Cotula discolor (DC.) J.C.Manning & Mucina, S.

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 *, South African Journal of Botany 121, pp. 282-293 : 285-286

1. Cotula discolor (DC.) J.C.Manning & Mucina, S. African J. Bot. 88: 240 (2013).

Cenia discolor DC., Prodr. 6: 82 (1838); Dietrich, Syn. Pl. 4: 1606 (1847).

Cenia sericea var. discolor (DC.) Harv. , in Harvey & Sond., Fl. Cap. 3: 185 (1865).

Type: South Africa, Cap. Bonae-Spei [Cape of Good Hope], s.d., Verreaux s.n. (G-DC 00322967, lecto.–image!, designated by Manning et al., 2013; P –image!, iso.).

Cenia pectinata DC., Prodr. 6: 83 (1838); Dietrich, Syn. Pl. 4: 1607 (1847); Harv., in Harvey & Sond., Fl. Cap. 3: 186 (1865).

Cotula mariae Bremer & Humphries, Bull. Nat. Hist. Mus. London, Bot. 23: 158 (1993) [as a replacement name, non Cotula pectinata Hook.f. ].

Type: South Africa, Eastern Cape, Port Elizabeth (3425): Algoa Bay, Cape Recief (– BA), Feb. 1830, Ecklon s.n. (G-DC, holo.–image!, S –image!, iso.].

Cenia sericea sensu DC. Prodr. 6: 82 (1838), non ( L.f.) Harv., in Harvey & Sond., Fl. Cap. 3: 185 (1865).

Perennial mat-forming herb, 40–410 mm. Not rooting at the nodes. Stems usually erect, 13–211 mm long, mostly hispid. Leaves alternate, length uniform, 2- or 3-pinnatisect, 4–27 × 6–19 mm, oblanceolate to ovate, dark green to silver green, petiole-like base absent; lobes linear, 3–5 × 0.5–2.0 mm, ±terete, occasionally becoming smaller towards the leaf base, sparsely hairy to velvety, apices mucronate to acute. Capitula heterogamous, 7–17 mm in diameter, disciform, pseudo-radiate, disc face convex, solitary, terminal, pedunculate; peduncles 12–143 mm long, apically swollen in fruit, swelling obconical, 2–14 × 3–11 mm, dark green, hollow. Involucre hemispherical; bracts 2- or 3-seriate, broadly ovate, 1.5–3.5 × 1–5 mm, apex obtuse, glabrous, dark green, opaque, apex and margins scarious, brownish, 3- to 5- veined. Receptacle shallowly convex. Filiform fl orets female, in single outermost series, pedicellate; corolla absent; ovary elliptic, marginally winged, slightly concave on the ventral surface, glandular; pedicels linear, pedicels 0.8 mm at maturity. Disc fl orets bisexual, heteromorphic, pedicellate, 4-lobed, lobes mostly triangular, ca. 0.3 mm long, florets in outermost series with the dorsal lobe greatly enlarged to resemble a ray limb, dorsal lobe ±1.5 times length of other three lobes, obovate, 1.5–2.0 mm long; tube not basally draping over ovary; limbs bell- to cup-shaped, yellow; pedicels 0.1–0.4 mm long, gradually decreasing in length towards center. Cypselae heteromorphic; those of filiform florets ovoid, 1.6–1.9 × 1.3–1.5 mm, marginal ribs prominent, wing ca. ⅓ times width of the fertile portion, slightly concave on outer surface, sessile glands present; those of disc florets ovoid, 1.3–1.5 × 0.7–0.9 mm, marginal ribs prominent; sessile glands present, myxogenic cells absent; resin canals absent.

Diagnostic characters: Cotula discolor shares the perennial habit with C. perennans , but can be distinguished by the yellow pseudo-ray florets ( Fig. 2. E ; white in C. perennans ), leaves densely clustered below the peduncle and largely uniform in size (leaves scattered across stem and decreasing in size towards the peduncle in C. perennans ), with subterete leaf lobes (flattened in C. perennans ) and not rooting at the nodes (rooting often occurs at the nodes in C. perennans ).

