Common Name: BUCKTHORN FAMILY
Habit: [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.
Genera In Family: 50--52 genera, 950 species: especially tropics, subtropics some cultivated (Ceanothus; Frangula; Rhamnus; Ziziphus).
eFlora Treatment Author: John O. Sawyer, Jr., except as noted
Scientific Editor: Steve Boyd, Thomas J. Rosatti.

Common Name: CALIFORNIA-LILAC
Habit: Shrub, tree-like or not, generally erect or mat- to mound-like. Stem: branches generally arranged like leaves; twigs thorn-like or not, generally not angled. Leaf: alternate or opposite, some clustered on short-shoots or not, deciduous or evergreen; stipules scale-like, thin, deciduous, or knob-like, corky, thick, base persistent; blade flat or wavy, tip generally acute to obtuse, margin thick (i.e., thicker than adjacent blade) or not, rolled under or not, wavy or not, entire or gland- or sharp-toothed, glands generally dark, teeth pale, alternate blade 1--3-ribbed from base, generally thin, opposite blade 1-ribbed from base, thick, firm. Inflorescence: umbel-, raceme-, or panicle-like aggregations of few-flowered clusters, axillary or terminal; pedicels white to deep blue or pink. Flower: conspicuous, generally < 5 mm; hypanthium surrounding fleshy disk below ovary base, in fruit thick, not splitting; sepals generally 5, lance-deltate, incurved, colored like petals, persistent; petals generally 5, blade hood-like, white to deep blue or pink; stamens generally 5, opposite petals; ovary 1/2-inferior, 3-lobed, chambers 3, each 1-ovuled, styles 3. Fruit: capsule, +- spheric, generally +- 3-lobed, generally smooth, 3-ridged or not, horned or not. Seed: 3, 2--5 mm.
Etymology: (Greek: thorny pl) Note: Hybrids possibly common (named hybrids not recognized here), discussed in Fross & Wilken; possible hybrid forms do not key easily.
eFlora Treatment Author: Dylan O. Burge & Dieter H. Wilken
Reference: Fross & Wilken 2006 Ceanothus. Timber Press; Burge et al. 2015 Syst Bot 40:950--961.

Habit: Plant erect, open, < 4 m. Stem: ascending to erect; twigs brown to gray-brown. Leaf: opposite or alternate, evergreen; stipules knob-like; petiole 1--4 mm; blade 10--25 mm, 5--12 mm wide, length generally > 2 × width, elliptic to widely oblanceolate, adaxially dull green, glabrous, abaxially gray-green, short-strigose, especially veins, tip truncate to +- notched, margin entire, +- thick near middle, not rolled under. Inflorescence: umbel-like, 1--2 cm. Flower: generally white, disk dark. Fruit: 7--12 mm wide, 3-ridged or not; horned or not.