26 NORTH AMERICAN FLORA [VOLUME 32 
1. Houstonia procumbens (Walt.) Standley. 
Anonymos procumbens Walt. Fl. Car. 86. 1788. 
Poiretia procumbens J. F. Gmel. Syst. 2: 263. 1791. 
Houstonia rotundifolia Michx. Fl. Bor. Am. 1: 85. 1803. 
Anotis rotundifolia DC. Prodr. 4: 433. 1830. 
Hedyotis veronicaefolia Steud. Nom. ed. 2. 1: 729. 1840. 
Hedyotis rotundifolia T. & G. Fl. N. Am. 2: 38. 1841. 
Oldenlandia rotundifolia A. Gray; Chapm. FI. S. U. S. 180. 1860. 
Prostrate perennial, with filiform rootstocks or with long slender stems rooting at the 
nodes, copiously branched, the branches quadrangular, hirsutulous or glabrous, the internodes 
short or elongate; stipules minute, ciliate or naked; petioles 4 mm. long or shorter, usually 
hirsutulous; leaf-blades mostly suborbicular, sometimes oval or obovate, 5-15 mm. long, 
2.5-15 mm. wide, broadly rounded at the apex or sometimes acutish, usually rounded at the 
base but sometimes cuneate, thin, bright-green above and hirsutulous or glabrous, paler 
beneath and glabrous, 1-nerved, the margins plane or revolute, ciliate; flowers axillary, solitary, 
the pedicels slender, 16 mm. long or shorter, recurved in fruit, the plants in summer often 
producing fertile apetalous flowers; hypanthium about 1 mm. long, glabrous or hirsutulous; 
calyx-lobes as long, ovate-oblong, acutish; corolla salverform, 9-15 mm. long, white, the tube 
slender, ampliate above, the lobes ovate or oblong, acute, shorter than the tube, the throat 
hirsutulous; capsule subdidymous, 4-5 mm. broad, almost half inferior, hirsutulous or glabrous; 
seeds crateriform, rounded, 1-1.5 mm. broad, black, rough-scrobiculate. 
TYPE LOCALITY: Carolina. : ‘ ; nh 
DISTRIBUTION: In low, sandy soil, South Carolina to Florida and Louisiana. 
2. Houstonia rubra Cav. Ic. 5: 48. 1799. 
Hedyotis rubra A. Gray, Mem. Am. Acad. II. 4: 61. 1849. 
Oldenlandia rubra A. Gray, Pl. Wright. 2: 68. 1853. 
Houstonia saxicola Eastw. Proc. Calif. Acad. II. 6: 291. 1896. 
Densely cespitose perennial, 4-7 cm. high, from a long slender taproot, much branched 
below, the stems stout, scaberulous or glabrous, minutely papillose, densely leafy, the inter- 
nodes very short; stipules minute, with a few short glanduliferous setae; leaves sessile, the 
lowest oblanceolate-linear, the upper linear, 5-25 mm. long, about 1 mm. wide, mucronate, 
thick, minutely scaberulous and papillose or glabrous, the margins more or less revolute; 
flowers axillary, solitary, short-pedicellate, the pedicels recurved in fruit; hypanthium very 
short, glabrous, minutely papillose; calyx-lobes linear-subulate, about 2 mm. long, somewhat 
elongate in fruit; corolla purple, rarely white, salverform, 1.5-3 cm. long, the tube slender, 
ampliate above, glabrous outside, the 4 lobes lance-oblong, 5-8 mm. long, acute, minutely 
papillose within; anthers 2 mm. long; capsule depressed-globose, subdidymous, 3-5 mm. 
broad, two thirds superior, minutely papillose; seeds cymbiform, 1-1.5 mm. long, black, 
scrobiculate. 
TYPE LOCALITY: Ixmiquilpan, Hidalgo. 
DISTRIBUTION: Dry hillsides, southeastern Utah, Arizona, and New Mexico to Puebla. 
ILLUSTRATION: Cav. Ic. pl. 474, f. 1. 
3. Houstonia Wrightii A. Gray, Proc. Am. Acad. 17: 202. 1882. 
Hedyotis humifusa A. Gray, Pl. Wright. 1: 82, in part. 1852. Not H. humifusa A, Gray, 1850. 
Oldenlandia humifusa A. Gray, Pl. Wright. 2: 68,in part. 1853. 
Cespitose perennial, erect or spreading, 5-20 cm. high, the stems numerous, stout or 
slender, mostly simple below and branched above, the branches quadrangular, scaberulous or 
minutely papillose, the internodes usually shorter than the leaves; stipules often conspicuous, 
2.5 mm. long or shorter, white, obtuse or subtruncate, entire or minutely denticulate; leaves 
opposite, sessile, linear, oblong-linear, or the lowest narrowly spatulate, 6-25 mm. long, 0.6—4 
mm. wide, acute or obtuse at the apex, thick, glabrous, 1-nerved, the margins often revolute; 
flowers axillary, usually in terminal cymose inflorescences, short-pedicellate, the pedicels 
recurved after anthesis; hypanthium glabrous, papillose; calyx-lobes lance-linear, 1.5—2 mm. 
long, acute; corolla salverform, purplish, 2.5-—4 mm. long, glabrous outside, the tube short 
and thick, the lobes oblong or ovate-oblong, acute or obtuse, equaling or only half as long as 
