CACTACEAE

CACTUS FAMILY

Edward F. Anderson (except Opuntia)

Perennial, shrub, tree, generally fleshy
Stem cylindric, spheric, or flat; surface smooth, tubercled, or ribbed (fluted); nodal areoles bear flowers, generally bear spines from center ("central spines") and margin ("radial spines") (Opuntia areoles bear small, barbed, deciduous bristles sometimes called glochids, generally also bear spines)
Leaf generally 0
Flower generally solitary, bisexual, sessile, ± radial; perianth parts generally many, grading from scale-like to petal-like; stamens many; ovary appearing inferior, ± submerged in stem, so generally with areoles on surface, style 1, stigma lobes generally many
Fruit generally fleshy, generally indehiscent, spiny, scaly, or smooth
Seeds many
Genera in family: 93 genera, ± 2000 species: especially Am deserts; many cultivated
Etymology: (Greek: thorny plant)
Reference: [Benson 1982 Cacti of US & Can; Hunt & Taylor eds 1990 Bradleya 8:85–107]

ECHINOCACTUS

CLUSTERED BARREL CACTUS

Stems 1–30, often in ± 1 m diam clumps, each 3–6 dm, 10–20 cm diam, spheric to columnar; ribs 13–21, prominent; tubercles indistinct; spines dense
Flower 4–5 cm diam; perianth yellow tinged with pink
Fruit dry, densely woolly
Seed 2–2.5 mm, 2–3.5 mm diam, black
Species in genus: 6 species: sw US, Mex
Etymology: (Greek: hedgehog cactus)

Native

E. polycephalus Engelm. & J.M. Bigelow var. polycephalus

Stem < 1 m; central spines 4, 6–7.5 cm, red or yellow, canescent at first, spreading, lowermost curved slightly; radial spines 6–8, 3–4.5 cm, spreading, slightly curved, red or yellow
Flower: ovary densely woolly, with sharp-tapered bracts, style ± 20 mm
Chromosomes: 2n=22
Ecology: Rocky hills, silty valleys
Elevation: < 1000 m.
Bioregional distribution: eastern San Bernardino Mountains, Mojave Desert, n Sonoran Desert
Distribution outside California: to Arizona, Mexico
Flowering time: Mar–May
Horticultural information: DRN, DRY: 2, 3, 10, 11, 12, 13, 19 &SUN: 20, 21.