232 iVSCLEPIADACE^. 



3. A. hypericifolium Ait. : leaves oblong, smooth, on very short petioles, 

 mucronate, obtuse and subcordate at base ; cymes shorter than the leaves ; 

 calyx nearly as long as the tube of the corolla. 



Gravelly banks of 'streams. Can. to Virg. W. to Miss. June, July. %. — 

 Stem 2 feet high, erect. Leaves on very short petioles. Flowers greenish-white, * 

 in terminal and lateral cymes. Plant smaller than the preceding. 



Hypericum-leaved Dog's Bane. 



4. A. pubesccns R. Brown : leaves on short petioles, ovate-oblong, mu- 

 cronate, hoary-pubescent beneath ; cymes short, pubescent ; corolla longer 

 than the calyx. A. cannabinum Mich. 



Fields. Can. to Car. July, Aug. 'Zl-. — Stem 2 — 3 feet high. Flowers small, 

 greenish- white. Jt is perhaps nothing more than a variety of A. cannabinum. 



Pubescent Dog's Bane. 



Order LXXIX. ASCLEPIADACEJE.— Milkweeds. 



Calyx 5-divided, persistent. Corolla 5-lobed, regular, decidu- 

 ous ; aestivation imbricate, rarely valvate. Stamens 5, inserted 

 into the base of the corolla ; filaments usually connate ; anthers 

 2-celled or incompletely 4-celled; pollen, when the anther 

 bursts, coalescing into masses which are- as numerous as the 

 cells*, or sometimes confluent by pairs, and sticking to the 5 

 processes of the stigma. Ovaries 2 ; styles 2, close to each 

 other ; stigma 1, common to both styles, 5-comered. Follicles 

 2, 1 of which is sometimes abortive. Seeds numerous, comose, 

 with thin albumen. — Shrubs or herbaceous plants, almost al- 

 ways milky and often twining. Leaves entire, having ciliee be- 

 tween their petioles instead of stipules. Flowers somewhat 

 umbelled, fascicled or racemose, proceeding from between the 

 petioles. 



1. ASCLEPIAS. Z.m7i.— Milkweed. Silkweed. 

 (The Greek name of JEsculapius ; to whom this genus is dedicated.) 

 Calyx small, 5-parted ; segments lanceolate. Corolla 5-part- 

 ed ; the lobes lanceolate, reflexed. Stamineal crown (nectary) 

 5 -leaved ; leafets opposite the anthers, each mostly producing 

 from its base a subulate averted process or little horn. Pollen- 

 masses 5 distinct pairs, compressed, affixed by their attenuated 

 summits in the cells of the anthers. Stigma depressed. Folli- 

 cles ventricose, smooth or muricate. Seeds comose. 



* Nectary or Stamineal crown with horns. 

 f Follicles muricate. 

 1. A. Syriaca Linn: stem sub-simple, smoothish; leaves oblong-lanceo- 



