Brickellia cylindracea A. Gray & Engelm., gravel–bar brickellbush. Subshrub, winter–dieback to ground, several—many–stemmed from base, with ascending principal branches, in range 45—115 cm tall; shoots with only cauline leaves, foliage having short and shaggy hairs aging somewhat scabrous and gland–dotted with nearly sessile glandular hairs, mildly aromatic.
Stems ± cylindric aging low–angled and woody, to 4 mm diameter, internodes 30—55 mm long and not striped, short–tomentose and with comparatively few short–stalked glandular hairs.
Leaves opposite decussate, simple, petiolate, without stipules; petiole slightly channeled only at base, to 5 mm long, aging purplish on exposed side; blade narrowly ovate to lanceolate, 20—60 × 10—20(—30) mm, tapered at base, serrate on margins, acute at tip, 3–veined from just above base with principal veins and minor veins sunken on upper surface and principal veins raised on lower surface.
Inflorescence heads, in short axillary flowering shoots, flowering shoots 2 per node and ± equal at each node, heads (1—)2—6 per shoot in leafy clusters, head discoid, ca. 3 mm across, 8—11–flowered, bracteate, coarse short–hairy and sparsely glandular–hairy; axillary flowering shoots 2 and subequal per node, with (1—)2—6 heads and alternate bracts subtending branchlet or peduncle, the lowest bract subsessile, leaflike, and acute–lanceolate, decreasing upward; peduncle lax, cylinder, at anthesis 3—4 mm long increasing 2× in fruit, coarsely short–tomentose and with short glandular hairs; involucre initially ± cylindric, to 11 × 3 mm, aging lanceoloid–cylindric with ascending phyllaries, phyllaries 16—21 in several series, unequal, 2.6—11.6 × (0.6—)0.9—1.2 mm, tannish striped green (with reddish patch) aging tan and brown with narrow membranous margins, ± short–hairy on outer phyllaries narrowly ovate and inner phyllaries linear–lanceolate to strap–shaped, outer < 1/2 inner phyllaries and sparsely glandular–hairy, phyllaries conspicuously striped and ribbed, inner phyllaries mostly acuminate with short point and appressed–ciliate at tip, glabrous on faces, persistent; receptacle top–shaped with craters for callus of flowers, without bractlets (paleae), glabrous.
Disc flower bisexual, radial, ca. 0.7 mm across; calyx (pappus) of ca. 45 capillary bristles in 1 whorl, straight, ca. 6 mm long, white; corolla 5–lobed; tube narrowly cylindric, 7.5—8 mm long, 5–veined to sinuses; lobes erect, acute, 0.4 mm long, whitish to pale yellowish green; stamens 5, fused to corolla tube ca. 2.3 mm from base, ± included; filaments ca. 2 mm long, colorless; anthers free, basifixed, monothecal, ca. 2 mm long, light orange, rounded at base, elliptic at tip with pale orange, oblong appendage, longitudinally dehiscent; pollen pale orange; nectary fringed crown surrounding base of style, 0.5 × 0.5 mm, pinkish with whitish fringe; pistil 1; ovary inferior, ± cylindric tapered to base, 4—4.2 × 0.8—0.9 mm, angled and 10–ribbed, off–white to pale green at top, appressed short–villous, 1–chambered with 1 ovule; style exserted 2 mm, to 10 mm long, glabrous, 2–branched, whitish becoming pale yellowish green above midpoint, branches hemicylindric, ca. 6.5 mm long, ca. 0.7 mm diameter, cream (hidden portion) to greenish yellow.
Fruits cypselae, straight, ± club–shaped, 4—4.2 mm long, low 10–ribbed, brown, short–villous with ascending to appressed hairs, with a small whitish hemispheric callus at base attached somewhat laterally; pappus persistent, bristles fused at base and spreading, ca. 45 in 1 series, subequal, straight, ca. 7 mm long, white, short–barbed.
A. C. Gibson