Distribution and ecology: Cotula discolor occurs along the south coast of South Africa, from Mossel Bay in the Western Cape to East London in the Eastern Cape ( Fig. 4 ). The species occurs in Algoa Dune Strandveld and Albany Dune Strandveld ( Mucina et al., 2006). Flowering is from autumn to early summer (March to November).

Additional specimens examined: South Africa. WESTERN CAPE: 3323 (Willlowmore): South River Mouth, Nature's Valley (–DC), 4 Sep 1981, Parsons 208 ( NBG). 3422 (Mossel Bay): Mossel Bay (− AA), Aug 1912, Rogers 4135 ( NBG); Sedgefield, Buffelsbaai, Rowwehoek, Walker's Bay, at the coast (– BB), 6 May 2006, Mucina 060506/10 ( NBG) 3423 (Knysna): Eastern end of Noetzie beach near Knysna (− AA), 10 Nov 1979, Taylor 10,136 ( NBG); Noetsi River, E side of river (− AA), s.d., O'Callaghan, Fellingham & Van Wyk 45 ( NBG); Keurboomstrand, Knysna (–AB), 4 Jun 1952, Compton 23,604 ( NBG); Robberg Nature Reserve, Plettenberg Bay (–AB), Nov 1923, Smart 27,952 ( NBG); 25 Nov 1994, Watson & Panero 94–99 ( NBG); Tsitsikamma National Park, Storms River Mouth (– BB), 26 Nov 1950, Hall 210 ( NBG); 1 Feb 1965, Middlemont 2284 ( NBG); Tsitsikamma National Park, Kaarlkop, Elandsrivier Mouth (– BB), 1 Jun 2010, Burring s.n. ( NBG); Tsitsikamma National Park, Stormrivier, Otter Trail, close to waterfall (– BB), 26 Apr 2006, Steffen & Kocke S & K 270406/03 ( NBG). EASTERN CAPE: 3227 (East London): East London (− DD), s.d., Bokelmann 6-PL.8 ( NBG); 1 Feb 1957, Taylor 5591 ( NBG). 3326 (Grahamstown): South Coast, Kenton-on-Sea, Diaz Cross, parking lot (− DA), 1 Oct 2001, Mucina 011001/07 C ( NBG). 3424 (Humansdorp): Aasvoëlkrans, east of Oubosstrand, East Tzitzikamma coast (–AB), 10 Mar 1979, Taylor 9968 ( NBG). 3425 (Skoenmakerskop): South Coast, Port Elizabeth, Seaview, on the coast below Seaview Hotel (–AB), 26 Nov 2005, Mucina 261,105/ 09 ( NBG); 26 Nov 2005, 261,105/10 ( NBG); Port Elizabeth, Seaview, coast (–AB), 27 Apr 2001, Mucina 270,401/2 ( NBG).

Figures

Fig. 2. Floret variation and position in the Cotula turbinata group. (A) Diagram representing the positon of the different florets in a typical capitulum, with black circles representing the filiform florets, diamond shape representing the pseudo-ray florets and the white circles representing the disc florets; (B) typical filiform floret from C.pruinosa; (C) typical disc floret from C. duckittiae; (D-I) pseudo-ray florets in C. calcicola (D), C. discolor (E), C. duckittiae (F), C. perennans (G), C. pruinosa (H), and C. turbinata (I). Vouchers: (B) Jakoet & Magee 1111 (NBG); (C) Magee & Jakoet 1127 (NBG); (D) Magee & Jakoet 1138a (NBG); (E) Jakoet 54 (NBG); (F) Magee & Jakoet 1127 (NBG); (G) Esterhuysen 35120 (BOL); (H) Jakoet & Magee 1111 (NBG); (I) Magee & Jakoet 1114 (NBG). Scale: 1 mm.

Fig. 4. Known geographical distribution of Cotula discolor.