Description

Ephemeral herb or short-lived annual, erect, single stemmed or occasionally with 2 or 3 upper branches, 10–26 (–35) cm tall, with a slender tap root; stem glabrous (Fig.1). Leaves cauline, occasionally a basal pair present. Lamina of basal pair, simple, filiform, opposite, sessile, connate at base and forming collar around stem. Upper cauline leaves alternate, occasionally opposite or clustered around branching points; petioles absent. Lamina of upper cauline leaves decurrent to shallowly stem clasping at base, simple, entire to trilobed; entire leaves linear, filiform or terete, 1.5–7.5 cm long x 0.5–1 mm wide, lateral lobes linear, filiform or terete to 9–15 mm long; mucronate with mucro to 0.4 mm long, sometimes shallowly recurved, midvein visible abaxially when dry; multicellular hairs present on young leaves.

Inflorescence a few solitary terminal capitula on long peduncles up to 8 cm long; peduncles glabrescent, multicellular hairs present when young; occasionally with a leaf like bract below the capitula, bract herbaceous with narrow scarious irregular margin. Capitula radiate with ray florets on the margin and tubular flowers in the middle, to 10 mm diameter (excluding limb on ray florets) and 8 mm long (excluding limb on ray florets) (Fig.2a–b).

Phyllaries 2 to 3, often 2 large and 1 smaller, occasionally with a bract intermediate in form between phyllaries and paleae but not subtending a floret. Phyllary overall shape obtriangular, herbaceous with a scarious margin (Fig.2c). Herbaceous centre narrowly oblong /narrowly elliptic,(2.5–) 3–5.6 (–8) mm long x 0.5–0.9 mm wide, concave when fresh, green, occasionally drying with yellow tinge; apex acute with recurved or straight mucro; multicellular hairs sparse on inner surface of herbaceous centre. Scarious margin present along length of bract or occasionally underdeveloped and asymmetric, margin reduced or up to 0.4 mm wide with an erose edge, broadening to a truncate apex finishing at or below herbaceous tip; white; multicellular hairs along edge of distal broadening (obscure in dried specimens).

Paleae present, up to 9 per capitula, subtending each floret, overall shape narrowly obcordate (obovate with emarginate apex), petaloid with a scarious margin, concave when fresh and cradling floret. The petaloid centre variable in shape, narrowly oblong, narrowly elliptic, narrowly lanceolate or narrowly oblanceolate, (4.6–) 5–6 mm long x (0.5–)1 –1.8 (–2) mm wide, yellow; apex acute; abaxial surface with a central ridgeline or shallow keel; multicellular hairs with a stout base and a long bent threadlike tip dotted along ridgeline and scattered across apex of palea. Scarious margin present along length of palea, widening and obtuse at apex to 1 mm wide, margin erose, paler yellow to white, occasional multicellular hairs present along margins (Fig.2d).

Ray florets female, (1–) 2 or 3 per capitulum, 2–3 (–4) lobed, c. 7 mm long, yellow (Fig.3a); lamina c. 2–3.7 mm long, nerves 5–7; tube constricted below lamina and 1.5 mm long; style exserted from tube; stigma 2-armed; stigma arms c. 0.5–0.75 mm long, papillae absent or reduced; ovary 3 mm long, unilocular with basal placentation. Pappus of 2 stout awns, deflexed and running parallel to cypsela; awns 2.5 mm long.

Disk florets bisexual, 3–6 per capitulum, 4 (–5)-merous, c. 6 mm long, yellow; corolla with dilated apical tube and constricted basal tube; dilated part 1.5 mm long, with lobes free in apical third, free lobes 0.5 mm long, tube 1 mm; constricted basal part 1 mm long; style exserted; stigma 2–armed (Fig.3b). Stigma arms comprised of broadly oblong, receptive surfaces c. 3 mm long, often with a channelled midline visible, which constricts into a linear appendage, c. 0.7 mm long; appendages papillate throughout (Fig.3c). Stamens 4 (–5); anthers connate in tubular sheath around style, opening adaxially, 2 celled, c. 0.8 mm long, base truncate, apex with triangular appendage; filaments free for c. 1 mm and attached to corolla at throat of basal tube. Ovary 3 mm long, unilocular with basal placentation. Pappus of 2 stout awns, deflexed and running parallel to cypsela; awns 2 mm long (shorter than ray floret awns).

Cypsela rod-like, straight, slightly tapering at base and terete to ellipsoid in cross section, 6 –7 mm long x 0.75–1 mm wide, becoming strongly dorso-ventrally flattened at apex, about 0.5–0.8 mm from apex (Fig.3d). Cypsela surface black to reddish brown, finely textured with irregularly protuberances (sclerifications) distributed patchily across the surface; protuberances reddish brown, light brown, fawn or yellow in colour. Cypsela body glabrous or rarely with fine thread-like hairs. Pappus of 2 stout deflexed awns, dorso-ventrally compressed, 0.3–0.4 mm wide, light brown, fawn, yellow, running parallel to body of the cypsela for up to ½ length c. 3.8–4 mm long. Awns retrorsely barbed, hairs about 0.4 mm long; differences in awn lengths observed in flower not obvious in seed.