460 RHAMNACEAE 



Dry ridjres and canon sides, 50 to 3000 feet : Napa Co. and sontli near the coast 

 to Santa Barbara and San Diego. South to Lower California. Mar.-Apr. 



Locs. — IIowcll Mt., Napa Eaiige, Jcpson G587 ; Mt. George (n. of), Napa Range, Jepson 

 13,970; Berkeley, Davy 833; Mission Hills, San Francisco, Grccfic ; Stanford, C. F. Baker 609; 

 Guadalupe Mine, Santa Clara Co., Jcpso7i 9093; Monterey, Brewer G36; betw. Sans Mill and San 

 Miguelito ranch, Santa Lucia Mts., Jepson 1678; San Luis Obispo, Condit. S. Cal.: Mission 

 Canon, Santa Barbara, Eastivood; Los Alisos Canon, Santa Monica Mts., Epling ; Arroyo Seco 

 (foothills w.), San Gabriel ISIts., Feirson 339; San Bernardino, Farish ; San Jacinto, Gregory; 

 betw. Cahuilla Valley and Aguanga, w. Riverside Co., Jepson 1481; Mt. Soledad, Newlon 335; 

 San Diego, If. F. Spencer 134. 



Var. ilicifolia Greene. Erect, often tree-like with a distinct trunk, or the stems several and 

 clustered, 3 to 12 feet high; branchlets rather stout, repeatedly and shortly branched at the 

 ends, making a twiggy or clumpy growth ; leaf -blades oval to orbicular, often golden beneath, 

 spinulose-dentate, 4 to 12 lines long; calyx-lobes and stamens 4 or often 5; berry bright red, 

 ovoid, 21/2 lines long. — Dry liills and caiion flats, 1000 to 4000 feet: inner Coast Ranges from 

 Trinity Co. to San Luis Obispo Co. ; Sierra Nevada from Shasta Co. to Kern Co. ; coastal Southern 

 California. 



Locs. — Coast Ranges: Willow Creek, Trinity River valley, Tracy 5959; Cortina Valley, sw. 

 Colusa Co., C. J. Wilcomh; Little River, Mendocino Co., Bolander 4806; Round Valley, ne. 

 Mendocino Co., Goddard 233; Miller Canon, Vaca Mts., Jepson; Twin Sisters Peak, Napa Range, 

 Jepson 2389 ; Donner Caiion, Mt. Diablo, Jepson 7583 ; upper San Benito River at Lorenzo Creek, 

 Jepson 12,231; Atascadero, San Luis Obispo Co., Brewer 510. Sierra Nevada: Goose Valley, 

 Shasta Co., Baker 4- Nutting; Knights Ferry, e. Stanislaus Co., F. W. Bancroft; Hetch-Hetchy, 

 Chesnut 4- Drew; Yosemite, Ahrams 4488; Kinsley, Mariposa Co., Charlotte II oak ; Three Rivers, 

 Coville # Funston 1299; Grouse Valley, Tulare Co., Jepson 4713; Fay Creek, "Weldon, Kern Co., 

 W. F. Taylor. S. Cal.: Providence Mts., T. Brandegee; Manzana, Antelope Valley, Davy 2541; 

 Zaca Lake, Santa Barbara Co., Condit; Sespe Creek, Ventura Co., Rowland 4" Darsie ; Pine Canon, 

 w. of Elizabeth Lake, J. B. Ball 6h ; Altadena, C. E. HutcJmison ; Eaton Canon, San Gabriel Mts., 

 Feirson 109; Devils Punch Bowl, San Gabriel Mts., Feirson 287; Beaumont, Riverside Co., Gil- 

 man; Mt. San Jacinto, C. V. Meyer 164; Claymine Caiion, Santa Ana Mts., Howell 2824; "Warner 

 Hot Sprs., ne. San Diego Co., J. A. Feam ; Banner Canon, San Diego Co., Chandler 5458; "Witch 

 Creek, San Diego Co., Alderson; Campo, San Diego Co. (Bull. N. Y. Bot. Gard. 6:406). 



Var. insularis Sarg. Tree 15 to 30 feet high; similar to var. ilicifolia; leaves less promi- 

 nently or scarcely at all toothed ; berries larger. — Santa Barbara Islands : Santa Catalina Isl., 

 Jepson 3042 ; Santa Cruz Isl., Jepson 12(,081. 



Var. pilosa Trel. Leaves more or less puberulent or pilose. — Mountains of San Diego Co., 

 both cismontane and transmontane : Ramona, E. Brandegee ; San Diego, Mary Spencer 135. 



Refs.— Rhamnus crocea Nutt.; T. & G. Fl. N. Am. 1:261 (1838), type loc. Monterey, 

 Nuttall; Cm-ran, Proc. Cal. Acad. ser. 2, 1:251 (1888); Jepson, Fl. W. Mid. Cal. 254 (1901), 

 ed. 2, 252 (1911), Man. 615, fig. 616 (1925). Var. ilicifolia Greene, Fl. Fr. 79 (1891). B. ilici- 

 folia Kell. Proc. Cal. Acad. 2:37 (1859), type loc. Clear Lake, Lake Co., Veatch. Var. insularis 

 Sarg. Gard. & For. 2:364 (1889), Silva N. Am. 2:34, t. 60 (1891). B. insularis Greene, Bull. Cal. 

 Acad. 2:392 (1887), Pitt. 1:201 (1888). B. pirifolia Greene, Pitt. 3:15 (1896), type loc. Santa 

 Cruz Isl., Greene. B. catalinae Dav. Bull. S. Cal. Acad. 16:47 (1917), type loc. Santa Catalina 

 Isl., Davidson 2344. Var. pilosa Trel.; Curran, Proc. Cal. Acad. ser. 2, 1:251 (1888), type loc. 

 Santa Maria Valley, San Diego Co., Palmer 38. B. pilosa Abrams, Bull. Torr. Club 37:153 

 (1910), Bull. N. Y. Bot. Gard. 6:406 (1910). 



3. CEANOTHUS L. 



Shrubs or small trees "with petioled leaves, the branchlets often divaricate and 

 rigid, sometimes spinescent. Flowers small but showy, borne in panicles or um- 

 bels. Calyx 5-lobed, the lower part adnate with the thick disk to the lower part of 

 the 3-celled ovary. Petals 5, hooded by the inflexion of the acuminate apex, and 

 with long claws. Stamens 5, filaments filiform, long-exserted. Style 3-clef t. Cap- 

 sule subglobose, 3-celled, 3-lobed, becoming dry and separating into its 3 carpels, 

 these elastically dehiscent along the inner edge and dispersing the seeds. Seeds 

 obovate, convex on the back. — Species about 40, North America. (Greek Keano- 

 thus, name used by Dioscorides to designate some spiny plant.) 



Biol. note. — The roots of Ceanothus thyrsiflorus bear mycorrhizal nodules in abundance. 

 Our first observation was made on Mt. Tamalpais in 1912. In the same year nodules were fre- 

 quently found on the root system of Ceanothus foliosus. In all probability all other species of 

 this genus develop such structures. Compare the illustrations of Ceanothus foliosus (fig. 227) 

 and Ceanothus rigidus (fig. 237). 



