BUCKTHORN FAMILY 465 



(1925). C. impressus Trel. Proc. Cal. Acad. ser. 2, 1:112 (1888), type loc. Santa Barbara Co., 

 Sara A. Plummer. 



7. C. parrjd Trel. Lady-bush. Shrub 4 to 6 (or 18) feet high; branchlets 

 angular and, when young, tomentose, the 1-year-old ones reddish; leaf -blades pin- 

 nately veined, narrowly to broadly oblong, % to 21^ inches long, dark green above, 

 finely cobwebby-tomentose beneath, the margin denticulate but seemingly entire 

 because soon revolute; petioles 2 lines long; panicles simple, oblong or distinctly 

 broader below, 1 to 3 inches long, on sparsely leafy peduncles twice as long; bract- 

 lets white, hairy; flowers blue; capsules globose, smooth, 2 lines broad. 



Wooded caiions and mountain slopes, 100 to 2500 feet : Napa and Sonoma Cos. 

 to Humboldt Co. Apr.-June. 



Field note. — Ceanothus parryi is closely related to C. thyrsiflorus. These species are in 

 addition very similar in habit and appearance, but C. parryi has more open branching and the 

 bractlets of its inflorescence are very white. C. thyrsiflorus is distinctively a Kedwood associate, 

 while C. parryi grows further inland ; it is, for example, very common in the chaparral of western 

 Lake Co. The two are sometimes associated as in Humboldt Co., but C. thyrsiflorus is vastly 

 more abundant, especially in the Eedwood belt, while here again C. parryi ranges further inland. 



Locs. — Betw. Mt. George and MillDcen Creek, Napa Range, Jepson 14,385; St. Helena (w. 

 of), Jepson; Calistoga, Jepson 14,023; Mt. St. Helena, Jepson 10,372; Howard, Sonoma Co., 

 Rivers; Green Valley, w. Sonoma Co., M. S. BaTcer ; Scotts Valley, w. Lake Co., Tracy 1728; 

 betw. Halfway House and Low Gap, Mendocino Co., Jepson; betw. Briceland and Garberville, 

 Jepson; Mail Ridge, Humboldt Co., Jepson 16,388; Hubbard sta. near Camp Grant, Jepson 

 1906 ; Weott, Humboldt Co., Jepson 16,491 ; Kneeland Prairie, n. Humboldt Co., Tracy 5823. 



Refs. — Ceanothus parryi Trel. Proc. Cal. Acad. ser. 2, 1:109 (1888), type cult, at Calis- 

 toga, Parry; Jepson, Fl. W. Mid. Cal. 256 (1901), ed. 2, 254 (1911), Man. 618 (1925). C. inte- 

 gerrimus var. parryi K. Bdg. Proc. Cal. Acad. ser. 2, 4:183 (1894). 



8. C. thyrsiflorus Esch. Blue Brush. Shrub 3 to 8 feet high, or becoming 

 a small tree up to 18 or 25 feet high, rather straight-limbed, the branchlets strongly 

 angled and mostly ascending; leaf -blades elliptical or oblong-ovate, green on both 

 surfaces, glabrous and shining above, paler and usually scantily hairy along the 

 veins beneath, strongly 3-nerved beneath, the margin mucronate-serrate or serru- 

 late with somewhat impressed glandular teeth, % to 2 inches long; panicles dense, 

 % to 3 inches long, on somewhat leafy peduncles 2 to 4 inches long; flowers blue, 

 rarely varying to white; capsules globose, smooth, little lobed, 1^/2 to 2 lines broad, 

 glandular and black when ripe. 



Wooded canon sides or hill slopes, 10 to 1500 feet : along the coast from Mon- 

 terey Co. to Del Norte Co. North to Oregon. Mar.-June. 



Geog. note. — Ceanothus thyrsiflorus reaches its greatest development in the westerly por- 

 tions of the Redwood belt. On the Mendocino coast we have observed dense stands of slender 

 poles of this species as much as 18 to 25 feet high. Broadly speaking this species does not occur 

 in the dense parts of mature or virgin Redwood stands, but it is one of the first species to appear 

 on logged areas and is usually one of the dominants in the logged creek basins. Its two most 

 common associates are Vaccinium ovatum Pursh and Myrica californica Cham. The prevailing 

 form has large leaves with 3 strong primary ribs. On the inner margins of its range or in arid 

 habitats, the leaves are smaller and the lateral ribs less marked. It is a strictly coastal species, 

 never known in the middle or inner Coast Ranges. It is the only Ceanothus species in the Red- 

 wood belt north of the lower main Eel River (J. P. Tracy). The two trees discovered at Placer- 

 ville by F, B. Herbert can scarcely be indigenous. 



The root-system of Blue Brush is shallow, so that this species is readUy killed completely 

 by chaparral fires. On account of this surface root-system tall poles in the Mendocino woods are 

 easily overthrown and usually occur more or less leaning. It does not crown-sprout. We first 

 observed mycorrhizal tubercles on the roots in 1912, and it is of some interest that large or old 

 well-grown trees occupy pockets of rich soil in the hills. Individuals of considerable size have 

 been measured as follows: Mt. Tamalpais, pipe-line trail, 16 feet high, trunk 26 inches circum- 

 ference at two feet: Ferndale, on Wildcat grade, tree 18 feet high, 28 inches circumference at 20 

 inches; between Mendocino City and Gonsalves ranch, tree 20 feet high, 3 feet in circumference 

 at 3 inches. The greatest development of the species in size appears to be in the pure colonies 

 between Usal and Cottonaby Creek, Mendocino coast. 



Locs. — Pacific Grove, Jepson 14,007; Monterey, Jepson 2994; Little Arthur Creek, w. of 

 Gilroy, Jepson 9685 ; Soquel Creek, Santa Cruz Mts., Jepson 13,433 ; Boulder Creek, Santa Cruz 



