Vascular Plants of Williamson County

Krigia wrightii [Asteraceae]
wright’s dwarfdandelion

Krigia wrightii (A. Gray) K. L. Chambers ex K. J. Kim, wright’s dwarfdandelion. Annual, fine–taprooted, not rosetted, 1—several–stemmed at base, with ascending branches having inflorescences, in range 7—15 cm tall; shoots with basal leaf and several cauline leaves (bracts), foliage sparse, easily wilted, glabrous; latex milky.

Stems

Stems cylindric, slender.

Leaves

Leaves helically alternate (lower leaves) to opposite or subopposite (bracts) but unequal at each node (anisophyllous), simple, petiolate and sheathing, without stipules; petiole half–sheathing, crescent–shaped in ×–section with membranous wings for sheath, < 20 mm long, indistinct from blade; blade lanceolate to oblanceolate, to 30 × 6 mm, long–tapered at base, entire, acute to obtuse at tip, pinnately veined with midrib raised on lower surface.

Inflorescence

Inflorescence head, terminal and axillary in open cymelike array, each head arising from fork of ascending branches, head ca. 4 mm across, of ± 13 bisexual, ligulate flowers, bracteate, with conspicuous, radiating stalked glandular hairs on peduncle and sometimes on involucre; bract subtending peduncle (cauline leaf) sessile and ovate; peduncle to 60 × 0.5 mm, yellow–green and glaucous, radiating glandular hairs to 0.4 mm long with swollen bases, the densest hairs approaching involucre and persistent, lacking bracts subtending involucre (calyculus); involucre at anthesis ± bell–shaped, ca. 4.5 × 2 mm, wider at base and ovoid in fruit, phyllaries 5 in 1 series fused < 1 mm, overlapping, ovate, ca. 4 × 1—2 mm, yellow–green and glaucous, outer 2 phyllaries without membranous margins, overlapped phyllaries with 1 or 2 wide membranous margins sometimes aging pink, certain phyllaries drying with well–defined keel below midpoint; receptacle domed with radiating arms and sunken where the outermost flowers are produced, without bractlet (paleae), glabrous.

Ligulate flower

Ligulate flower bilateral, ca. 1 mm across; calyx (pappus) of ca. 5 scarious and jagged scales in 1 series, erect to ascending, 0.1—0.4 mm long, brownish, persistent; corolla unlobed (minutely toothed), in range 3.2—3.5 mm long; tube 0.9—1 × 0.15 mm, colorless to yellowish; throat funnel–shaped, to 0.4 mm long, light yellow, with short glandular hairs; limb before anthesis inrolled as cylinder, spreading, elliptic, ca. 2 × 1 mm, < phyllary, light yellow; stamens 5, fused to top of corolla tube; filaments ca. 0.7 mm long, whitish; anthers fused into cylinder surrounding style, basifixed, dithecal, ± 1.2 mm including yellowish threadlike tails, light orange–yellow, longitudinally dehiscent; pollen light orange–yellow; pistil 1; ovary inferior, obovoid, 0.45—0.5 × 0.35—0.4 mm, green, minutely 15–ribbed, 1–chambered with 1 ovule; style slightly exserted above anthers, ca. 3 mm long, orange–yellow minutely barbed, 2–branched near tip, the branches spreading, 0.4 mm long, and stigmatic.

Fruit

Fruit cypselae (achenes) barrel–shaped, 1—1.4 × 0.5—0.6 mm, brown, 15–ribbed having 5 2–forked principal ribs branched near base alternating with 5 minor ribs; pappus scales scarious, 0.1—0.4 mm long.

A. C. Gibson