236 DICOTYLEDONOUS PLANTS. 



Umbels terminal, on short peduncles. Flowers dark purple, about 

 the size of A. syriaca. Well defined by the peculiar curvature 

 of the horn. 



7. A. obtusifolia Mich. : stem simple, erect ; leaves closely sessile or 

 clasping, oblong-obtuse, undulate on the margin, very smooth, glauc- 

 ous beneath ; umbel terminal, long peduncled, generally solitary ; nec- 

 tary slightly 2-toothed ; horns exserted. A. purpurascens Walt. 



HAB. Sandy fields. N. Y. to Car. June. U.Stcm 23 feet 

 high, erect, simple, very smooth. Umbels 1 3, terminal, on 

 long peduncles. Leaves much waved on the margin. Flmcers 

 large, pale purple. 



8. A. varicgala Linn. : stem simple, erect ; leaves ovate, petiolate, 

 smooth, somewhat glaucous beneath ; umbels lateral and terminal, on 

 short peduncles, crowded ; pedicels tomentose ; horn broad-falcate. 

 A. hyltrida Mich. 



HAB. Woods. N. Y. to Car. July, Aug. If . Stem 34 feet 

 high, pubescent above. Leaves slightly acuminate, on pubescent 

 petioles. Umbels 2 C, densely flowered. Flowers white. 



9. A. acuminata Pursh : stem erect, very smooth, simple ; leaves 

 ovate, subcordale, acuminate, subsessile ; umbels lateral, solitary, 

 erect ; nectary acute ; horns scarcely exserted. A. jjcriflocafulia Nutt. 

 A. cordatu H r alt. 



HAB. Sandy swamps. N. J. to Car. Aug. It. Root large 

 and tuberous; Stem 18 inches high. Leaves smooth on both 

 sides. Umbels about 2, dense. Flowers purple and green. 



10. A. laurtfolia Mich. : stem erect, smooth ; leaves nearly sessile, 

 oval-lanceolate, tapering at the summit, very acute, smooth, margins 

 somewhat rough ; umbels on long peduncles, terminal and axillary. 



HAB. Penn. MuJd. Aug. U- Stem 2 feet high, pubescent 

 near the top. l^eaxes sessile, obtuse at base. Umbels few, near 

 the summit. Carol 3 or 4 times as the long as calyx, green and 

 purple. 



11. A. quadrifolia Jacq. : stem erect, simple, smooth ; leaves in 

 fours, ovate, acuminate, membranaceous, petiolate, smooth ; umbels 

 2, terminal, erect, loose ; pedicels capillary ; nectary 2-toothed ; horn 

 very short. (< 9 



HAB. Stony woods. Can. to Car. W. to Miss. June. If. 

 Stem 1 2 feet high, slender, pubescent towards the top. Learcs 

 in fours ; the upper and lower ones often opposite. Umbels few, 

 on long peduncles. Floicers small, white. 



12. A. terticillata Linn. : stem simple, marked with pubescent lines ; 

 leaves mostly whorled, narrow-linear, revolute ; nectaries short, biden- 

 tate ; horns falcate, much exserted. 



HAB. Dry hills. N. Y. to Car. W. to Miss. June, July. If. 

 Stem 3 feet high, very slender. Leaves generally in whorls of 

 5 or 6, 2 3 inches long, very narrow. Umbels numerous. Floic- 

 crs small, yellowish-white. 



