ParT 1, 1918] RUBIACEAE 37 
32. Houstonia longifolia Gaertn. Fruct. 1: 226. 1788. 
Houstonia obtusifolia Raf. Ann. Gén. Sci. Phys. 5: 226. 1820. 
?Houstonia oblongifolia Raf. Ann. Gén. Sci. Phys. 5: 226. 1820. 
?Houstonia heterophylla Raf. Ann. Gén. Sci. Phys. 5: 227. 1820. 
Anotis longifolia G. Don, Gen. Hist. 3: 535. 1834. 
Hedyotis longifolia Hook. Fl. Bor. Am. 1: 286. 1834. 
Oldenlandia purpurea longifolia A. Gray, Man. ed. 2. 173. 1856. 
Houstonia purpurea longifolia A. Gray, Man. ed. 5. 212. 1868. 
Erect perennial, 1-3 dm. high, the stems few or numerous, simple or sparsely branched, 
stout or slender, angulate, commonly puberulent or hirsutulous below, sometimes glabrous, 
glabrous above, the internodes usually elongate; stipules scarious, 3 mm. long or shorter, acute 
or rounded, often dentate; basal leaves usually wanting at anthesis but sometimes present and 
forming large tufts, petiolate, the blades elliptic or oblanceolate, 1-3 cm. long, 2-5 mm. wide, 
obtuse or acute at the apex, acute or attenuate at the base, glabrous or slightly scaberulous on 
the upper surface, paler and glabrous beneath, 1-nerved; cauline leaves sessile or nearly so, 
linear, linear-oblanceolate, or narrowly oblong, 1.5—5 cm. long, 8 mm. wide or narrower, obtuse 
to attenuate at the apex and base, glabrous, or scaberulous on the margins, 1-nerved; flowers 
numerous, in lax or usually dense, small cymes, the pedicels slender, 8 mm. long or shorter; 
hypanthium at anthesis about 1 mm. long, glabrous; calyx-lobes lance-linear, attenuate, about 
twice as long as the hypanthium, in fruit equaling or usually much exceeding the capsule; corolla 
funnelform, 7-8 mm. long, purple or purplish, glabrous outside, the lobes ovate-oblong, ob- 
tuse or acute, more or less white-villous within, about half as long as the tube; anthers 
exserted; capsule subglobose, 2.5—3 mm. long and nearly as wide, slightly compressed, half 
inferior, rounded or retuse at the apex, the free portion glabrous; seeds concavo-convex, 
oblong or oval, 1 mm. long or smaller, scrobiculate, black. 
TYPE Locality: Not stated. 
DISTRIBUTION: In dry soil, Maine to Saskatchewan, Missouri, Mississippi, and Georgia. 
ILLUSTRATIONS: Gaertn. Fruct. pl. 49, f. 8; Britt. & Brown, Ill. Fl. f. 3399; ed. 2. f. 3919; Rob. 
& Fern. Man. f. 915; Torr. Fl. N. Y. pl. 44; Lam. Tab. Encye. pl. 79. 
33. Houstonia longipes S. Wats. Proc. Am. Acad. 18: 97. 1883. 
Erect perennial, 1-2.5 dm. high, the stems few, much branched above, the branches very 
slender, ascending or spreading, angulate, scaberulo-puberulent or glabrous; stipules 1 mm. 
long or shorter, rather firm, cuspidate, denticulate or laciniate; leaves sessile, filiform, or the 
lowest spatulate-linear, 12 mm. long or shorter, obtuse, thick, scaberulous or glabrous on the 
upper surface, glabrous beneath, the margins revolute; flowers few, in lax cymes, the pedicels 
stout, 3-12 mm long, ascending or divaricate; hypanthium at anthesis less than 1 mm. long, 
glabrous, the calyx-lobes oblong-lanceolate, acute, equaling or longer than the hypan- 
thium, scaberulo-ciliolate, in fruit equaling or slightly exceeding the capsule; corolla slender- 
funnelform, 7-8 mm. long, yellowish-white, glabrous outside, the lobes oblong, obtuse, densely 
white-villous within, nearly as long as the tube; anthers included; capsule subglobose, 1.5—2 
mm. long and somewhat broader, subcompressed, half inferior, rounded or slightly retuse at 
the apex, the free portion scabrous; seeds concavo-convex or subcrateriform, oval, about 1 mm. 
long, scrobiculate, black. 
TYPE LOCALITY: Mountains northeast of Monclova, Coahuila. 
DISTRIBUTION: Coahuila, Nuevo Leén, and San Luis Potosi. 
34. Houstonia rupicola Greenman, Proc. Am. Acad. 32: 286. 1897. 
Hedyotis stenophylla parviflora [no. 1] A. Gray, Pl. Wright. 1: 81. 1852. 
Houstonia fasciculata A. Gray, Syn. Fl. N. Am. 12: 27, in part. 1884. 
Erect perennial, from a woody base, the stems numerous, 4-14 cm. high, simple or branched, 
the branches stout, rigid, conspicuously angulate, scaberulous or glabrate; stipules minute, 
triangular, rigid, long-cuspidate, white-setiferous; leaves sessile, linear to narrowly oblong or 
elliptic-oblong, 3-15 mm. long, 2.5 mm. wide or narrower, acute, mucronate, pungent, thick and 
rigid, glabrous, lustrous on the upper surface, the margins ciliolate, the costa prominent be- 
neath; flowers in small, dense, terminal and axillary cymes, the pedicels stout, less than 1 mm. 
long; hypanthium at anthesis less than 1 mm. long, glabrous; calyx-lobes triangular-ovate, 
equaling or sharter than the hypanthium, acute or obtuse, ciliolate, in fruit equaling the cap- 
