MONOPETALOUS EXOGENOUS PLANTS. 417 



tary, in the axils of the upper, mostly bract-like leaves, 

 rarely in lateral racemes ; corolla blue or white. 



* Floioers in tei^minal racerms. 



t Leaves cordate, ovate or oblong, crenaie, petioled ; the floral ones shorter than the 

 flowers, entire. 



S. PILOSA, Michx. Hairy; stem simple or sparingly 

 branched; leaves distant, ovate, obtuse, coarsely crenate, 

 the lowest rounded at the base, the upper ones abruptly 

 short-petioled, the floral ones spatulate, obtuse; racemes 

 short, few-flowered ; corolla pale blue. Dry sandy soil. July 

 and August. Stem l°-2° high ; leaves 1-2' long ; corolla 

 8"-9'' long. 



tt upper andflorcU leaves alike, entire, nearly sessile ; the lower broader, petioled, 

 and mostlij crenate. 



S. INTEGRIFOLI A, L. Piibescent throughout ; stem mostly 

 simple (6'-12' high) ; leaves small {^-V long), lanceolate, 

 obtuse, entire, tapering downward, sessile, the lowest ovate 

 or obovate, short-petioled, crenate or entire, the lower 

 floral ones sometimes longer than the flowers ; race7nes 

 leafy, few-many-flowered. Dry sandy soil. 



*♦ Flowers solitary, in the axils of the upper leaves. 



S. PARYULA, Michx. Stem low, pubescent ; leaves ovate 

 or roundish, obtuse, mostly entire, nearly sessile, strongly 

 veined ; floiuers small, peduncled ; fibers of the root often 

 bearing small tubers. Stem 6'-9' high ; leaves 4"-6" long ; 

 corolla blue, 2"-3" long. 



MACBRIDEA, Ell. 



Cah/x tubular-bell-shaped, 3-lobed, the upper lobe lan- 

 ceolate, entire, the two lower ones oblong, notched or en- 

 tire ; corolla inflated, 2-lipped, the upper lip arching, con- 

 cave, the lower broadly 3-lobed, spreading ; stamens 4, as- 

 cending under the upper lip ; filaments hairy ; anthers ap- 

 proximate by pairs, the cells diverging, hairy within, den- 



18* 



