MONOPETALOUS EXOGENOUS PLANTS. 441 



lobes of the corolla, and inserted on its tube; anthers 

 2-celled; omr^ single, with numerous anatropous ovules; 

 stigmas 1-2 ; capsule 1-celled, or imperfectly 2-4-celled by 

 the introversion of the margins of the valves, septicidal- 

 ]y 2-valved; placentce parietal; seeds numerous; embryo 

 minute, in the axis of fleshy albumen. 



SYNOPSIS. 



♦ Corolla convolute, or (in Obolana) imbricated in the bud; testa membranaceom ; 



leaves sessile. 



Style conspicuoics, deciduous. Stigma linear. Corolla wlieel-shaped, 5-12-parted. 



S ABB ATI A. 



style persistent. Stigma roundish. Corolla tubular, A-b-parted Eustoma. 



Stigma sessile, flat persistent. Corolla bell or funnel-form, 4r-5-lobed, mostly with 



plaited appendages between the lobes Gentiana. 



Calyx and corolla i-lobed. Stigma sessile. Leaves sccUelike Bartonia. 



'2-leaved. Corolla i-lobed, imbri.cated in the bud Obolaria. 



Corolla wheel-shaiHd, 4-parted, (he lotes roith a large depressed gland in the middle. 



Frasera. 



** Corolla folded in the bud ; flowers clustered on thepetide. 

 Leaves floating, cordate. Flowers clustered on the patiole Limnanthemum. 



SABBATIA, Adans. American Centaury. 



Calyx 5-12-parted; corolla wheel-shaped, 5-12-parted, 

 withering-persistent ; stamens 5-12, inserted on the throat 

 of the corolla; anthers sagittate, mostly recurved; style 

 conspicuous; stigmas linear or oblong, twisted; capsule 

 globose, 1-celled, 2-valved, many-seeded. — Annual or bien- 

 nial branching herbs, with cymose or panicled white or 

 purple showy floiuers. 



* Calyx and corolla mostly ^parted. 



t Flowers in corymbose cymes, white, turning yellowish ; branches opposite. 



S. MACROPHYLLA, Hook. Glaucous ; stem terete, corym- 

 bosely branched above ; the branches opposite ; leaves thick, 

 erect, ovate-lanoeolate, acute, clasping, 3-5-nerved; cymes 

 large, flat-topped ; corolla small, the lobes thrice as long as 



19* 



