12

2 Stems simple. - Leaves petiolate, the petioles often quite short. (3)

3 Flowers (small) with a white crown and purplish - white corolla..........

Nos. 8 - 10

3 Flowers with a white a crown and greenish - white corolla.................

Nos. 5 - 7

3 Flowers (large) with both crown and corolla purple-tinged. (4)

4 Follicles smoothish (as are all the foregoing)....

Nos. 3,4

4 Follicles sprinkled with soft warty spines.......

Nos. 1, 2

1 A. cornuti Decaisne. Simple, stout; lvs. oblong-ovate, short-acuminate, short-petiolate, downy beneath; pedicels shorter than the leaves, densely many-flowered; cor. lobes ovate reflexed, 4 times shorter than the pedicils; hoods of the crown ovate, obtuse, not longer than the uncinate horn. - A common, very milky herb, 3 to 4f high, in hedges and road-sides. Lvs. 5 to 8' by 2 to 3'; veinlets, as in most species, nearly at right angles to the midvein. Ped. stout, between the petioles, bearing a, globular umbel of a hundred greenish purple flowers, few of which prove fruitful. Pods full of seeds with their long silk. Jl

2 A. Sullivantii Engel. Tall, very smooth; lvs. ovate-oblong, erect, cordate, on very short petioles; hoods of the crown obovate, obtuse and entire at apex, obtusely auriculate without on each side at base; horns slender but obtuse; follicles with scattered, warty spines. - Near Columbus, Ohio (" Sullivant." Mr. A. II. Watson). Said to resemble A. cornuti in foliage and fruit, but remarkably different in its crown. Petals 4 to 5" long, greenish purple. Hoods twice as long as the anthers. Jl

3 A. purpurascens L. St. simple, erect, puberulent; lvs. elliptical, ovate-elliptical or ovate, mucronate, narrowed at base into a short- petiole, smooth above, tomentous-pubescent and paler beneath; ped. terminal, shorter than the leaves; hoods oblong or lance-ovate, obtuse, horns falcate, acute, abruptly bent to horizontal. - In hedges and thickets, N. H., Mass. to Wis. and Ky. St. 3f or more high, simple or slightly branched at top. Lvs. with the midvein purple. Cal. small, green. Cor. dark purple, with reflexed segments. Crown purple, twice as long as the antheridium, the points of its horns lying close upon it. Jl

4 A. rubra L. St simple, erect; lvs. ovate-acuminate, very acute, subcordate or rounded at base, on very short petioles, glabrous; umbels on long, mostly terminal peduncles; few-flowered; hoods of the crown acute, rather longer than the suberect horn. - A small and elegant species in Penn., N. J., and Car., not common. St. 1 to 2f high, with a pubescent line on one side. Lvs. 3 to 5' by 1 to 2', in remote pairs, the upper sometimes alternate. Ped. 1 to 5, 2 to 3' long, pedicels about 1'. Fls. purple, the crown red. Follicles ventricous-acuminate, smoothish. Jl, Aug. (A. laucifolia Mx. A. acuminata Ph.)

5 A. phytolaccoides Ph. Poke-leaved Silkweed. St. simple, erect, pube-rulent; lvs. broadly ovate, attenuated ai base and apex, acute, smoothish both sides, glaucous; ped. whitish puberulent, many-flowered; pedicels slender, loose, about as long as the peduncle; antheridium stipitate; hoods truncate, with 4 unequal teeth; horns subulate, exserted, suberect. - Tall and handsome, in low, shady grounds, Can. to Ga. and Ark. St. 4 to 5f high. Lvs. 6 to 9' by 2 to 4'. Umbels near the top on lateral peduncles 4 to 6' long, with about 20 large flowers on nodding pedicels near 2' long. Petals greenish, crown white, tinged with pink. June.