RUBIACEAE 1107 



styles united to the narrow stigmas. Ovules several in each cavity. Capsule partly 

 inferior, the top extending beyond the hypanthium, more or less distinctly 2-lobed, locu- 

 licidal above. Seeds rounded, few or several in each cavity, peltate, with a reticulated or 

 rough testa. Endosperm horny. Embryo clavate. BLUETS. 



Peduncles and pedicels solitary or nearly so, terminal or lateral. 



Flowers and fruits on straight upright, elongated peduncles or pedicels. 

 Perennial by slender creeping rootstocks. 



Plants erect : sepals lanceolate : corolla-tube glabrous within. 1. H. caerulea. 



Plants diffusely spreading : sepals oblong : corolla-tube pubescent within. 2. H. serpyllifolia. 

 Annual, sometimes winter annuals, with delicate roots. 



Sepals much surpassed by the corolla-tube. 3. H. minor. 



Sepals about equalling the corolla-tube. 4^Jf. minima. 



Flowers on short horizontal peduncles or pedicels which are recurved in fruit. 

 Annual plants. 



Corolla salverform : plant erect. 5. H. subviscosa. 



Corolla funnelform : plant depressed-spreading. 



Flowers peduncled : corolla 6 mm. long. 6. H. humifusa. 



Flowers sessile : corolla 3 mm. long. 7. H. Cro/tiae. 



Perennial plants. 8. H. rotundifolia. 



Peduncles and pedicels aggregated in effuse cymes. 

 Sepals fully as long as the hypanthium. 



Sepals conspicuously surpassing the capsule. 



Corolla less than twice as long as the sepals : sepals 4-8 mm. long. 9. H. lanceolata. . 



Corolla over twice as long as the sepals : Sepals 2-3 mm. long. 10. H. purpurea. 



Sepals slightly surpassing the capsule. 



Leaf-blades, especially those of basal leaves, conspicuously ciliate. 11. H. ciliolata. 



Leaf-blades perfectly glabrous, at least never ciliate. 



Corolla 8-9 mm. long : mature hypanthium and calyx 3.5-4 mm. long. 12. H. longifolia. 

 Corolla 4-5.5 mm. long : mature hypanthium and calyx 2.5-3 mm. long. 13. H. tenuifolia* 

 Sepals shorter than the hypanthium. 



Stems erect or ascending, sometimes diffusely branched at the base; the 



branches neither spreading nor prostrate. 

 Capsules much longer than broad, 2.5-3 mm. long. 



Capsules over 2 mm. thick : leaves of the branches linear. 14. H. angustifolia. 



Capsules less than 2 mm. thick : leaves of the branches filiform. 15. H. tennis. 



Capsules fully as broad as long, 1-1.5 mm. long. 16. H. fllifolia. 



Stems branched' at the base, the branches prostrate or spreading. 



Sepals as long as the hypanthium, at least during anthesis: Floridian 



species. 17. H. pulvinata. 



Sepals shorter than the hypanthium, at least during anthesis : Texan 



species. 18. H. salina. 



1. Houstonia caeiulea L. Perennial, glabrous. Stems erect, often tufted, 2-15 cm. 

 tall, branching, or sometimes simple : leaves mainly basal ; blades oval, ovate or spatulate, 

 2-5 mm. long, as long as the petiole or longer, obtuse : peduncles slender, 2-7 cm. long : 

 hypanthium becoming 2 mm. high : sepals lanceolate, longer than the hypanthium : 

 corolla lilac, blue or white, with a yellow eye ; lobes oval, acute, 5-7 mm. long, as long as 

 the tube or shorter : capsules broader than high, 3-4 mm. broad. 



In meadows and on banks, Nova Scotia to Quebec and Michigan, Georgia and Alabama. Spring 

 and early summer. INNOCENCE. 



2. Houstonia serpyllifolia Michx. Perennial, glabrous. Stems spreading and 

 creeping, 3-30 cm. long, more or less branched and matted : leaves numerous ; blades 

 ovate, oval or suborbicular, 1-6 mm. long, mostly obtuse, as long as the petioles or longer : 

 peduncles nearly filiform, 2-8 cm. long, simple or branched : hypanthium becoming 2 mm. 

 long : sepals oblong, sometimes narrowly oblong, longer than the hypanthium : corolla 

 usually deep blue, 9-12 mm. broad ; lobes oval, acute, as long as the tube or longer : 

 capsules 3-3.5 mm. broad. 



On mountain tops and slopes, Virginia and West Virginia to Georgia. Spring and summer. 



3. Houstonia minor (Michx.) Britton. Annual, nearly glabrous, or rarely puber- 

 ulent. Stems erect, 1-10 cm. tall, simple or branched : leaves mainly basal ; blades oval, 

 elliptic or ovate, acute, 2-10 mm. long, ciliate, usually acute ; petioles as long as the blades 

 or shorter : pedicels slender, often 1-3 cm. long : hypanthium becoming 1.5-2 mm. high : 

 sepals oblong or linear-oblong, longer than the hypanthium : corolla deep blue ; tube 3-4 

 mm. long, about twice as long as the sepals ; lobes oblong or oval, acute, 3-5 mm. long : 

 capsules 3-4 mm. broad, notched at the apex. [H. patens Ell.] 



In dry sandy soil, Virginia and Arkansas to Florida and Texas. Spring. An apparently depau- 

 perate state, with narrow leaf- blades, isH. minor pusllla (A. Gray) Small, [H. patens var. pusitta A. Gray]; 

 it occurs in the Gulf States. 



4. Houstonia minima Beck. Annual, glabrous or rough-pubescent. Stems branched 

 at the base, the branches diffuse, 1-10 cm. long, more or less forking: leaves mainly 

 basal ; blades spatulate to obovate or ovate, 2-8 mm. long, acute, ciliate ; petioles shorter 

 than the blades : pedicels 1-1.5 cm. long : hypanthium becoming 1-1.5 mm. high : sepals 

 oblong-lanceolate, much longer than the ovary : corolla lilac or bluish ; tube about as long 



