A N F Keys
1 Flowers showy, white to lavender, violet, blue, or purple-blue; petals distinctly clawed with limb cupping anther in bud; fruit a 3-chambered schizocarpic capsule .. Ceanothus
1' Flowers nonshowy, greenish or greenish yellow; if present, petals not clawed; fruit a drupe with 2 stones
2 Blades with lateral veins conspicuously sunken on upper surface; flowers bisexual; sepals and petals mostly 5, petals < 2 mm long and whitish to pale yellow; drupes 10−12 mm diameter, ± blackish when ripe in late summer, pulp juicy .. Frangula californica subsp. californica [pics]
2' Blades without lateral veins sunken on upper surface; dioecious, each type having aborted other sex; sepals mostly 4 and petals absent; drupes 5−7.5 mm diameter, red when ripe in late spring and early summer, pulp firm .. Rhamnus
1 Blades ± thick and stiff, having stomates in pits (stomatal crypts) on lower surface; stipules ± conic, corky, and persistent; perianth and filaments white (pale violet); capsule with hornlike appendage on each segment
2 Leaves alternate; blades mostly obovate to elliptic and truncate to notched at tip; immature capsules 7.5−10(−12) mm diameter .. Ceanothus megacarpus var. megacarpus [pics]
2' Leaves opposite; blades ovate to oblanceolate or elliptic but never truncate or notched at tip
3 Blades 2−12 mm wide, entire, lower surface canescent but pits clearly visible on lower surface; stipules not touching; immature capsules 4−5 mm diameter with erect horns at tip .. Ceanothus cuneatus var. cuneatus [pics]
3' Blades 10−20 mm wide, mostly short-dentate, lower surface densely white-tomentose concealing pits; stipules mostly touching; immature capsules 5−8 mm diameter with horns on shoulders .. Ceanothus crassifolius var. crassifolius [pics]
1' Blades not unusually thick, lacking stomates in pits on lower surface; stipules thin and early-deciduous; perianth and filaments blue to purple-blue, light lavender, or light violet (white); capsule without hornlike appendages
4 Blades with only 1 vein at base, lower surface glossy; twigs and young branches remaining green (not glaucous) .. Ceanothus spinosus [pics]
4' Blades with ± 3 veins at base, lower surface dull; twigs and young branches either developing some bark or gray-glaucous
5 Leaves mostly on spine-tipped short shoots; blades conspicuously gray-glaucous, ± entire, veins not sunken on upper surface, lower surface sparsely puberulent-strigose along principal veins; flowers 5−6 mm across; pistil ca. 2.5 mm long .. Ceanothus leucodermis [pics]
5' Leaves on flexible twigs; blades dark green above and often bluish below, short-dentate to short-serrate on margins with teeth initially glandular, principal veins sunken on upper surface, lower surface ± sericeous along principal veins; flowers 4−4.5 mm across; pistil 1−1.7 mm long .. Ceanothus oliganthus var. oliganthus [pics]
1 Plants with leaves on short, sharp-pointed spur shoots; stipules ± 1.5 mm long; blades 4−18(−24) × 3−13 mm; sepals 1−1.5 mm long; staminate flowers 4−4.5 mm across with hypanthium conic to hemispheric 1−1.5 mm long .. Rhamnus crocea [pics]
1' Plants with leaves not on spur shoots; stipules 3−6 mm long; blades 15−75 × 13−62 mm; sepals 2−3 mm long; staminate flowers 5−6 mm across with hypanthium bell-shaped to funnel-shaped 2−2.5 mm long .. Rhamnus ilicifolia [pics]
The text of the above keys used with permission from
A Naturalist's Flora of the Santa Monica Mountains and Simi Hills, California
© Copyright
Barry A. Prigge and Arthur C. Gibson
2013