Cotula duckittiae Levyns
Creators: name: Jakoet, A.
name: Mucina, L.
name: Magee, A. R.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Cotula
Cotula duckittiae

description: 6. Cotula duckittiae (L.Bolus) Levyns, in Adamson & Salter, Fl. Cape Penins. 161 (1950); Bremer & Humphries, Bull. Nat. Hist. Mus. London, Bot. 23: 159 (1993).
Cenia duckittiae L.Bolus, Ann. Bolus Herb. 4: 15 (1925).
Type: South Africa. Western Cape, Malmesbury (3318): Darling (− AD), Sep 1922, C. J. Duckitt 17,184 (BOL, holo.!; K–image!, iso.).
Annual herb, 165–580 mm. Not rooting at the nodes. Stems usually decumbent, 135–283 mm long, sparsely hairy. Leaves alternate, decreasing in length towards upper part of plant, 2- to 3-pinnatisect, 9–72 × 10–19 mm, obovate, green, petiole-like base usually present; lobes linear, 1–6 × 0.4–1.0 mm, ±terete, becoming progressively smaller towards the leaf base, usually downy, apices cuspidate to acute. Capitula heterogamous, 12–22 mm in diameter, disciform, pseudo-radiate, disc face flat to slightly concave, solitary, terminal, pedunculate; peduncles 40–192 mm long, apically swollen in fruit, swelling obconical, 5–18 × 8–15 mm, dark green, hollow. Involucre hemispherical; bracts 2- or 3-seriate; broadly ovate, 3–6 × 3–5 mm, apex obtuse to acute, hairs always present on tips, green, opaque, apex and margins scarious, brownish, 3- to 7-veined. Receptacle flat to shallowly concave. Filiform fl orets female, in single outermost series, pedicellate, corolla absent; ovary elliptic, marginally winged, slightly concave on the ventral surface, glandular; pedicels linear, 1 mm at maturity. Disc fl orets bisexual, heteromorphic, pedicellate, 4-lobed, lobes mostly triangular, ca. 0.2 mm long, florets in two outermost series with the dorsal lobe greatly enlarged to resemble a ray limb, dorsal lobe ±4 times length of other three lobes, elliptic, ca. 2–5 mm long; tube not basally draping over the ovary; limbs funnel- to bell-shaped, usually orange but sometimes canary yellow; pedicels 0.1–0.6 mm long, gradually decreasing in length towards center. Cypselae heteromorphic; those of filiform florets ovoid, 1.6–2.2 × 1.1–1.4 mm, broadly winged, wing ca. ¼ times width of the fertile portion, slightly concave on outer surface, sessile glands present; those of disc florets ovoid, 1.6 × 0.8 mm, marginal ribs prominent, sessile glands present; band of myxogentic cells on ventral surface flanking the fertile portion; resin canals absent.
Diagnostic characters: Cotula duckittiae is unique in that it has large, showy usually orange (rarely canary yellow) pseudo-radiate heads with a flat to concave disc face (Fig.1. K–L) and myxogenic cells flanking the fertile portion on the ventral surface of the disc cypselae (Fig. 3. C 2). The enlarged dorsal lobe of the outer disc florets is significantly larger than in all the other species, ±4 times the length of the other three lobes (Fig. 2. F), and there are often up to two series of these modified disc florets.
Distribution and ecology: Cotula duckittiae is endemic to the West Coast where it occurs scattered from Elandsbaai to Malmesbury (Fig. 9). Populations are highly localized, but locally abundant (Fig. 1. J). It occurs on coarse sand derived from granite. Flowers in spring (September).
Additional specimens examined: South Africa. WESTERN CAPE: 3218 (Clanwilliam): Clanwilliam, Coast S of Elandsbaai, 5.6 km N of Draaihoek Lodge (− AD), 9 Sep 2009, Goldblatt & Porter 13,298 (NBG). 3318 (Cape Town): Farm Rondeberg 10 km SE of Darling (− AD), 13 Sep 1989, Pool 97 (NBG; PRE); West Coast: Rondeberg Nature Reserve (− AD), 25 Aug 2014, Magee & Jakoet 1127 (NBG); Bok Bay, Malmesbury (– CB), 11 Sep 1937, Compton 6780 (NBG); 15 Sep 1940, Kies 154 (NBG); near Leerbaai, ± 2 mls North of Bokbaai (– CB), 20 Sep 1968, Rourke 1115 (NBG; PRE); Buffelsrivier, Malmesbury (– CB), 18 Oct 1962, Taylor 4160 (NBG); 1 km west of Pella (− DA), 31 Aug 1977, Emdon 15 (NBG; PRE). Precise locality unknown: Darling Flower Show, 23 Sep 1950, Maguire 447 (NBG).
description: Published as part of Jakoet, A., Mucina, L. & Magee, A. R., 2019, The pseudo-radiate buttons: A taxonomic revision of the Cotula turbinata group (Asteraceae; Anthemideae) and the description of two new species *, pp. 282-293 in South African Journal of Botany 121 on page 292, DOI: 10.1016/j.sajb.2018.11.016, http://zenodo.org/record/10496566