BUCKTHORN FAMILY 79 



42. Ceanothus prostratus Benth. Mahala-mats. Fig. 3152. 



Ceanothus prostratus Benth. PI. Hartw. 302. 1848. 



Ceanothus prostratus var. laxus Jepson, Man. Fl. PI. Calif. 624. 1925. 



Prostrate or low spreading shrub, the branches rooting and often forming large mats, the 

 young branchlets reddish brown, sparsely appressed-pubescent. Leaves cuneate-oblanceolate or 

 -obovate, 8-25 mm. long, several-toothed, or often with only 3 teeth at the apex, thick and coria- 

 ceous, glossy green ; flowers blue, in small umbels on short stout axillary peduncles ; capsules 

 7-9 mm. broad, with thick and wrinkled exocarp, the horns very stout, usually erect and much 

 wrinkled. 



Open pine forests, Transition and Canadian Zones; Klickitat County, Washington, southward, east of the 

 Cascade-Sierra Divide, to western Nevada and the eastern slopes of the Sierra Nevada; west of the Divide it 

 extends from Jackson County, Oregon, to Trinity County and the southern Sierra Nevada, California. Type 

 locality: originally collected by Hartweg in the northern Sierra Nevada. April-June. 



43. Ceanothus pinetorum Coville. Coville's Ceanothus. Fig. 3153. 



Ceanothus pinetorum Coville, Contr. U.S. Nat. Herb. 4: SO. 1893. 



Ceanothus prostratus var. pinetorum K. Brandg. Proc. Calif. Acad. II. 4: 211. 1894. 



Erect or more or less spreading shrub, 1-1 .5 m. high, the young branches reddish brown and 

 nearly or quite glabrous. Leaves opposite, broadly obovate to suborbicular, denticulate all around, 

 bright green and glabrous above, a little paler beneath and very sparsely or not at all strigose ; 

 flowers deep violet-purple, in densely flowered umbels ; capsule 7 mm. broad, the horns erect and 

 nearly apical, very stout and wrinkled, the intermediate exocarp also wrinkled and ridged. 



Open coniferous forests, upper Arid Transition Zone; southern Sierra Nevada, California. Type locality: 

 near Lyon Meadow, Sierra Nevada, Tulare County, California. May-June. 



44. Ceanothus Jepsonii Greene. Jepson's Ceanothus. Fig. 3154. 



Ceanothus Jepsonii Greene, Man. Bay Reg. 78. 1894. 



Erect, rigidly branched shrub, 1.5-2 m. high, the branchlets stoutly divaricate, reddish brown 

 and strigose when young. Leaves broadly oval to suborbicular, 1-2 cm. long, strongly spinose, 

 dentate all around, rigidly coriaceous and usually strongly undulate, glabrous and bright glossy 

 green above, inconspicuously strigose below ; flowers blue, in open umbels ; capsules 6-7 mm. 

 broad, horns near the apex, erect, very stout and wrinkled, the exocarp between the horns thick, 

 wrinkled and ridged. 



Rocky ridges. Upper Sonoran and Transition Zones; southern Mendocino and Lake Counties, south to 

 Marin County, California. Type locality: "Open hills in Marin County, near San Geronimo, and northward." 

 April-May. 



4. COLUBRINA Rich. Ann. Sci. Nat. 10: 368. pi. 15. fig. 3. 1827. 



Shrubs or trees, usually with rigid divaricate and sometimes spinescent branches. 

 Leaves alterucite, entire or toothed, persistent or deciduous ; stipules small and deciduous. 

 Flowers inconspicuous, in small sessile or pedunculate axillary umbels, tomentose. Calyx- 

 lobes tardily deciduous, the tube lined with the disk and adherent to the base of the 

 capsule. Petals minute, hooded and partly enclosing the anthers, sessile or short-clawed. 

 Style short, 3-lobed nearly to the base. Capsule 3-celled and more or less 3-lobed, enclos- 

 ing a single seed in each cell. [Name from Latin coluber, a serpent, the application un- 

 certain.] 



About 18 species, natives of the southern United States, Mexico, and South America; one species in the 

 Old World. Type species: Rhamniis colubrinus Jacq. 



1. Colubrina calif ornica L M.Johnston. California Colubrina. Fig. 3155. 



Colubrina calif ornica I. M. Johnston, Proc. Calif. Acad. IV. 12: 1085. 1924. 

 Colubrina texensis var. californica L. Benson, Amer. Journ. Bot. 30: 630. 1943. 



Intricately branched shrub, 1.5-2.5 m. high, the branches usually divaricate and more or less 

 spinescent and finely grayish-tomentose. Leaves oblong to oblong-obovate, 8-20 mm. long, 

 rounded or obtuse at the apex, obtuse or somewhat cuneate at the base, entire, dull grayish green 

 on both surfaces and more or less tomentose, pinnately veined ; flowers in small axillary clusters ; 

 calyx and pedicels tomentose ; capsule globose, 6 mm. broad. 



Dry gravelly washes and bajadas, Lower Sonoran Zone; Eagle Mountains, Riverside County, California; 

 also Arizona and Las Animas Bay, Lower California, the type locality. May-June. 



5. ADOLPHIA Meisn. Gen. PI. 70. 1837. 



Shrubs with stiff divaricate spine-tipped opposite branches, articulate with the stems. 

 Leaves opposite, small and mostly caducous, stipitate. Flowers inconspicuous, solitary or 

 in few-flowered axillary clusters. Calyx campanulate, 5-lobed, the lobes persistent. Petals 

 5, hooded. Ovary 3-celled, free from the calyx-tube ; style 3-cleft, articulate near the base. 

 Capsule invested at base by the persistent calyx-tube, but free from it, 3-celled and 3-lobed. 



