Cotula myriophylloides Harv., in Hk., Icon. Pl. 4: 335 (1840) Cotula, L.

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 : 108-109

1. Cotula myriophylloides Harv., in Hk., Icon. Pl. 4: 335 (1840) ,

Harv., in Harv. & Sond., Fl. Cap. 3: 179 (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 Province, Cape Town (3318): Greenpoint, in pools (–CD), Harvey s.n. (TCD lecto. -image!, designated here; K-image!, P-image!, isolecto.).

Floating aquatic annual herb. Stems 40–240 mm long, glabrous, somewhat spongy, 1.5–2.5 mm in diameter. Leaves opposite, spreading, palmatisect, 20–40 × 5.0– 10 mm; base dilated, forming a prominent sheath around the stem, sheath 2.0–3.0 mm long; lobes linear, 20–35 × 0.2–1 mm, ±terete, turgid, dark green, glabrous, apices acute, margins entire. Capitula heterogamous, disciform, solitary, terminal, pedunculate; peduncles glabrous, 20–40 mm. Involucre hemispherical to campaniform, 3.0–5.0 × 3.0– 10 mm, 1-seriate, bracts broadly ovate to broadly elliptic, 2.3–3.0 × 1.0– 2.5 mm, glabrous, green, apex and margins narrowly scarious, three to five veined, secondary venation prominent. Receptacle flat, epalate; pedicels tubiform, 0.3–0.6 mm long, decreasing in length centrifugally, attaching to floret apically. Disciform fl orets female, 3 to 10, in single outer series; corolla absent; style 0.7–0.8 mm long; ovary marginally ribbed, glabrous on inner face; 2 apical appendages present. Disc fl orets bisexual, 25 to 40; corolla 1.5–2.0 mm long, yellow, funnel-shaped tube with basal swelling, longitudinal resin canals present, limb slightly wider than 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 ribbed, glabrous. Cypselas heteromorphic; disciform cypselas ovoid, ca. 1.5 × 0.6 mm, marginally ribbed, with two ovate apical appendages, glabrous; disc cypselas not seen.

Diagnostic characters

4. Key to the species of the Cotula coronopifolia group

The aquatic habit and floating stems of C. myriophylloides render this species unmistakable. It shares the opposite leaves and broadly ovate bracts with the terrestrial C. eckloniana ( Fig. 3A–B ), but can be further distinguished by the uniseriate involucre, tubiform pedicels and the marginally ribbed fruit ( Fig. 4A ) with prominent apical appendages (involucre biseriate, pedicels ovate and fruit marginally winged in C. eckloniana ).

1a Leaves opposite:

2a Leaves palmatisect; involucre 1-seriate; corolla not terminally tailed, and disciform fruit ribbed; floating aquatic .......... ...................................................................................................... 1. C. myriophylloides

2b Leaves entire or pinnate; involucre 2-seriate, inner slightly transparent; corolla terminally tailed, disciform fruit broadly winged; terrestrial............................................................................................ 2. C. eckloniana

1b Leaves alternate:

3a Bracts broadly ovate tapering to obtuse apices:

4a Disc ovaries and fruits marginally winged; corolla tube oblong, limb ± width of tube..................................................................... 3. C. filifolia

4b Disc ovaries and fruits marginally ribbed; corolla tube funnel shaped, limb ± twice width of tube........................................................... 4. C. vulgaris

3b Bracts lanceolate to broadly elliptic, apices obtuse, not tapering:

5a Disc ovaries and fruits marginally winged, with dense terete hairs on inner face.............................................................................................. 5. C. pusilla

5b Disc ovaries and fruits marginally ribbed, glabrous to glabrescent:

6a Leaf bases clasping stem (if bases sheathing, then florets white); leaves regularly pinnate to bipinnate; stems herbaceous, erect or branches spreading, not rooting at the nodes; disciform florets 0 to 14.............................................................................................................. 6. C. bipinnata

6b Leaf bases sheathing fully, florets yellow; leaves simple to apically trifid (occasionally bipinnate); stems thick and spongy, branches decumbent, rooting at the nodes; disciform florets 25 to 30....... ............................................................................................................ 7. C. coronopifolia

Distribution, ecology and conservation status

Cotula myriophylloides occurs in shallow, slow flowing coastal pools or lagoons, often those with a relatively high salinity, and was once apparently common on the Cape Peninsula ( Fig. 5 ) where it is now extinct ( Helme, 2013). Only two isolated and recently discovered populations are known to remain (viz. Bot River Lagoon and De Mond Nature Reserve Lagoon). A single collection of this species at Piesangs River near Knysna suggests that additional possibly overlooked populations between Agulhas and Knysna may still remain. The status of CR B2ab(iii) is retained ( Powell et al., 2013a).

Additional specimens examined

South Africa. WESTERN CAPE: 3318 (Cape Town): Greenpoint (–CD), Schlechter 9023 (PRE), Mac Owen 1170 (BOL). 3418 (Simonstown): Noordhoek saltpan (–AB), Compton 15396 (NBG), Walner 66 (BOL); Kommetjie effluent (–AB), Wolley 3628 (BOL); Submerged in vlei near Maitland (–DA), Stephens 18560 (BOL). 3419 (Caledon): Bot River lagoon, 1.3 km upstream from Klienmond, The Draay 563 (–AC), Helme 5675 (NBG). 3420 (Bredasdorp): 0.1 km south of Vogelgezang farmhouse, west of road to De Mond Nature Reserve (–CA), Helme 5866 (NBG). 3423 (Knysna): Piesangs River, above road bridge (–AB), O'Callaghan 732b (NBG).

Figures

Fig. 3. Bract variation in the Cotula coronopifolia group. (A) C. myriophylloides; (B) C. eckloniana, outer (B1) and inner (B2) bracts; (C) C. vulgaris; (D) C. filifolia; (E) C.pusilla; (F) C. bipinnata; (G) C. coronopifolia.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.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. 5. Known geographical distribution of Cotula myriophylloides.