Eclipta prostrata (L.) L., false daisy. Annual, taprooted and fibrous–rooted, 1—several–stemmed from base, typically forming pairs of branches at most nodes in canopy, often rooting at lower nodes, prostrate to decumbent or ascending, in range < 50 cm tall; gynomonoecious; shoots with only cauline leaves, scabrous, strigose.
Stems cylindric, to 3 mm diameter, green to purplish red, with internodes to 120 mm long and ± flaring below each node.
Leaves opposite decussate, simple, sessile, without stipules; blade linear–lanceolate to narrowly elliptic or elliptic (lower leaves), 20—125 × 7—24 mm, shallowly short–serrate on margins, acute to acuminate at tip, pinnately veined with principal veins raised on lower surface, strigose with conspicuous hair bases.
Inflorescence heads, in terminal and axillary, 1—several cymelike arrays, head radiate, 6—8 mm across, of 30—50 ray flowers and ± 30—50 disc flowers, bracteate, strigose; bract subtending array leaflike; peduncle 4—20 mm, densely strigose, lacking bracts along axis; involucre hemispheric, 3.5—5 mm diameter, becoming cup–shaped and increasing to 2× in fruit, phyllaries typically 8 in 1(2) series, ovate, 3.5—5 mm long, outer phyllaries > inner phyllaries, green, 3—5–veined, strigose appearing ciliate on margins, with acute tips spreading (to 2 mm beyond ray flowers) and becoming appressed to fruits; receptacle slightly domed, with bractlets (paleae), palea bristlelike, 1.5—2.5 mm long, having upward–pointing barbs above midpoint. Ray flower: pistillate, bilateral, ca. 0.5 mm across; calyx (pappus) absent or vestigial = jagged rim (with 2 minute awns); corolla unlobed or shallowly 2–lobed, 2—2.4 mm long, whitish; tube cylindric, < 0.5 mm long; limb linear, obtuse, with flattened bristles at base + top of tube; stamens absent; pistil 1; ovary inferior, narrow wedge–shaped, ± 1.2 mm long, green and whitish, 3—4–sided; style exserted, ± 0.7 mm long, 2–branched, the branches short and whitish tinged rose at tip.
Disc flower bisexual, radial, 0.5 mm across; calyx (pappus) absent or vestigial = jagged rim (with 2 minute awns); corolla 4(—5)–lobed, ca. 1.5 mm long, whitish; tube short; throat ± 0.7 mm long; lobes deltate, ± 0.3 mm, with several stout hairs on 1 lobe and 0—several hairs on other lobes; stamens 4(—5), fused to top of corolla tube, slightly exserted; filaments free; anthers fused into cylinder surrounding style, basifixed, dithecal, 0.6 mm long, pale yellow, longitudinally dehiscent; pollen pale yellow; pistil 1; ovary inferior, narrow wedge–shaped, ± 1.2 mm long, green and whitish, 3—4–sided; style slightly exserted, 2–branched, the branches short.
Fruits cypselae, monomorphic, (3—)4–sided, slightly compressed wedge–shaped, in range 1.7—2.2 × 0.7—1 mm, when immature bright white with green tips, maturing brown, sides typically warty (tuberculate), top truncate and with short hairs + the jagged remnant of style base; pappus (if present) a jagged rim, occasionally with 2 awns < 0.2 mm long.
A. C. Gibson & B. A. Prigge