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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

RHAMNACEAE BUCKTHORN FAMILY

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

1. Flowers conspicuous; petals generally 5; petals, sepals, pedicels white to deep blue or pink ..... CEANOTHUS

1' Flowers inconspicuous; petals 0–5, generally green or white; sepals, pedicels white, green, or gray

2. Fruit a capsule

3. Branches opposite, green; twigs jointed at base; South Coast, Peninsular Ranges ..... ADOLPHIA

3' Branches alternate, ± white; twigs not jointed at base; s Mojave Desert, Sonoran Desert ..... COLUBRINA

2' Fruit a drupe

4. Fruit of 2–4 separate stones; widespread

5. Winter bud scales 0; petals 5; sepals fleshy, erect, keeled adaxially ..... FRANGULA

5' Winter bud scales present; petals 0 or 4–5; sepals thin, spreading, not keeled adaxially ..... RHAMNUS

4' Fruit of 1 stone; Desert, e Peninsular Ranges, South Coast

6. Petals 0; disk 0 or thin in early flower ..... CONDALIA

6' Petals 5; disk thick, ± obscuring ovary in early flower ..... ZIZIPHUS

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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