Flora of North America species comparison

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Ceanothus cuneatus

Ceanothus cuneatus var. cuneatus

buck brush, common buckbrush, narrow-leaf buckthorn, sedge-leaf buckthorn, wedgeleaf cuneatus
Photo is of parent taxon

buck brush
Habit Shrubs, 0.5–3.5 m. Stems erect, ascending, or spreading, not rooting at nodes; branchlets grayish brown to brown, rigid or flexible, glabrate, puberulent, or tomentulose, hairs straight. Shrubs, 1.5–3.5 m. Stems erect; branchlets grayish brown to light gray, glaucous.
Leaves

usually both fascicled and not fascicled on same plant, rarely none fascicled;

petiole 1–3 mm;

blade flat to cupped, elliptic, oblanceolate, obovate, or orbiculate, 4–22(–30) × 3–12(–22) mm, base rounded, margins thick, not revolute, entire or denticulate distal to middle, teeth 0–9, apex obtuse, rounded, truncate, or retuse, abaxial surface pale green, glabrate or glabrous, adaxial surface green, glabrous.

blades of fascicled and non-fascicled leaves flat, elliptic to widely oblanceolate, 6–22(–30) × 3–12(–22) mm, length usually 2+ times width, margins entire, apex usually obtuse to rounded, rarely truncate.
Inflorescences

axillary or terminal, 0.8–2.5 cm.

Flowers

sepals, petals, and nectary white to lavender or blue.

sepals, petals, and nectary usually white, sometimes pale blue or pale lavender.
Capsules

4–6 mm wide, weakly lobed;

valves smooth, horns subapical, prominent, erect, intermediate ridges absent.

4–6 mm wide.
2n

= 24.

Ceanothus cuneatus

Ceanothus cuneatus var. cuneatus
Phenology Flowering Jan–May.
Habitat Rocky slopes, ridges, sometimes on serpentine, chaparral, oak and oak-pine woodlands, conifer forests, gravelly floodplains.
Elevation 10–1900 m. (0–6200 ft.)
Distribution
from FNA
CA; OR; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR; Mexico (Baja California)
[BONAP county map]
Discussion

Varieties 4 (4 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Variety cuneatus in Oregon and in the Klamath Mountains of northern California is characterized by relatively small, elliptic to oblanceolate leaf blades 6–12 millimeters. The type specimen, collected by David Douglas in the upper Willamette Valley of Oregon, falls within this range. Low-growing, moundlike plants in the Klamath Mountains, less than eight tenths of a meter, with spreading stems, leaves similar in size and shape, and white to pale blue sepals and petals, are treated here as Ceanothus arcuatus. Elsewhere, var. cuneatus is characterized by leaf blades 9–30 millimeters.

Shrubs to 3.5 meters with large leaf blades 15–30 × 9–18(–22) millimeters have been named Ceanothus cuneatus var. dubius J. T. Howell, and are restricted to sandy soils and open sites in chaparral and mixed evergreen forests of the Santa Cruz Mountains. Plants in the Transverse and Peninsular ranges of southern California, with narrowly oblanceolate leaf blades with sparsely canescent abaxial surfaces, have been named C. oblanceolatus Davidson. Putative hybrids with C. pauciflorus have been reported from several localities in the southern Sierra Nevada (H. McMinn 1944). Formally named hybrids involving var. cuneatus include C. ×connivens Greene (either with C. prostratus or C. fresnensis), C. ×flexilis McMinn (with C. prostratus), and C. ×humboldtensis Roof (with C. pumilus).

Wood of var. cuneatus was used by Native Americans to make tools and arrow foreshafts (D. E. Moerman 1998).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Leaf blades of fascicled and non-fascicled leaves elliptic to widely oblanceolate, length usually 2+ times width; sepals, petals, and nectaries usually white, sometimes pale blue or pale lavender.
var. cuneatus
1. Leaf blades of fascicled and non-fascicled leaves widely oblanceolate, widely obovate, or orbiculate, length usually less than 2 times width, or of fascicled leaves elliptic to narrowly oblanceolate (in var. fascicularis); sepals, petals, and nectaries usually lavender to blue, sometimes pale blue, rarely white.
→ 2
2. Leaf blades of fascicled leaves elliptic to narrowly oblanceolate, 9–15 × 3–6 mm, length usually 2+ times width.
var. fascicularis
2. Leaf blades of fascicled leaves widely oblanceolate, widely obovate, or orbiculate, 4–15 × 3–12 mm, length less than 2 times width.
→ 3
3. Leaf blade margins usually entire, rarely 1–4-toothed, apices rounded, truncate, or retuse.
var. ramulosus
3. Leaf blade margins 5–9-toothed, apices rounded to truncate.
var. rigidus
Source FNA vol. 12, p. 99. FNA vol. 12, p. 99.
Parent taxa Rhamnaceae > Ceanothus > subg. Cerastes Rhamnaceae > Ceanothus > subg. Cerastes > Ceanothus cuneatus
Sibling taxa
C. americanus, C. arboreus, C. arcuatus, C. confusus, C. cordulatus, C. crassifolius, C. cyaneus, C. dentatus, C. divergens, C. diversifolius, C. fendleri, C. ferrisiae, C. foliosus, C. fresnensis, C. gloriosus, C. griseus, C. hearstiorum, C. herbaceus, C. impressus, C. incanus, C. integerrimus, C. jepsonii, C. lemmonii, C. leucodermis, C. maritimus, C. martini, C. masonii, C. megacarpus, C. microphyllus, C. oliganthus, C. ophiochilus, C. otayensis, C. palmeri, C. papillosus, C. parryi, C. parvifolius, C. pauciflorus, C. perplexans, C. pinetorum, C. prostratus, C. pumilus, C. purpureus, C. roderickii, C. sanguineus, C. sonomensis, C. spinosus, C. thyrsiflorus, C. tomentosus, C. velutinus, C. verrucosus
C. cuneatus var. fascicularis, C. cuneatus var. ramulosus, C. cuneatus var. rigidus
Subordinate taxa
C. cuneatus var. cuneatus, C. cuneatus var. fascicularis, C. cuneatus var. ramulosus, C. cuneatus var. rigidus
Synonyms Rhamnus cuneata C. cuneatus var. submontanus, C. oblanceolatus
Name authority (Hooker) Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 267. (1838) unknown
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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