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evergreen buckthorn, holly leaf redberry, redberry

hollyleaf buckthorn, redberry, redberry buckthorn, spiny redberry

Habit Shrubs or small trees, 1–4 m, unarmed. Shrubs, 1.2–2(–4) m, usually armed with thorns.
Branchlets

gray, stiff, glabrous or densely and softly hirtellous.

reddish to red-purple or orange-brown; glabrous.

Leaves

persistent, alternate;

petiole 2–10 mm;

blade usually dull green, sometimes reddish brown, abaxially, glossy to dull green adaxially, broadly elliptic to oblong, orbiculate, or ovate, 2–4.5 cm, distinctly coriaceous, base cuneate to nearly truncate, margins spinulose to spinose-dentate, apex rounded or obtuse to truncate or emarginate, both surfaces glabrous;

secondary veins 5–7 pairs, all diverging at nearly same angle.

persistent, alternate;

petiole 2–6 mm;

blade usually dull green abaxially, shiny dark green adaxially, elliptic to obovate or ovate, 0.7–2 cm, distinctly coriaceous, base cuneate to truncate, margins coarsely serrate, spinulose-serrulate, or entire, apex obtuse to emarginate, both surfaces glabrous;

secondary veins 5–7 pairs, all diverging at nearly same angle.

Inflorescences

fascicles or flowers solitary.

fascicles or flowers solitary.

Pedicels

2–4 mm.

2–3 mm.

Drupes

red, globose, 4–6(–8) mm;

stones 2.

red, globose, 5–8 mm;

stones 2.

Sepals

4.

4(–5).

Petals

0.

0.

2n

= 24.

Rhamnus ilicifolia

Rhamnus crocea

Phenology Flowering Jan–Jun. Flowering (Jan–)Mar–May.
Habitat Canyon slopes and bottoms, rock faces, open hillsides, sandstone ridges, serpentine slopes, roadsides, stream benches, riparian areas, meadows, coastal sage scrub, chaparral/desert transition, chaparral, woodlands, montane forests. Dry washes and canyons, coastal and inland dunes, alluvial fans, gravel flood plains, disturbed sandy flats, brushy slopes, steep granitic slopes, woodlands, coastal sage scrub, chaparral.
Elevation 100–2200(–2400) m. (300–7200(–7900) ft.) 50–1200 m. (200–3900 ft.)
Distribution
from FNA
AZ; CA; NV; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhamnus crocea and closely related species were considered conspecific by C. B. Wolf (1938), who treated those in the flora area as subspp. crocea, ilicifolia, pilosa, and pirifolia; he also recognized subsp. insula (Kellogg) C. B. Wolf from Mexico (Baja California). The taxa are distinctive, but intermediates exist. Wolf identified R. crocea/ilicifolia intermediates from Marin County to the California/Mexico boundary, and R. ilicifolia/insula, R. crocea/pilosa, and R. ilicifolia/pilosa intermediates in southern California, especially in San Diego County.

Arizona plants (Pima County, especially in the Ajo Mountains) identified as Rhamnus crocea (for example, K. Christie 2006) appear to be populational variants of the single species present there, R. ilicifolia (R. Felger, pers. comm.). In California, where the two are sympatric over a relatively broad region, R. crocea is distinct from R. ilicifolia in usually bearing thorns and in having smaller leaves with less spinulose margins.

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

Source FNA vol. 12, p. 48. FNA vol. 12, p. 47.
Parent taxa Rhamnaceae > Rhamnus Rhamnaceae > Rhamnus
Sibling taxa
R. alaternus, R. alnifolia, R. arguta, R. cathartica, R. crocea, R. davurica, R. japonica, R. lanceolata, R. pilosa, R. pirifolia, R. serrata, R. smithii, R. utilis
R. alaternus, R. alnifolia, R. arguta, R. cathartica, R. davurica, R. ilicifolia, R. japonica, R. lanceolata, R. pilosa, R. pirifolia, R. serrata, R. smithii, R. utilis
Synonyms R. crocea subsp. ilicifolia, R. crocea var. ilicifolia
Name authority Kellogg: Proc. Calif. Acad. Sci. 2: 37. (1863) — (as ilicifolius) Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 261. (1838) — (as croceus)
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