Cotula pusilla Thunb., Fl. Cap.

Powell, R. F., Boatwright, J. S. & Magee, A. R., 2014, A taxonomic revision of the Cotula coronopifolia group (Asteraceae) and implications for the conservation statuses of the species *, South African Journal of Botany 93, pp. 105-117 : 112-113

5. Cotula pusilla Thunb., Fl. Cap. 695 (1823);

DC., Prodr. 78 (1838); Spreng., in Linn., Syst. Veg 3: 498 (1826); Harv., Harv. & Sond., Fl. Cap. 3: 178 (1865); Levyns, in Adamson & Salter, Fl. Cap. Penins. 162 (1950); Goldblatt & Manning, Cape Pl.: 366 (2000); Manning & Goldblatt, Pl. Gr. C.F.R. 366 (2012).

Type: South Africa. Western Cape, (3318) ‘Swartlandiae’ Thunberg s.n. sub THUNB-UPS 20225 (UPS, lecto. image,!, designated here).

Upright, annual herb. Stems 5–15 mm, glabrous, herbaceous, 0.5–1.5 mm wide. Leaves alternate, spreading, ±terete, entire, once-pinnate or twice-pinnate, 6.0–35 × 2.0–6.0 mm; base dilated, forming a prominent sheath around the stem, sheath 1.0–4.0 mm long; lobes linear to ovate, 0.3–2.0 × 0.1–2.0 mm, flat, leathery, light to dark green, densely to sparsely hairy, apices acute, margins entire. Capitula heterogamous, disciform, solitary, terminal, pedunculate, peduncles glabrous to sparsely hairy, 5.0–15.0 mm. Involucre hemispherical, 2.0–6.0 × 3.0–9.0 mm, 1-seriate, bracts broadly elliptic, 2.0–4.0 × 1.0–2.0 mm, glabrous, purplish, opaque, apex and margins scarious, distinctly three veined, secondary venation obscure. Receptacle flat, epaleate; disciform pedicels linear, 0.15–1.0 mm at anthesis, uniform, pedicel attaching to floret apically. Disciform fl orets female, ca.4 to 6, in single outer series, corolla absent, style 0.45–0.6 mm, ovary marginally winged, with dense terete hairs on inner face. Disc fl orets bisexual, ca. 20 to 40, corolla 1.2–1.5 mm long, whitish, oblong, tube draped basally over ovary apex, longitudinal resin canals sometimes present, limb same width as tube, 4 lobed; lobes triangular, upright to spreading, dorsally tuburculate, glandular; anthers 0.5–1.2 mm long (including apical appendages), ecaudate, apical appendages ovate, acute; style terete with thickened base; branches truncate, papillate apically-dorsally; ovary marginally winged, dense terete hairs on inner face. Cypselas heteromorphic; disciform cypselas ovoid, ca. 1.7 × 1.4 mm, marginally winged, ±equal to width of ovary, base cordate, inner face with dense terete hairs; disc cypselas ovoid, ca. 1.2 × 0.6, marginally winged, wing width equal to ovary, with dense terete hairs.

Diagnostic characters

Cotula pusilla may be readily confused with the southern populations of C. bipinnata with which it shares the white florets ( Fig. 1.I and K ), but can be distinguished by the broadly elliptic bracts (oblong in C. bipinnata ), the marginally winged disc ovaries and the dense terete hairs on the inner face ( Fig. 4.E ) of both the disciform and disc ovaries (marginally ribbed and glabrous in C. bipinnata ).

Distribution, ecology and conservation status

Cotula pusilla is a widespread but localised habitat specialist occurring from Clanwilliam along the West Coast to the Cape Flats and Caledon ( Fig. 9 ). It is found on the margins of seasonal saline pools in sandy coastal areas and as a result of agricultural expansion, the remaining subpopulations are largely confined to isolated fragments among crop fields. The conservation status of the species has been upgraded to VU B2ab(i,ii,iii,iv,v) and it is threatened by further habitat loss due to agricultural and urban expansion ( Powell et al., 2013e).

Additional specimens examined

South Africa. WESTERN CAPE: 3217 (Vredenburg): West Coast, Vredenburg, at road to Jacobsbaai (–DD), Mucina & Jakubowsky 040806/21 (NBG). 3218 (Clanwilliam): Zeekoei Vlei (–BA), Schlechter 8582 (BOL); West Coast, Sandveld, road Velddrif to Piketberg, Tasaars Kuil Farm (–CD), Mucina & Jakubowsky 040806/31 (NBG). 3318 (Cape Town): West Coast, Darling, road between Malmesbury and Darling, near Wylands (–AD), Mucina & Jakubowsky 040806/04A (NBG); Porterville (–BB), Schlechter 4883 (BOL); Green Point, Cape Town (–CD), Thode 585 (NBG), Ecklon & Zeyher 38779 (SAM); Claremont (–CD), Schlechter 1066 (BOL); Three Anchor Bay (–CD); Wolley 7253 (BOL), Robben Island (–CD), R.S.A. s.n. (BOL); Intaka Island (–CD), Magee & Powell 1029 (NBG). 3321 (Ladismith): Muiskraal (–CC), Bolus 11320 (BOL). 3419 (Caledon): Caledon, 1 km South of Caledon, just east of rifle range and cemetery (–AB), Helme 2332 (NBG); Overberg region, Fairfield farm, stop 3 (–BD), Walton 462 (NBG).

Figures

Fig.1. The species of the Cotula coronopifolia group.(A) C.myriophylloides in flower at the Bot River Lagoon (N.Helme); (B–D) C.eckloniana, note the flat topped capitula andcharacteristic biseriate bracts,with the inner series translucent (E) corolla of C.eckloniana in dorsal view,ventral view (with andwithout ovary,note apical pouch) and side view(note tail-like extended corolla base; (F–G) C.vulgaris; (H) C.filifolia; (I) white-flowered C.bipinnata; (J) yellow-flowered C. bipinnata (K–L) C.pusilla; (M) C.coronopifolia, note the rooting at the nodes.

Fig.4.Floret variation showing the disciform and disc floret of each species in the Cotulacoronopifolia group.(A) C.myriophylloides: (A1) disciform floret;(A2) disc floret;(B) C.eckloniana: (B1) disciform floret,(B2) disc floret dorsal view,(B3) disc floret ventral view with ovary,(B4) disc floret ventral view without ovary; (C) C.vulgaris: (C1) disciform floret,(C2) disc floret; (D) C.fililfolia: (D1) disciform floret, (D2) disc floret; (E) C.pusilla: (E1) disciform floret, (E2) disc floret; (F) C.bipinnata: (F1) disciform floret, (F2) disc floret; (G) C.coronopifolia: (G1) disciform floret, (G2) disc floret. Vouchers: (A) Compton 15396 (NBG); (B) Mucina & Jakubowsky 040606/12 (NBG); (C) Gubb 76 (NBG); (D) Helme 3483 (NBG);(E) Jakubowsky 1/2007 (NBG); (F) Compton 11632 (NBG); (G) Oliver, TÖlken & Venter 313 (NBG).Scale = 1 mm. Artist R.F.Powell.

Fig. 9. Known geographical distribution of Cotula pusilla.