Vascular Plants of Williamson County

Fleischmannia incarnata [Asteraceae]
pink slender thoroughwort, pink boneset

Fleischmannia incarnata (Walter) R. M. King & B. H. Robins., pink slender thoroughwort, pink boneset. Perennial herb, several–stemmed at base, lax and spreading to ascending , < 50 cm tall; shoots with only cauline leaves, gland–dotted, with curled short hairs and straight, short glandular hairs, strongly aromatic.

Stems

Stems with inconspicuous ridges, mostly < 1.5 mm diameter, green with nonglandular and glandular hairs.

Leaves

Leaves opposite decussate, simple, petiolate and pair with ledges across node, without stipules; petiole narrowly channeled, in range 3—13 mm long, pubescent like stem; blade triangular to deltate, in range 5—30 × 3—18 mm, cordate to truncate at base, serrate on margins, acute at tip, 3–veined at base with veins sunken on upper surface and raised on lower surface, with soft short hairs, lower surface gland–dotted

Inflorescence

Inflorescence head, in terminal on principal and short lateral branches (having 1—2 with diminutive leaves), flat–topped array, array ± open, of principal axis having several alternate branches each cymelike and flat–topped, heads < 8—many, head with 15—20(—25) discoid flowers, ca. 5 mm across, bracteate, pubescent like stems; bract subtending the lowest peduncle leaflike, 3–lobed having opposite, teethlike lateral lobes, < 5 mm long, upper bracts awl–shaped, ± 3 mm long; peduncle of the lower axis slender, 20—60+ × ± 0.6 mm, with several helically alternate bracts along axis (= future branches), bracts < 2 mm long; involucre narrowly inversely conic to funnel–shaped, in range 4—5.5 × (3—)3.5—4 mm, phyllaries 14—20 in several series, unequal, outer phyllaries narrowly triangular to lanceolate, 2.5—4 mm long, green, short–hairy with some glandular hairs, inner phyllaries longer, ± linear–oblong, 0.5—0.7 mm wide with membranous margins and tip, with 2 prominent veins and sessile glands mostly in vertical rows, tip fringed; bractlet (palea) subtending flower absent; receptacle narrow and flat, glabrous.

Flower

Flower bisexual, radial, 1.5 mm across; calyx (pappus) ca. 25 capillary bristles in 1 series, 2.5—3 mm long, white, firmly attached; corolla 5–lobed. narrowly funnel–shaped with widely spreading lobes, glabrous; tube + throat 3—3.3 mm long, 0.6 mm wide at orifice, tube light yellow–green, throat white; lobes deltate, 0.35—0.45 mm long, white to faint pink; persistent and still colored in fruit; stamens 5, attached to top of corolla tube; filaments 1 mm long, white; anthers fused into cylinder surrounding style, partially exserted, basifixed, dithecal, 1 mm long, light yellow with erect, white, obtuse appendages 0.2—0.3 mm long, longitudinally dehiscent; pollen white; nectary disc surrounding base of style; pistil 1; ovary inferior, 5–sided, 2—2.3 × 0.3 mm, greenish with ascending short hairs along 5 ribs, having callus at base, 1–chambered with 1 ovule; style 2–branched below orifice of corolla, green to midpoint, the branches stigmatic, when pollinated at level of anthers later conspicuously exserted and curled, slender (filiform), 2—3 mm long, white often aging pinkish.

Fruits

Fruits cypselae (achenes) with firmly attached pappus of capillary bristles, cypsela slender wedge–shaped and 5–ribbed, ca. 2.2 mm long, brown, gradually tapered to callus at base, with ascending short hairs along ribs; pappus in 1 ring, ca 3 mm long, white.

A. C. Gibson