Vascular Plants of Williamson County

Hedypnois cretica [Asteraceae]
Crete weed

Hedypnois cretica (L.) Dum. Cours., Crete weed. Annual, taprooted, rosetted, 1–stemmed at base, 6—30(—40) cm tall; shoots with prostrate to ascending basal leaves and clasping cauline leaves, hirsute–hispid becoming ± scabrous, the hairs mostly 2(3)–barbed at tip; latex milky.

Stems

Stems cylindric at base to many–ridged above, to 3 mm diameter, with ridges descending from cauline leaves, coarsely hairy with barb–tipped hairs along ridges.

Leaves

Leaves helically alternate, simple, petiolate (basal leaves) and sessile and clasping (cauline leaves), without stipules; petiole flat and narrowly winged, < 10 mm long and indistinct from blade, white, often inrolled and sparsely short–ciliate on margins; blade oblanceolate to spatulate or narrowly oblong, 35—180 × 8—32 mm, long–tapered at base, dentate with shallow teeth or shallowly pinnately lobed on margins, acute to obtuse at tip, pinnately veined with midrib raised on lower surface, dull green, with scattered hairs, the hairs unbranched and short–forked at tip.

Inflorescence

Inflorescence heads, initially solitary and terminal later in cymelike array of several heads, head ligulate, 12—15 mm across, of 37—45 flowers, flowers to 7 mm above involucre, bracteate, scabrous with mostly barbed and forked hairs; bract subtending peduncle = cauline leaf; peduncle many–ridged, ascending to erect, 7—100 mm long, becoming thicker and hollow approaching head, coarsely hirsute–hispid with barb–tipped hairs along ridges, somewhat compressed in fruit; sometimes with bracts along axis, bracts leaflike, narrowly lanceolate to narrowly oblong, entire or short–dentate; bracts at top of peduncle subtending head generally 7—10 (calyculus), appressed, unequal, narrowly lanceolate, 2—5.5 mm long; involucre narrowly bell–shaped, ca. 5 mm wide, phyllaries ± 13 phyllaries in 2 series, equal, linear, ± 8 mm long, base fleshy, bluntly keeled with narrowly winged margins enveloping ovary of the outermost flowers and incurved and hardened in fruit, hispid, inner phyllaries initially with tips folded over unopened flower buds; receptacle flat, without bractlets (paleae), shallowly pitted with a crownlike border surrounding each ovary.

Ligulate flower

Ligulate flower bisexual, bilateral, ca. 2 mm across; calyx (pappus) of 5 fused scales crownlike and jagged (outer flowers) to 10 free scales in 2 series (central flowers), scales if 5 erect to ascending, 0.3—1 mm long, scarious, many–toothed, of central flowers inner series with 1—5 flat–based bristles to 5 mm long; corolla shallowly 5–toothed; tube cylindric, 2.5—4 mm long, white, with spreading, stiff, straight hairs at top and on the lower limb; limb spreading, wedge–shaped, 5.5—6 × 1.3—2.3 mm, bright yellow with purple teeth, 6–veined (to sinuses + edges); stamens 5, fused to top of corolla tube; filaments ca. 1 mm long, whitish; anthers fused into cylinder surrounding style, exserted, basifixed, dithecal, ca. 2.5 mm long, bright yellow, tails 0.6 mm long, appendages at tip triangular, longitudinally dehiscent; pollen bright yellow; pistil 1; ovary inferior, cylindric, 3—4 mm long, greenish white, 10–ribbed, the ribs rigid short–strigose, 1–chambered with 1 ovule; style exserted beyond anthers, ca. 6 mm long, yellowish at base to bright yellow above midpoint, barbed, 2–branched, the branches spreading and later recurved.

Fruits

Fruits cypselae, dimorphic, without beak; fruit bodies of 28—35 outer fruits curved, ± cylindric, 5.5—6 mm long, 0.6—1 mm diameter at base slightly tapering to tip, of 9—10 central fruits straight–cylindric, 5—5.5 × 0.4 mm and ± uniform diameter base to tip, dark brown to blackish, ribbed, with triangular, semitransparent, scabrous scales along ribs, central fruits ca. 15–ribbed; pappus of outer fruits crownlike of fused scales with many teeth, tannish to light brown, if 10 scales of outer series triangular or lanceolate to oblong, 0.5—1 mm long, fringed, inner scales ascending, lanceolate–needlelike, 3.8—5.5 mm long, tannish to whitish; the outermost fruits with appressed, hardened phyllary firmly attached at base.

A. C. Gibson & B. A. Prigge