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John O. Sawyer, Jr., except as noted

[Perennial herb] shrub, tree, generally erect, often thorny. Leaf: simple, generally alternate, often clustered on short-shoots; stipules generally present, occasionally modified into spines; generally petioled; blade pinnate-veined or 1–5-ribbed from base. Inflorescence: cyme, panicle, umbel, or flowers 1 or clustered in axils or on short-shoots. Flower: generally bisexual, radial; hypanthium subtending, surrounding, or partly fused to ovary; sepals 4–5; petals 0, 4–5, generally clawed; stamens 0, 4–5, alternate sepals, attached to hypanthium top, each generally fitting into a petal concavity; disk (0 or) between stamens, ovary, thin to fleshy, entire or lobed, free from ovary, adherent or fused to hypanthium; ovary superior or ± inferior, chambers [1]2–4, 1–2-ovuled, style 1, stigma entire or 2–3-lobed. Fruit: capsule, drupe.
50–52 genera, 950 species: especially tropics, subtropics some cultivated (Ceanothus; Frangula; Rhamnus; Ziziphus). [Richardson et al. 2000 Amer J Bot 87:1309–1324] —Scientific Editors: Steve Boyd, Thomas J. Rosatti.
Unabridged references: [Brizicky 1965 J Arnold Arbor 45:439–463; Richardson et al. 2000 Kew Bull 55:311–341]

Key to Rhamnaceae

Shrub, small tree, < 10 m. Stem: branches alternate, stiff or flexible; twigs generally not thorn-tipped; winter bud scales present, generally ± 3 mm. Leaf: scattered along branches or clustered on short-shoots, deciduous or evergreen; stipules generally deciduous; petioles generally glabrous; blade veins prominent or not. Inflorescence: flowers 1 or in cyme-like clusters in axils. Flower: unisexual (bisexual), generally on separate plants, generally < 3 mm; hypanthium bell-shaped to cup-like, 2–3 mm wide; sepals 4–5, thin, spreading, not keeled adaxially; petals 0 or 4–5; disk thin, adhering to hypanthium; ovary appearing superior or partly inferior, chambers 2–4, each 1-ovuled, style 1, stigma 2–4-lobed. Fruit: drupe, 2–3[4]-stoned.
110 species: temperate, few tropics; some of value in medicine or as dyes. (Greek: name for plants of this genus) [Bolmgren & Oxelman 2004 Taxon 53:383–390] W.H. Brewer collected Rhamnus cathartica L., considered invasive in parts of United States, in 1861, but it apparently never naturalized. Other taxa in TJM (1993) moved to Frangula.
Unabridged references: [Wolf 1938 Rancho Santa Ana Bot Gard Monogr 1]

Key to Rhamnus

R. crocea Nutt. SPINY REDBERRY
Shrub, < 2 m. Stem: bark gray; branches many, spreading, stiff, rooting; twigs ± thorn-tipped, red or red-purple. Leaf: evergreen; petiole 1–4 mm; blade 10–15 mm, elliptic to obovate, thick, glabrous, abaxially flat, base acute to rounded, tip rounded, margin sharp-toothed or entire, veins not prominent. Inflorescence: 1–6-flowered, glabrous; pedicel 1–6 mm. Flower: generally unisexual; hypanthium ± 2 mm wide; sepals 4; petals 0. Fruit: 2-stoned, 6 mm, red.
Coastal-sage scrub, chaparral, woodland; < 1150 m. Klamath Ranges, Outer North Coast Ranges, High Sierra Nevada, Central Western California, Southwestern California; Baja California. Jan–Apr [Online Interchange]
Unabridged note: Rhamnus crocea and its closely related species were considered conspecific by C.B. Wolf (1938) (e.g., Rhamnus crocea subsp. crocea, Rhamnus crocea subsp. ilicifolia, Rhamnus crocea subsp. pilosa, Rhamnus crocea subsp. pirifolia). Another, Rhamnus insula Kellogg (Rhamnus insula subsp. insula (Kellogg) C.B. Wolf) is restricted to Mexico (Baja California). The species are distinctive but intermediates exist. C.B. Wolf (1938) identified Rhamnus crocea/ilicifolia intermediates from Marin Co. to the California/Mexicoico boundary; Rhamnus ilicifolia/insula, Rhamnus crocea/pilosa, and Rhamnus ilicifolia/pilosa intermediates occur in southern California, especially in San Diego Co. Clearly, the Rhamnus crocea complex in California needs studies using modern techniques.

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Dec 1 2015
Citation for this treatment: [Author of taxon treatment] 2013. Rhamnus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Dec 1 2015

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click for enlargement Rhamnus crocea
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2003 Charles E. Jones

Geographic subdivisions indicated for the distribution of Rhamnus crocea Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.