32 NORTH AMERICAN FLORA [VOLUME 32 
thium less than 1 mm. long, glabrous; calyx-lobes oblong-lanceolate, acute, at anthesis longer 
than the hypanthium, fleshy, in fruit equaling or slightly exceeding the capsule; corolla salver- 
form, pink, 10-15 mm. long, glabrous outside, often withering-persistent, the lobes oblong or 
ovate-oblong, obtuse or acutish, usually less than one third as long as the tube, glabrous within; 
capsule subglobose, 1.5-2.5 mm. in diameter, two thirds inferior, rounded at the apex; seeds 
oblong, peltate, concavo-convex, black, minutely scrobiculate. 
TYPE LOCALITY: In a canyon near Santa Rosalia, Lower California. 
DISTRIBUTION: Southern Lower California and the adjacent islands. 
20. Houstonia mucronata (Benth.) B. L. Robinson, Proc. Am. Acad. 
45: 401. 1910. 
Hedyotis mucronata Benth. Bot. Voy. Sulph. 19. 1844. 
Houstonia fruticosa Rose, Contr. U. S. Nat. Herb. 1: 132. 1892. 
Erect glabrous shrub, 2-6 dm. high, fruticose nearly throughout, much branefted: the 
branches erect or ascending, stout, glabrous, the bark grayish-yellow, the internodes usually 
very stout; stipules about 1 mmi. long, the lobes short-triangular, glandular-setiferous; leaves 
opposite, usually with dense fascicles of leaves in the axils, sessile, linear or semiterete, 3-18 mm. 
long, 1 mm. wide or narrower, acute, mucronulate; flowers in small few-flowered terminal cymes, 
on pedicels 1 cm. long or shorter, often nearly sessile; hypanthium about 1 mm. long; calyx- 
lobes longer than the hypanthium, lance-oblong, acute or acuminate, very thick, with a stipitate 
gland in each sinus, in fruit equaling or shorter than the capsule; corolla 10-12 mm. long, 
salverform, white, the tube slender, the lobes about 3 mm. long, oblong-ovate, acutish; capsule 
subglobose, 2—2.5 mm. long, two thirds or three fourths inferior, rounded or truncate at the 
apex; seeds 0.5—0.8 mm. long, oblong, peltate, concavo-convex, dark-brown, minutely scrobicu- 
late. 
TYPE LOCALITY: Magdalena Bay, Lower California. 
DISTRIBUTION: Southern Lower California and on the adjacent islands. 
ILLUSTRATION: Benth, Bot. Voy. Sulph. pl. 13. 
21. Houstonia peninsularis Brand. Zoe 5: 160. 1903. 
Erect shrub, 1-3 dm. high, sparsely branched, fruticose below, the branches nearly terete, 
yellowish-brown, very densely hirtellous, the internodes shorter than the leaves; stipules very 
short, closely glandular-setiferous; leaves opposite or 3- or 4-verticillate, sessile, linear, 1-4 cm. 
long, 1.5 mm. wide or narrower, attenuate at the apex, densely hirtellous, the margins sub- 
revolute; flowers in small dense pedunculate terminal cymes, on pedicels 4 mm. long or shorter, 
often sessile; hypanthium about 1 mm. long, densely hirtellous; calyx-lobes subulate, attenuate, 
longer than the hypanthium, in fruit equaling or shorter than the capsule; corolla purple, salver- 
form, about 15 mm. long, the tube very slender, hirtellous, the 4 lobes ovate-oblong, acute or 
obtuse, about one third as long as the tube, minutely papillose within; capsule subglobose, 
2-2.5 mm. long, almost wholly inferior, rounded at the apex, densely hirtellous; seeds concavo- 
convex, minutely scrobiculate. 
TYPE LOCALITY: On nearly perpendicular bluffs, Sierra de la Trinidad, Lower California. 
DISTRIBUTION: Vicinity of the type locality. 
22. Houstonia acerosa A. Gray; Benth. & Hook. Gen. 2: 60. 1873. 
Hedyotis acerosa A. Gray, Pl. Wright. 1: 81. 1852. 
Oldenlandia acerosa A. Gray, Pl. Wright. 2: 67. 1853. 
Mallostoma acerosum Hemsl. Biol. Centr. Am. Bot. 2: 31. 1881. 
Ereicoctis acerosa Kuntze, Rev. Gen. 281. 1891. 
Erect or ascending cespitose shrub, 0.5—3 dm. high, fruticose nearly throughout, the stems 
usually numerous, simple or sparsely branched above, angulate and striate, scaberulous or 
minutely hirtellous, the internodes usually much shorter thar the leaves; stipules 1 mm. long 
or shorter, whitish, setuliferous or cuspidate; leaves mostly 3-'or 4-verticillate, sessile, 5-12 mm. 
long, rigid-setaceous or acerose-linear, scaberulous or hirtellous or glabrate, suberect; flowers 
axillary or terminal, sessile or rarely very short-pedicellate; hypanthium scaberulous, short; 
calyx-lobes setaceous, 3-6 mm. long, scaberulous or hirtellous, in fruit usually longer than the 
