Vascular Plants of Williamson County

Lindheimera texana [Asteraceae]
texas star, star daisy

Lindheimera texana A. Gray & Engelm., texas star, star daisy. Annual, robust, thick–taprooted, ± rosetted, 1–stemmed at base, beginning in canopy with ascending, flowering lateral branches, erect, (10—)30—120+ cm tall; monoecious; shoots with basal leaves and cauline leaves, ± hispid with hairs to 3 mm long, with inconspicuous, widely scattered, minute glandular hairs, foliage not aromatic.


Stems ± cylindric, to 12 mm diameter, light green, densely hispid; hollow.


Leaves helically alternate, simple, petiolate (basal leaves) and sessile (cauline leaves), without stipules; petiole flattened, to 30 × 4 mm, indistinct from blade; blade oblanceolate (basal leaves) to ± elliptic or broadly lanceolate (cauline leaves), 60—170 × 15—65 mm, long–tapered at base, coarsely serrate on margins but often entire approaching tip, blunt–acute to obtuse or slightly notched at tip, conspicuously pinnately veined and 1–veined from base, principal veins ± sunken on upper surface and conspicuously raised on lower surface, with shorter hispid hairs on margins, midrib whitish on both surfaces and to 6 mm wide at base.


Inflorescence heads, in leafy, cymelike arrays, array terminal on each shoot, heads on long, erect pedicel (to 110 mm long), head radiate, 25—30 mm across, with 4—5 pistillate ray flowers and 12—35+ functionally staminate disc flowers, bracteate, hispid and short–hispid with scattered glandular hairs; bract subtending each ascending bract, at base of flowering canopy 3 ± whorled or 2 opposite, with erect pedicel in center, at other nodes mostly 2 and opposite, decussate at successive nodes, each bract leaflike, spreading, sessile, ovate, to 110 × 55 mm decreasing upward, clasping axis base but not fused across node, with several teeth below midblade to entire, acute at top, upper surface pilose–hispid and lower surface mostly short–hairy; inflorescence internodes densely hairy; pedicel at anthesis to 25 mm long, mostly short–hairy, with scattered long–hispid hairs but also with scattered, tack–shaped hairs to 0.4 mm long having bright green heads, at the top of pedicel having a whorl of 5 bracts (calyculus, alternatively = outer phyllaries), initially ascending several mm above and free at base, lanceolate, 12—15 × 3—4 mm increasing to 20 × 5 mm and reflexed and persistent in fruit, 3–veined at base with a conspicuous midvein, having a blunt, reddish point at acuminate tip, mostly short–hairy with the longest hairs on margins with several tack–shaped hairs; involucre cup–shaped, 8—12 mm wide (excluding calyculus), phyllaries (4—)5 in 1 series opposite each ray flower, phyllaries ovate, 12—16 × 6—9 mm increasing to 22 × 11 mm in fruit, green, ± obtuse and blackish at tip, with 5+ principal veins, short–strigose (outer surface) and with shorter hairs on inner surface; receptacle ± domelike, with bractlet (palea) subtending each disc flower, paleae inrolled around ovary and concealing lower portion of disc flower, oblong–oblanceolate, 7.5—8.3 mm long, rounded on back, to midpoint whitish and glabrous, above midpoint mostly pale golden yellow and short–hairy on outer surface, acute at tip.

Ray flower

Ray flower pistillate, bilateral, 3.5—8 mm across; calyx (pappus) absent (awnlike structures = part of ovary); corolla shallowly 2–toothed, sometimes with a diminutive third middle tooth, or lacking teeth, with some tack–shaped hairs on tube and lower limb on the outer side and margins; tube compressed front–to–back, ca. 2 mm long, pale yellow, short–hairy; limb obovate, 10—14 mm long, bright yellow, with 5—10 parallel veins not conspicuously pigmented, short–hairy on lower surface; stamens absent; pistil 1; ovary inferior, obovate in outline and strongly compressed front–to–back and with 2 awnlike structures on top, ca. 7.5 mm long (including “awns”), outer face convex, 6 — 5 mm, center glabrous and outer portion short–hairy with upward–projecting hairs, inner face concave with central rib and covered with mostly milky, club–shaped hairs, center at top with a curving, tail–like appendage hooked upward; style exserted, 3—3.5 mm long, 2–branched, pale orange, branches 0.5—1 mm long.

Disc flower

Disc flower appearing bisexual but functionally staminate, radial, 2.5—3 mm across; calyx (pappus) absent (awnlike structure of ovary); corolla 5–lobed, funnel–shaped; tube slightly 5–sided, 0.6—0.7 mm long, white, glabrous, throat ca. 2 mm long, golden yellow, with 5 veins to sinuses; lobes spreading, ± deltate, 1 mm long, with short hairs on edges and outer surface, conspicuously papillate on inner (upper) surface; at anthesis tube + throat filled with nectar; stamens 5, fused to corolla just below throat, exserted 1.5 mm; filaments ± 2 mm long, pale yellow; anthers fused in cylinder surrounding style, basifixed, dithecal, ± 1.9 mm long, striped purple and orangish, longitudinally dehiscent; pollen orange–yellow; pistil 1, sterile; ovary inferior, cylindric, white, lacking ovule; style with nectary at base, exserted slightly above anthers, 5—5.3 mm long, not branched, white and glabrous at base, above 1.5 mm golden yellow, conspicuously papillate above midpoint.


Fruits cypselae, monomorphic, dispersal unit of inner phyllary (palea) with appressed cypsela and 2 short–stalked, strongly inrolled paleae of adjacent disc flowers; phyllary spreading in starlike arrangement, obtuse–elliptic to ovate, 9—15(—22) × 4.6—7(—11) mm, light brown with fine brown veins, entire, uniformly short–hairs with ascending, straight, stiff hairs; cypsela 2–“awned” and winged, seed body with wings obovate and strongly flattened, ca. 6 × 5 mm, convex on hidden surface next to phyllary, seed body double–convex, glossy black (blue–green when immature), glabrous on hidden surface and conspicuously white, stiff–hairy on exposed surface with curved hairs, wing cupped, 1 mm wide, light brown and short–strigose, awnlike structures (part of ovary and not calyx) acuminate, 1.5—2 mm long, with tack–shaped hairs (also top of ovary); paleae to level of awns, light brown, short–hairy, including shriveled ovary of disc flower.

A. C. Gibson