LOASACEAE

LOASA FAMILY

Barry Prigge

Annual to shrub; hairs needle-like, stinging, or rough
Leaves alternate in CA, generally ± pinnately lobed; stipules 0
Inflorescence various
Flower bisexual, radial; sepals generally 5, generally persistent in fruit; petals generally 5, free or fused to each other or to filament tube; stamens 5–many, filaments thread-like to flat, sometimes fused at base or in clusters; petal-like staminodes sometimes present; pistil 1, ovary inferior, chamber generally 1, placentas generally 3, parietal, style 1
Fruit: generally capsule (utricle)
Seeds 1–many
Genera in family: 15 genera, ± 200 species: especially Am (Africa, Pacific)
Reference: [Ernst & Thompson 1963 J Arnold Arbor 44:138–142]

MENTZELIA

BLAZING STAR

Annual to shrub; hairs generally barbed-rough (smooth)
Leaf linear to ovate, generally ± lobed; basal in rosettes, generally petioled; cauline generally sessile, ± reduced upward
Inflorescence: generally cyme (or flower 1); bract generally 1 per flower, generally green
Flower: sepals lanceolate to deltate, generally persistent; petals 5, free, generally yellow; stamens generally many, ± free, generally unequal, inner filaments generally thread-like; staminodes 0 or 5–many, outer often petal-like; ovary generally cylindric, placentas generally 3, style thread-like, stigma 3-furrowed or -lobed
Fruit generally tapered to base, sometimes curved
Seeds generally many, grain- to prism-like (triangular in X -section), angled, or lenticular and winged (important to identification)
Species in genus: ± 50 species: w US, ± tropical Am
Reference: [Darlington 1934 Ann Missouri Bot Garden 21:103–226]

Native

M. involucrata S. Watson

Annual 7–35 cm
Leaves 2–18 cm, generally irregularly toothed
Inflorescence: bracts 4–5 per flower, (ob)ovate, white-scarious, margin green, 3–10-toothed or -lobed
Flower: sepals 7–23 mm; petals 13–62 mm, cream-yellow with orange veins; stamens 4–26 mm, filament 2-toothed at tip; style 8–30 mm
Fruit 14–22 mm, 5–10 mm wide, straight
Seed 2–3 mm, 2–2.5 mm wide, ± compressed, beaked, narrowed above and below middle, rough, ashy white
Ecology: Washes, fans, steep slopes, creosote-bush scrub
Elevation: < 900 m.
Bioregional distribution: Desert
Distribution outside California: n Mexico
Flowering time: Jan–May
Plants from n DSon, with petals > 30 mm, have been called var. megalantha I.M. Johnst
Horticultural information: TRY.