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island redberry

alder buckthorn, alder leaf coffeeberry, alder-leaf buckthorn, American alder-buckthorn, dwarf alder, nerprun á feuilles d'aulne

Habit Shrubs to small trees, 2.5–6(–10) m, unarmed. Shrubs, 0.5–1(–1.5) m, unarmed.
Branchlets

purple to gray, glabrous or puberulent.

gray to brown, glabrous or pubescent.

Leaves

persistent, alternate;

petiole 5–10 mm;

blade dull reddish to yellowish brown abaxially, usually shiny green adaxially, broadly elliptic to oblong or ovate-oblong, (1.5–)2–5(–6) cm, distinctly coriaceous, base cuneate to nearly truncate, margins blunt-serrate or entire, apex acute to rounded, apiculate, both surfaces glabrous;

secondary veins 5–9 pairs, all diverging at nearly same angle.

deciduous, alternate;

petiole 5–15 mm;

blade dark green to olive green on both surfaces, lanceolate-oblong to elliptic or lanceolate-ovate, 4.5–11 cm, herbaceous, base cuneate to rounded, truncate, or subcordate, margins crenate to crenate-serrate, apex obtuse to acute or acuminate, abaxial surface glabrous or puberulent along veins, adaxial surface glabrous or glabrate;

secondary veins (4–)5–7 pairs, all diverging at nearly same angle.

Inflorescences

fascicles or flowers solitary.

fascicles or flowers solitary.

Pedicels

3–6 mm.

2–10 mm.

Drupes

red, globose, 6–8 mm;

stones 2.

black, globose or slightly elongate, 6–8 mm;

stones 3.

Sepals

4.

5.

Petals

0.

0.

Rhamnus pirifolia

Rhamnus alnifolia

Phenology Flowering (Jan–)Feb–Jun. Flowering May–Jul.
Habitat Steep slopes, canyon walls and bottoms, dunes, grasslands, coastal sage scrub, chaparral, pine woodlands. Fens and swamps, generally calcareous, riparian thickets, interdunal swales, shore lines, marshes and mats, wet meadow edges, outcrops, deciduous and coniferous forests.
Elevation 10–500 m. (0–1600 ft.) 10–2700 m. (0–8900 ft.)
Distribution
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CT; IA; ID; IL; IN; MA; MD; ME; MI; MN; MT; ND; NH; NJ; NY; OH; OR; PA; RI; SD; TN; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhamnus pirifolia is known in California on the Channel Islands and in Baja California on Guadalupe Island; it has not been implicated in hybridization with other members of the R. crocea complex.

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

Rhamnus alnifolia is a primary host for the soybean aphid.

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

Source FNA vol. 12, p. 47. FNA vol. 12, p. 49.
Parent taxa Rhamnaceae > Rhamnus Rhamnaceae > Rhamnus
Sibling taxa
R. alaternus, R. alnifolia, R. arguta, R. cathartica, R. crocea, R. davurica, R. ilicifolia, R. japonica, R. lanceolata, R. pilosa, R. serrata, R. smithii, R. utilis
R. alaternus, R. arguta, R. cathartica, R. crocea, R. davurica, R. ilicifolia, R. japonica, R. lanceolata, R. pilosa, R. pirifolia, R. serrata, R. smithii, R. utilis
Synonyms R. crocea subsp. pirifolia, R. crocea var. pirifolia
Name authority Greene: Pittonia 3: 15. (1896) L'Héritier: Sert. Angl., 3. (1789) — (as alnifolius)
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