708 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 

 7. IPOMOEA. 15 Morning-glory 



Plants herbaceous, annual or perennial; stems erect, trailing, or 

 twining; leaves with entire to pedately parted blades; flowers solitary 

 or in few-flowered clusters; outer sepals commonly larger than the 

 inner ones; corolla mostly funnelform, sometimes salverform, the 

 limb entire or very shallowly lobed; capsule globose, 2- to 4-valved; 

 seeds commonly 4. 



Several species of this large genus are favorite ornamentals, culti- 

 vated under the names morning-glory, cypressvine, etc. 



Key to the species 



1. Corolla bright red, salverform, or the elongate tube narrowly funnelform, 

 the limb not more and usually less than 15 mm. in diameter; plant glabrous 



or nearly so; stems twining 1. I. coccinea. 



1. Corolla pink, purple, blue, or white (2). 



2. Leaf blades entire, obtuse or short-cuneate at base, linear to oblong-lanceo- 

 late, often 10 cm. long or longer, 6 or more times as long as wide; plant 

 perennial, glabrous; stems stout, prostrate except near the base, not at 

 all twining; sepals broad, very obtuse, scarious-margined; corolla white 

 with a pink throat, broadly funnelform, 6 to 10 cm. long. 



2. I. LONGIFOLIA. 



2. Leaf blades variously toothed or lobed or, if entire, then cordate at base, 



much less than 6 times as long as wide (3). 



3. Plants perennial with a tuberous-thickened root, glabrous or nearly so; 



stems not twining or very weakly so (4). 



4. Sepals setaceous-caudate; corolla 5 to 8 cm. long, the tube elongate, 



narrow, rather abruptly expanded into the throat; tuber elongate; 



leaf blades usually sparsely strigose, deeply sagittate to pedately 



lobed, the lobes divergent, lanceolate, linear, or oblong; calyx not 



warty or very obscurely so at base 3. I. thurberi. 



4. Sepals not setaceous-caudate; corolla not more than 5 cm. long, the tube 

 gradually expanded into the throat; leaf blades glabrous (5). 

 5. Leaf blades laciniate-dentate at the broad apex, otherwise entire, 

 obovate-cuneate; tuber globose or nearly so; petioles less than 



5 mm. long; calyx conspicuously warty 4. I. egregia. 



5. Leaf blades pedately parted or divided, the segments elongate, nar- 

 rowly linear or filiform, not more than 2 mm. wide (6) . 

 6. Sepals not or not conspicuously warty; petioles 10 to 20 mm. long; 



corolla 4 to 5 cm. long; tuber elongate 5. I. lemmoni. 



6. Sepals conspicuously warty; petioles seldom more than 5 mm. long; 

 corolla not more than 3 cm. long (7). 

 7. Tuber elongate; sepals 5 to 6 mm. long; peduncle and pedicel 

 together usually not much longer than the calyx. 



6. I. MTTRICATA. 



7. Tuber usually globose or nearly so; sepals 7 to 9 mm. long; 

 peduncle and pedicel considerably longer than the calyx, 



often twice as long 7. I. plummerae. 



3. Plants annual or, if perennial, then the root not tuberous-thickened (8). 

 8. Leaf blades pedately 5- to 9-parted or divided, the lobes linear or almost 

 filiform, the midlobe rarely more than 4 mm. wide; sepals con- 

 spicuously scarious-margined (9). 

 9. Corolla 5 to 8 cm. long, trumpet-shaped, with a long, narrow tube; 

 plant entirely glabrous; stems twining; calyx and pedicel often 



sparsely verrucose 8. I. tenuiloba. 



9. Corolla not more than 4 cm. long; plants sparsely and inconspicuously 



hirsute, or glabrate; stems erect to procumbent, sometimes feebly 



twining at apex (10). 



10. Calyx and pedicel glabrous; sepals often crested or warty on the 



midrib, 3 to 7 mm. long; corolla with the tube and throat not 



more than 10 mm. long, the limb less than 10 mm. in diameter. 



9. I. COSTELLATA. 



1 5 Reference: House, H. D. the north American species of the genus ipomoea. N. Y. Acad. Sci. 

 Ann. 18: 181-263. 1908. 



