APIACEAE

CARROT FAMILY

Lincoln Constance

Annual, biennial, perennial herb (rarely shrub, tree), often from taproot
Stem often ± scapose, generally ribbed, hollow
Leaves basal and generally some cauline, generally alternate; stipules generally 0; petiole base generally sheathing stem; blade generally much dissected, sometimes compound
Inflorescence: umbel or head, simple or compound, generally peduncled; bracts present (in involucres) or not; bractlets generally present (in involucels)
Flowers many, small, generally bisexual (or some staminate), generally radial (or outer bilateral); calyx 0 or lobes 5, small, atop ovary; petals 5, free, generally ovate or spoon-shaped, generally incurved at tips, generally ± ephemeral; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a ± conic, persistent projection or platform on top subtending 2 free styles
Fruit: 2 dry, 1-seeded halves that separate from each other but generally remain attached for some time to a central axis; ribs on each half 5, 2 marginal and 3 on back; oil tubes 1–several per interval between ribs
Genera in family: 300 genera, 3,000 species: ± worldwide, especially temp; many cultivated for food or spice (e.g., Carum, caraway; Daucus; Petroselinum); some highly toxic (e.g., Conium). Underground structures here called roots, but true nature remains problematic. Mature fruit generally critical in identification; shapes generally given in outline, followed by shape in X -section of 2 fruit halves together.

APIUM

Annual, biennial, perennial herb, taprooted or fibrous-rooted from horizontal rhizome
Stem prostrate to erect, hollow, rooting from lower nodes or not, glabrous
Leaf: blade oblong to obovate, 1-pinnate or ternate-pinnately dissected, leaflets paired, lanceolate or ± round (segments linear)
Inflorescence: umbels compound, peduncled or not; bracts, bractlets conspicuous to 0; rays, pedicels few, spreading-ascending
Flower: calyx lobes 0 or minute; petals wide, white or greenish white; projection atop ovary sometimes flat
Fruit ovate-oblong to round, compressed side-to-side; ribs subequal, thread-like to obtuse and corky; oil tubes per rib-interval 1; fruit axis entire or notched at tip
Seed: face flat
Chromosomes: 2n=22
Species in genus: ± 20 species: generally s hemisphere (South America, s Africa, Australia, New Zealand), also Eurasia, 2 species weedy in CA
Etymology: (Classical name for celery)

Introduced

A. nodiflorum (L.) Lag.

Plant 1.5–10 dm
Stem rooting at lower nodes
Leaf: petiole 3 dm; blade 10–20 cm, oblong, leaflets ± 6 cm, lanceolate to ovate, crenate but terminal 3-lobed
Inflorescence: rays 10–20, 1.5–2 cm, unequal; calyx lobes 0
Fruit 1.5–2 mm diam, ovate-oblong; fruit axis entire
Ecology: Wet places
Elevation: generally < 1000 m.
Bioregional distribution: e San Francisco Bay Area (reported from Niles Canyon, Alameda Co., 1933)
Distribution outside California: native to Eurasia
Sporadically naturalized in temp zones worldwide.