Amblyolepis setigera DC., huisache daisy. Annual, taprooted, not rosetted, 1–stemmed at base, with ascending branches, erect to ascending, in range 9—35 cm tall; gynomonoecious; shoots with only cauline leaves, somewhat glaucous, pubescent with long pilose hairs, foliage when handled pleasantly sweetly fragrant like alfalfa (Medicago).
Stems cylindric, to 4 mm diameter, pale green and whitish striped, with scattered pilose hairs to 4 mm long and pilose hairs visible also in leaf axils.
Leaves helically alternate, simple and sessile and clasping to short–petiolate, without stipules; petiole (if recognized) on lower leaves, cupped, to 1 mm long; blade oblanceolate (lower leaves) to ovate, 11—35 × 4.5—17 mm, symmetric to asymmetric and tapered to subcordate at base, entire and often pilose–ciliate on margins, acute at tip, pinnately veined with midrib raised on lower surface, surfaces dull, glabrous, somewhat glaucous light green, and without visible lateral veins.
Inflorescence heads solitary, terminal on long peduncle, head radiate, (16—)25—30+ mm across, in range of (3, 5, or 8 pistillate ray flowers and 4—25+ bisexual disc flowers, bracteate; bract subtending peduncle = the uppermost cauline leaf; peduncle 5–ridged or 8–ridged, 50—120 × 0.35 mm aging 1 mm diameter, with scattered pilose hairs; involucre saucer–shaped, in range of 3, 5, or 8 spreading phyllaries in 1 series, subtending ray flowers, free to base, acute–lanceolate, in range (5.2—)8—10 × (1.2—)2.2—3 mm, mostly green and somewhat glaucous but often with membranous margins below midblade and colorless margins above midpoint to tip, pilose–ciliate on margins, lower surface pilose to midblade; receptacle hemispheric to conic, in range with bractlets subtending outer series of disc flowers (paleae) persistent in fruit and other disc flowers with spreading, starlike crown with 4—5 deltate teeth surrounding each ovary, crown to 0.4 mm long, conspicuous on receptacle after fruit abscise.
Ray flower bilateral, 2.5—6 mm across; calyx (pappus) of 4—6 suberect, scarious, obovate or fan–shaped to ovate scales, 3.2—4 × 1.2—4 mm, colorless lacking thickened midvein, venation, and awns, upper margin obtuse to acute, jagged and often cut, persistent; corolla 2—3–lobed, glabrous; tube cylindric, (1—)1.6—2 × 0.55—0.6 mm, ± orange–yellow; limb fan–shaped to inverted arrow–shaped, (5—)10—13 × (3.2—)4—6.3 mm, bright yellow, 3–veined at base with 2 veins to each lobe converging at tip, lobes subequal, acute, 1—4 × 0.9—1.2 mm, minutely papillate on upper surface tip–to–base; stamens absent; nectary disc surrounding style base 0.15 mm long, whitish; pistil 1; ovary inferior, wedge–shaped but concealed by dense, ascending straight hairs, 1.5 × 0.8 mm, light green, strongly 10–ribbed with hairs along ribs, the hairs projecting above ovary; style exserted, 2—2.5 mm, 5 mm long, orange–yellow, 2–branched, the branches stigmatic, channeled, 1 mm long, lacking stigmatic disc at tip.
Disc flower bisexual, radial, 2—2.5 mm across, 7.8—8.5 mm long; calyx (pappus) of 5—6 suberect, scarious, obovate to ovate scales, ca. 3 × 1—1.3 mm, colorless or with fine purple streaks, lacking thickened midvein, venation, and awns, upper margin obtuse to acute, jagged, persistent; corolla 5–lobed, 4.8—6 mm long, glabrous; tube cylindric, 1— 1.6 × 0.5 mm, yellowish; throat narrowly funnel–shaped, 2—3 mm long, ca. 1.6 mm wide at orifice; lobes triangular, 1—1.6 × 0.7—0.9 mm, bright yellow; stamens 5, attached at top of corolla tube; filaments flat and broad, ca. 2 mm long, yellowish; anthers fused as cylinder surrounding style, 2.2—2.4 mm including ovate appendages 0.8 mm long, orangish yellow alternating with membranous panels, longitudinally dehiscent; pollen yellowish; nectary disc surrounding style base, 0.2—0.25 mm long; pistil 1; ovary inferior, columnar but concealed by dense, ascending straight hairs, 1.6—1.8 mm, light green, strongly 10–ribbed with hairs along ribs, the hairs projecting above ovary; style ca. 5 mm long, 2–branched, yellowish from base, orange–yellow from fork, the branched spreading, channeled, 1.2—1.4 mm long, with disclike stigma at tip, the disc 0.5 mm across and conspicuously papillate–hairy.
Fruits cypselae (achenes), of ray flowers top–shaped and conspicuously 10–ridged, in range 2.8—3.2 × 1.8—2.2 mm, tan, ribs beige–tannish with spreading fine hairs, furrows with reddish sessile glands, of disc flowers inversely narrowly pyramidal, in range 2.8—3.2 × 0.7 mm, 10–ribbed; pappus scales 4—6, ascending, scarious, obovate to ovate, ca. 3 mm long, lacking thickened midline, veins, and awns.
A. C. Gibson