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]

MAMMILLARIA

NIPPLE CACTUS, FISH-HOOK CACTUS

Stems 1–many, 2–30 cm, 2–20 cm diam, spheric to cylindric; ribs inconspicuous; tubercles round in X -section; central spines generally hooked
Flower 1–5 cm diam; ovary glabrous
Fruit ovoid to cylindric, red, glabrous
Seed black, pitted
Species in genus: 150 species: North America
Etymology: (Latin: nipple)
Reference: [Hunt 1984–87 Bradleya 2:65–96; 3:53–66; 5:17–48]

Native

M. tetrancistra Engelm.

Stem generally 1, 7–25 cm, 3.5–7.5 cm diam, cylindric; axillary bristles 0; central spines 3–4, 18–25 mm, generally hooked, tips dark; radial spines 30–60 in 2–3 ranks, 10–25 mm, white or tips dark
Flower 30–40 mm, 25–40 mm diam; perianth deep pink to lavender
Fruit 15–32 mm, cylindric
Seed: aril corky
Chromosomes: 2n=22
Ecology: Uncommon. Sandy hills, valleys, plains, creosote-bush scrub
Elevation: 130–1400 m.
Bioregional distribution: Desert
Distribution outside California: to Utah, Arizona, n Mexico
Flowering time: Apr
Horticultural information: DRN, DRY; DFCLT.