RUBIACEAE

MADDER FAMILY

Lauramay T. Dempster

Annual, perennial herb, shrub, vine, tree
Leaves generally opposite, entire; stipules generally on stem, sometimes leaf-like (then leaves apparently whorled and stipules considered leaves), adjacent pairs sometimes fused
Inflorescence: cyme, panicle, cluster, or flower solitary, generally terminal and ± axillary
Flower generally bisexual; calyx generally ± 4-lobed, sometimes 0; corolla generally radial, 4-lobed; stamens epipetalous, alternate corolla lobes, generally included; ovary generally inferior, chambers generally 2 or 4, style 1, ± fused if 2
Fruit: 2 or 4 nutlets or a berry, drupe, or capsule
Genera in family: ± 500 genera, 6000 species: worldwide, especially tropical; many cultivated (including Coffea , coffee; Cinchona , quinine; many ornamental)
Reference: [Dempster 1979 Fl CA 4(2):1–47]

CEPHALANTHUS

BUTTON BUSH

Shrub, small tree
Leaves opposite or in whorls of 3; stipules not leaf-like
Inflorescence: head, dense, spheric, peduncled
Flower: calyx 4-toothed; corolla narrowly funnel-shaped; style 1, thread-like, exserted, stigma ± spheric
Fruit: 2–4 nutlets, wider at top
Species in genus: ± 17 species: warm-temp Am., Asia, s Africa
Etymology: (Greek: head flower)

Native

C. occidentalis L. var. californicus Benth.

CALIFORNIA BUTTON WILLOW

Plant 2–10 m
Stem when young round, reddish, glabrous
Leaf 7–20 cm, elliptic or ovate, petioled, becoming glabrous
Inflorescence 3–3.5 cm; peduncle 2.5–5 cm
Flower: corolla white or yellowish, tube slender, lobes obtuse; stigma exserted to 4 mm
Ecology: Lake, stream edges
Elevation: 3–1000 m.
Bioregional distribution: Inner North Coast Ranges, Sierra Nevada Foothills, Sacramento Valley, San Joaquin Valley (common)
Distribution outside California: to Texas, Mexico
Horticultural information: SUN, WETorIRR: 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.