A taxonomic revision of the Cotula coronopifolia group (Asteraceae) and implications for the conservation statuses of the species *
Author
Powell, R. F.
Author
Boatwright, J. S.
Author
Magee, A. R.
text
South African Journal of Botany
2014
2014-07-31
93
105
117
http://dx.doi.org/10.1016/j.sajb.2014.03.008
journal article
10.1016/j.sajb.2014.03.008
1727-9321
10496967
3.
Cotula
fi
lifolia Thunb., Fl. Cap. 695 (1823)
;
Spreng., in Linn., Syst.Veg 3: 497 (1826); DC. Prodr. 77 (1838); 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
,
Cape
Town (3318): Zoutrivier (–CD),
Thunberg s.n. sub THUNB-UPS 20219
(UPS, lecto. -image!, designated here).
Upright annual herb.
Stems
30–150 mm
, glabrous, herbaceous,
0.5–1.5 mm
wide.
Leaves
alternate, spreading, entire, sometimes once-pinnate, 0.5–25.0 × 1.0–2.0 mm, base dilated, forming a prominent sheath around the stem, sheath 1.0–3.0 mm long; lobes linear, 0.5–25 × 1.0–
1.8 mm
, ±terete, leathery, dark green, glabrous, apices acute, margins entire.
Capitula
heterogamous, disciform, solitary, terminal, pedunculate peduncle glabrous to sparsely hairy, 30.0–75.0 mm.
Involucre
hemispherical, 3.0–6.0 × 4.0–6.0 mm, 1-seriate, bracts broadly ovate tapering to an obtuse apex, 2.0–5.0 × 2.0–4.0 mm, glabrous, green, opaque, apex and margin scarious, four to six veined, secondary venation prominent.
Receptacle
flat, epaleate; pedicels linear, pedicels 0.4–2.0 mm at anthesis, uniform, attaching to floret apically.
Disciform
fl
orets
female, ca. 6, in single outer series, corolla absent, style
0.2 mm
, ovary marginally winged, usually with stout flat hairs on inner face.
Disc
fl
orets
bisexual, ca. 20 to 40, corolla
0.95–1.1 mm
long, yellow, oblong, tube not draped basally over ovary apex, longitudinal resin canals present, limb slightly wider than tube, 4 lobed; lobes triangular, upright to spreading, dorsally tuberculate, slightly 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, usually with stout flat hairs on inner face.
Cypselas
heteromorphic; disciform cypselas ovoid, ca. 1.4 × 1.0 mm, marginally winged, wing ½ width of ovary, base cordate, inner face usually with stout flat hairs on inner face; disc cypselas ovoid, ca. 1.6 ×
0.9 mm
, marginally winged, wing ⅓ width of ovary, inner face usually with stout flat hairs.
Diagnostic characters
Cotula
fi
lifolia
has in the past often been confused with
C. vulgaris
, with which it shares the usually entire leaves and broadly ovate bracts (
Fig. 2.C–D
and
Fig. 3.C–D
). It is, however, readily distinguished by the marginally winged disc ovaries (
Fig. 4.D
2
) and fruit with stout hairs (marginally ribbed and glabrous in
C. vulgaris
) and the smaller oblong disc florets with a limb that is only slightly wider than the tube (campanulate and limb ± twice as wide as tube in
C. vulgaris
).
C.
fi
lifolia
is also generally smaller and more slender and appears to flower earlier than
C. vulgaris
where they co-occur.
Distribution, ecology and conservation status
Cotula
fi
lifolia
is a widespread but localised habitat specialist, common on the
Cape
West Coast (
Fig. 7
). It is found in marshy areas, damp places and freshwater pool margins, often with
C. vulgaris
. Subpopulations on the
Cape
Peninsula have shown a great decline, with many subpopulations now locally extinct as a result of habitat loss to urban expansion. This species has been downgraded to NT B2ab(ii,iii,iv,v) (
Powell et al., 2013c
), and is still threatened by habitat loss due to coastal development, agricultural expansion and alien invasive species.
Fig. 7.
Known geographical distribution of
Cotula
fi
lifolia
.
Additional specimens examined
South Africa
.
NORTHERN CAPE
:
3017 (Hondeklipbaai):
Namaqualand, Hondeklipbaai (–AD),
Mucina & Jakubowsky 040906/08
(NBG).
WESTERN CAPE
:
3217 (Vredenburg):
Vredenburg, southern edge of Paternoster, near Lizaseklip (–DD),
Helme 3483
(NBG).
3218 (Clanwilliam):
Berg River, Veldrif (–CC),
Hugo 2972
(NBG),
Magee
,
Powell & Boatwright 1026
(NBG); ±
5 km
S of
St. Helena
, pan just west of Langeklip Farm (–CC),
Helme 562
(NBG).
3318 (Cape Town):
Yzerfontein, Skaapeiland, Wanderpad (–AC),
Mucina & Jakubowsky 040806/14
(NBG); Darling, Tiene Versveld Flower Reserve (–AD),
Mucina & Jakubowsky 040806/10
(NBG),
Magee
,
Powell & Boatwright 1022
(NBG); Northern part of Paarden-eiland, small dune south of mouth of Jakkals River (–CD),
TÖlken 80
(NBG). Paarden Island (–CD),
Salter 7444
(BOL); Pools around Cape Town (–CD),
MacOwen 3097
(SAM); Salt River (–CD),
Ecklon & Zeyher 838
(SAM); Green Point (–CD),
Ecklon & Zeyher 38779
(SAM).
3418 (Simonstown):
Little Lion's head (–AB),
Stokoe 63990
(SAM); Chapman's Peak (–AB),
Esterhuysen 23969
(BOL); Kommetjie (–AB),
Adamson 7309
(BOL).
3419 (Caledon):
South Coast, Stanford, De Kelders (–CB),
Mucina 100906/07B
(NBG); Overberg, Gansbaai, Uilkraalsmond Estuary (–CB),
Mucina 100906/10
(NBG); Uilkraals River, N bank of river
1.5 km
from bridge (–CB),
O'Callaghan 6/8/14
(NBG).
3420 (Bredasdorp):
Cape Agulhas (–CC),
Salter 4821
(BOL).