Family 15. CROSSOSOMATACEAE 
By Joun KUNKEL SMALL 
Shrubs or small trees, with rough bitter bark. Leaves alternate, often 
approximate on short branches or clustered on spurs; blades simple, leathery, 
entire. Flowers perfect, solitary at the ends of short branches. Hypanthium 
turbinate. Calyx of 5 persistent sepals. Corolla of 5 white or purplish decid- 
uous petals. Androecium of many stamens, usually 15 or more; anthers ob- 
long to oval. Gynoecium of 3-5 stipitate ultimately distinct carpels borne in 
the base of the hypanthium. Ovary elongate; styles short, at least during 
anthesis, or obsolete ; stigmas depressed. Ovules several or many, borne in 2 
rows. Fruit acluster of 2-5 follicles. Seeds globular to reniform, each enclosed 
in a fimbriate aril. Endosperm thin, fleshy. 
1. CROSSOSOMA Nutt. Jour. Acad. Phila. II. 1: 150. 1848. 
Stems usually much-branched. Leaf-blades pinnately-veined, sessile or nearly so. 
Flowers pedicelled. Sepals very broad, usually suborbicular, concave. Petals spatulate to 
orbicular-obovate. Stamens usually borne in 2 rows. Carpels erect; style short or obso- 
lete ; stigma minute. Follicles spreading or recurved. Seeds orten adherent in a body by 
means of the aril-fringe. , 
Type species, Crossosoma californicum Nutt. 
Petals broadly obovate or orbicular-obovate ; follicles many-seeded. 1. C. californicum. 
Petals spatulate to oblong; follicles few-seeded. 
Follicle-body oblong-cylindric, wrinkled. 2. C. Bigelovii. 
Follicle-body ovoid, reticulate. 
Follicles stout-beaked, copiously glaucous ; leaf-blades mucronulate or 
sometimes obtuse. 3. C. glaucum. 
Follicles minutely beaked, not glaucous; leaf-blades mostly acute. 4. C. parvifiorum. 
1. Crossosoma californicum Nutt. Jour. Acad. Phila. II. 1: 150. 1848. 
Shrub or small tree, with a rough somewhat flaky bark ; leaf-blades oblong, oblong- 
obovate, spatulate or linear-spatulate, 2.5-9 cm long, commonly mucronate, sessile, or 
nearly so; flowers long-pedicelled ; hypanthium 4.5-5.5mm. broad at maturity ; sepals sub- 
orbicular, 8-12 mm. long ; petals white, broadly obovate to oblong-obovate, 14-18 mm. long; 
follicles drooping, 15-32 mm. long, the bodies cylindric, wrinkled, each terminating in a 
curved or hooked beak ; seeds about 3 mm. in diameter. 
TYPE LOCALITY: Santa Catalina Island, California. 
DISTRIBUTION : Santa Catalina and San Clemente Islands, California, and Guadalupe Island, 
Lower California. 
ILLUSTRATION: Pacif. R. R. Rep. 44: £2. 1, f- 7. 
2. Crossosoma Bigelovii S. Wats. Proc. Am. Acad. 11: 122. 1876. 
Shrub, with irregularly much-branched stems, often spinescent, the bark of the twigs 
light-gray or yellowish ; leaf-blades spatulate, cuneate, obovate or elliptic, or ovate to 
oblong-lanceolate on the twigs, 0.5-1.5 cm. long, acute or mucronulate, commonly gradually 
narrowed to the base; flowers short-pedicelled ; hypanthium 3-3.5 mm. wide at maturity ; 
sepals suborbicular, 4.5-5.5 mm. long; petals white or purplish, oblong to spatulate, 9-14 
mm. long; follicles 9-12 mm. long, the bodies oblong-cylindric, wrinkled, slender-stipitate, 
each terminating in'a short oblique beak; seeds about 2mm. in diameter. 
TYPE LOCALITY: Near the mouth of Bill Williams River, Arizona. ; 
DISTRIBUTION : Southeastern California, Arizona, and Lower California. 
ILLUSTRATION: Pacif. R. R. Rep. 4: p/. 1, excluding / 7 and dissections. 
VOLUME 22, Parr 3, 1908] 231 
