Vascular Plants of Williamson County

Aphanostephus ramosissimus var. ramosissimus [Asteraceae]
plains lazydaisy

Aphanostephus ramosissimus var. ramosissimus DC., plains lazydaisy. Annual, taprooted, not rosetted, several–stemmed at base, with spreading to ascending branches, in range to 18 cm tall; gynomonoecious; shoots with cauline leaves petiolate (lower primary shoots) and sessile, axes and foliage short–hirsute (most < 0.5 mm long) with spreading (deflexed backward) nonglandular hairs and with scattered, short glandular hairs having minute, colorless heads.

Stems

Stems ridged, to 2 mm diameter, with 1 or 3 ridges descending from each leaf, having a glossy, bulbous, pulvinuslike swelling at base of each branch and branchlet.

Leaves

Leaves helically alternate, unlobed or on primary shoots weakly pinnately lobed to 3–lobed above midblade, petiolate (larger lobed leaves) and sessile, without stipules; petiole flattened top–to–bottom, flared at base, < 8 mm long, indistinct from blade; blade oblanceolate to oblong, to 40 mm long, lobes < 3 mm long, long–tapered at base (petiolate) or with a pair of basal leaves not or slightly clasping (sessile), entire or with tooth on margins, obtuse at tip, 1–veined with midrib slightly raised on upper surface and raised on lower surface, short–hirsute and with minute glandular hairs.

Inflorescence

Inflorescence head, terminal, solitary or in 3–headed cymelike array, head radiate, 16—27 mm across, in range of ca. 25 pistillate ray flowers and ca. 200 bisexual disc flowers, disc 5—8 mm across, bracteate, green tissues short–hirsute and with short glandular hairs having minute, colorless heads; peduncle 6–ridged, < 20—45 mm long, green or appearing striped, compressed approaching head, hairs mostly deflexed, with 1—2 1–veined, oblong to lanceolate bracts along peduncle with 3 ridges descending from bract, 3—10 × 1 mm long, having raised midvein on lower surface, lacking bracts at top (calyculus); involucre saucerlike, 4—5 mm long, short–hirsute and glandular–hairy, of 25—40 phyllaries in 3—5 series, outer phyllaries ca. 8 in 2 series, lanceolate to elliptic, ca. 2.5 × 0.5 mm, green or some scarious tip or thin margins, middle and inner phyllaries, 3—4.2× 0.8—1.6 mm, mostly scarious with decreasing green center, jagged on scarious margins, acute at tip, intermediate phyllaries green–raised on back; receptacle hemispheroid, 3.5—4 × 3.5—4 mm, sometimes hollow beneath receptacle, shallowly pitted with low rim around each disc flower ovary, glabrous.

Ray flower

Ray flower bilateral, < 2 mm across; calyx (pappus) short–crownlike, short–ciliate rim < 0.15 mm long; corolla unlobed or with 2—3 minute teeth at tip, never coiled; tube swollen at base and cylindric above, ca. 1 × 0.3 mm, greenish; limb oblanceolate, in range 5.5—7 × 1.3—2 mm, pure white; stamens absent; pistil 1; ovary inferior, ± cylindric slightly curved, 1 × 0.4 mm, greenish, short–strigose with upward–pointing hairs, 1–chambered with 1 ovule; nectary disc surrounding base of style < 0.1 mm long, colorless; style exserted, 2–branched, 1.6—1.9 mm long, colorless at base, the stigmatic branches 0.4—0.5 mm long, pale yellow.

Disc flower

Disc flower radial, 1 mm across (corolla), 3 mm long; calyx (pappus) short–crownlike, short–ciliate rim < 0.15 mm long; corolla 5–lobed; tube cylindric, < 1 × 0.3 mm, colorless, with several papillate hairs above midpoint; throat ± cylindric and low 10–ribbed, 0.7 × 0.4 mm, colorless (weak yellow) with 5 yellow veins to sinuses, lacking hairs; lobes at some point spreading, triangular, 0.4—0.5 mm long, golden yellow; stamens 5, attached at top of corolla tube; filaments slender, ca. 0.5 mm long, pale golden yellow; anthers fused into cylinder surrounding style, basifixed, dithecal, 1 mm long incl. triangular appendages, golden yellow, tips of appendages exserted, longitudinally dehiscent; pollen golden yellow; pistil 1; ovary inferior, 4–sided wedge–shaped, 0.5 mm wide, white, short–strigose with upward–pointing hairs, 1–chambered with 1 ovule; nectary disc minute, around base of style, colorless; style partially exserted from corolla throat and anthers, 2 mm long, 2–branched, colorless at base becoming yellowish at midpoint, the stigmatic branches divergent and ascending, 0.5 mm long, golden yellow.

Fruits

Fruits cypselae (achenes), somewhat dimorphic, of ray flowers ± cylindric, ca. 0.8 × 0.4 mm, brownish, short–strigose, of disc flowers 4–sided wedge–shaped weakly ribbed, 1.1—1.2 × 0.7 mm, tannish, short–strigose; pappus = a minutely ciliate rim < 0.15 mm long, erect.

A. C. Gibson