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. gracilenta Torr. & A. Gray

Annual 3–60 cm
Stem greenish
Leaves 2–13 cm; basal lobed (comb-like); lower cauline many-lobed, upper entire to few-lobed
Inflorescence: bract generally fused to ovary base, obovate, 3–12-toothed, white below middle
Flower: sepals 3–8 mm; petals 7–18 mm, base generally with orange spot; stamens ± = style; style 5–11 mm
Fruit generally 9–10(23) mm, 3–5 mm wide, straight or curved < 20°
Seed 1.5–2.5 mm, grain-like, round-papillate; angles sharp
Chromosomes: n=18
Ecology: Steep talus, pine/oak woodland
Elevation: 200–1500 m.
Bioregional distribution: South Coast Ranges, Western Transverse Ranges
Synonyms: M. ravenii H.J. Thompson & J.E. Roberts
Horticultural information: DRN, DRY, SUN: 2, 3, 7, 14, 15, 16, 18, 19, 20, 21; DFCLT.