228 ASCLEPIADACEAE. 



converging around the stigma or slightly adhering to it, not accompanied 

 by a crown. Gynoecium of 2 carpels, the styles and stigmas, and sometimes 

 the carpel-bodies, united : two carpels usually maturing. 



Anthers imfippendaged at the base, not connected with the stigma : corolla-lobes 

 sinistrorsely convolute: flowers axillary to leaf like bracts. 1. Vinca. 



Anthers appendaged at the base, converging around the stigma 

 and partially adherent to it : corolla-lobes dextrorsely convolute : 

 flowers in terminal cymes. 2. Apocynum. 



1. VINCA L. Trailing or creeping herbs. Leaves opposite. •Corolla- 

 tube dilated at the mouth. 



1. V. minor L. Stems 2-7 dm. long: leaf -blades ovate to oblong, 1.5-4 cm. 

 long: calyx-lobes lanceolate to subulate-lanceolate, 3-3.5 mm. long: corolla 

 blue; tube 9-10 mm. long; lobes undulate-truncate.- — Eather common, on 

 banks near dwellings. Nat. of Eu. — Spr. — Periwinkle. Myrtle. 



2. APOCYNUM [Tourn.] L. Upright herbs. Leaves opposite: blades 

 relatively broad. Corolla campanulate to ureeolate, with entire appendages 

 near the base, the lobes erect or recurved, narrow. — Sum. — Dogbane. 

 Indian-hemp. 



Corolla pink, 5-9 mm. long : lobes revolute : stamens nearly as long as the coroUa- 

 tul3e. 1. A. (indrosdcviifoHum. 



Corolla white or greenish, 2.5-4 mm. long : lobes erect or 

 nearly so : stamens much shorter than the corolla- 

 tube. 

 Leaf-blades narrowed at the base, distinctly petioled. 

 Corolla greenish, 3.5-4 mm. long ; follicles 12-20 



cm. long. 2. A. canuahininn. 



Corolla white, 2.5-3 mm. long : follicles 6-9 cm. 



long. 3. A. album. 



Leaf-blades, at least those of the stem-leaves, with 



broad cordate-clasping bases, sessile. 4. A. siMricum. 



1. A. androsaemifolium L. Plants 3-15 dm. tall: leaf -blades ovate, oljlong, or 

 oval, 4-11 cm. long: cymes rather long: calyx-lobes ovate to ovate-lanceolate, 

 2-2.5 mm. long: corolla-lobes nearly as long as the tube: follicles 10-17 em. 

 long. — Common, in thickets. 



2. A. cannabinum L. Plants 8-18 dm. tall: leaf -blades oblong to oblong-ovate 

 or oblong-lanceolate, 5-12 cm. long: cymes rather dense: calyx-lobes lanceo- 

 late, 2.5-3 mm. long: corolla-lobes about half as long as the tube: follicles 12- 

 20 cm. long. — Common, in thickets. 



3. A. album Greene. Stems 3-9 dm. tall, with spreading often glaucous 

 branches: leaf -blades oblong, elliptic, or ovate-oblong, 2.5-8 cm. long, acute at 

 both ends, or rounded at the base, short-i^etioled : cymes rather lax: calyx- 

 lobes lanceolate, 2-2.5 mm. long, acuminate : corolla white or whitish, 3-4 mm. 

 long ; lobes ovate, erect or nearly so : follicles 6-9 cm. long. — Susquehanna 

 valley. Frequent, in rocky places. 



4. A. siblricum Jacq. Stems 3-8 dm. tall, with ascending usually glaucous 

 branches: leaf -blades ovate, ovate-lanceolate, or oblong, 3-9 cm. long, abruptly 

 pointed, those of the cauline leaves subeordate or cordate at the base, sessile 

 or nearly so: cymes rather dense: calyx-lobes linear-lanceolate or subulate. 

 2.5-3.5 mm. long, acuminate: corolla greenish- white, 3-4 mm. long; lobes ovate, 

 erect or nearly so: follicles 11-14 cm. long. — Susquehanna valley. Rather 

 common, in rocky places. 



Family 2. ASCLEPIADACEAE. Milkweed Family. 



Perennial herbaceous or woody plants, with usually umbel-like cymes. 

 Androecium of usually 5 stamens, with the anthers more adherent to the 



