DICOTrLBDONOUS PLANTS 213 



family, of which many of the important species, for instance, 

 the coffee shrub and the cinchona tree, are natives of warm or 

 tropical climates. 



I. HOUSTONIA, L. 



Annual, biennial, or perennial herbs ; stems erect or diffuse. 

 Leaves entire, stipules often only a line connecting the bases 

 of opposite leaves. Mowers small, solitary, or clustered. 

 Calyx 4-toothed, persistent. Corolla wheel-shaped to funnel- 

 form, 4-lobed. Stamens 4. Ovary 2-celled, style slender, 

 stigmas 2. Fruit a 2-celled, few-many-seeded capsule, open- 

 ing at the apex, free from the calyx.* 



1. H. ccerulea, L. Bluets, Innocence, Quaker Ladies, Ete- 

 BRIGHT. Perennial, from very slender rootstocks; stems tufted, 

 erect, smooth, forking, 3-6 in. high. Leaves sessile, often hairy- 

 fringed, the lower spatulate, the upper lanceolate. Flowers solitary, 

 on slender axillary peduncles. Calyx small. Corolla salver-form, 

 blue or white, yellow in the throat, smooth, of two forms, the stamens 

 projecting and the style short in one form, while in the other the 

 stamens are short and the style projecting. Capsule laterally com- 

 pressed, 2-lobed, shorter than the calyx. Common on open ground.* 



2. H. patens. Ell. Small Bluets. Annual. Stem erect, branched 

 at the base, forking above,- smooth, 2—4 in. high. Lower leaves oval 

 to ovate, petioled, the upper narrower and sessile. Flowers solitary, 

 on slender, axillary peduncles, blue or white. Calyx small. Lobes 

 of the corolla about as long as the tube ; stamens and style project- 

 ing or included. Capsule compressed, as long as the calyx. Com- 

 mon on dry, open ground.* 



3. H. purpurea, L. Large Bluets. Perennial ; stem stout, erect, 

 simple or branched, smooth or downy, 4-angled, 6-12 in. high. 

 Leaves ovate to ovate-lanceolate, sessile or short-petioled, 3-5-nerved, 

 often hairy-fringed on the margins. Flowers in terminal cymes, 

 purple to nearly white. Corolla funnel-form; the tube longer than 

 the limb, hairy within. Stamens and style projecting or included. 

 Capsule compressed-globose, much shorter than the calyx. In dry, 

 open woods.* 



Var. longifolia. Gray. Long-leaved Bluets. Perennial. Stem 

 erect, branched, smooth, 4-angled, 8-12 in. high. Leaves sessile, 

 the lower oblanceolate or spatulate, the upper linear, 1-nerved. 

 Corymbs terminal, few-flowered. Corolla light purple to white, the 

 lobes much shorter than the tube. Capsule compressed-globose, 

 nearly as long as the calyx. In dry, open woods.* 



