Cotula calcicola Jakoet, Mucina & Magee, 2019

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 : 289-290

4. Cotula calcicola Jakoet, Mucina & Magee sp. nov. Type: South Africa, Western Cape, Bredasdorp (3420), De Hoop Nature Reserve , road to Koppie Alleen (–BC), 8 Oct 2014, Jakoet & Magee 1138a ( NBG, holo.!; NBG!, PRE!, BOL!, K!, iso.).

Annual erect or sometimes spreading herb, 35–160 mm. Not rooting at the nodes. Stems usually erect, 8–70 mm long, hispid. Leaves alternate, decreasing in length towards upper part of plant, 2- or 3-pinnatisect, 3–14 × 3–8 mm, oblanceolate to obovate, silvery green, petiole-like base occasionally present; lobes linear, 1–3 × 0.3–1.0 mm, ± terete, becoming progressively smaller towards the leaf base, usually hairy, apices acute to mucronate. Capitula heterogamous, 3–9 mm in diameter, disciform, pseudo-radiate, disc face convex, solitary, terminal, pedunculate; peduncles 12–85 mm long, apically swollen in fruit, swelling obconical, 1–6 × 2–4 mm, dark green, hollow. Involucre hemispherical; bracts 2- seriate, broadly ovate, 2–3 × 0.5–3.0 mm, apex obtuse, glabrous, green, opaque, apex and margins scarious, brownish, 3-veined. Receptacle shallowly convex. Filiform fl orets female, in single outermost series, pedicellate; corolla absent; ovary elliptic, broadly winged, deeply concave on ventral surface, mostly glabrous; pedicels linear, 0.4 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 ±2 times length of other three lobes, elliptic, ca. 1.5–2.5 mm long; tube not basally draping over ovary; limbs bell- to cup-shaped, usually white or with those in inner series often yellow; pedicels 0.1–0.2 mm long, disc pedicel length in outermost series 3 times larger than the length of disc pedicel in the center. Cypselae heteromorphic; those of filiform florets ovoid, 1.7–2.2 × 1.3–1.9 mm, very broadly winged, wing ca. 1½ times width of the fertile portion, deeply concave on the outer surface, sessile glands present; those of disc florets ovoid, 0.9–1.5 × 0.4–0.7 mm, marginally ribbed, sessile glands present; myxogenic cells absent or rarely present on the fertile ventral surface; resin canals absent.

Diagnostic characters: Cotula calcicola is a petite, white pseudo-radiate ( Fig. 1. E–H ) annual with relatively large outer cypselae (larger than the involucral bracts; Fig.1. G ). The outer cypselae are conspicuous in that they have thick, very broad marginal wings which are incurved making the outer surface prominently concave ( Fig. 3. A 1 ). This is the smallest species in the group, only 35–160 mm tall, and the only species in the group with the pedicels of the filiform florets prominently longer than the pedicels of the disc florets.

Distribution and ecology: Overberg region (Western Cape Province), especially on Agulhas Plain and in De Hoop Nature Reserve ( Fig. 7 ). It could also be expected on limestone outcrops around De Kelders in the west as far and perhaps as far east as Stillbaai. Cotula calcicola is restricted to calcium-rich sandy-loamy soils (damp in winter and spring) over Bredasdorp limestone. Often occurs in small fissures or soil pockets on limestone pavements, limestone, often in clearings among patches of limestone fynbos and strandveld (e.g. Agulhas Limestone Fynbos, De Hoop Limestone Fynbos; Rebelo et al., 2006). Flowering is usually from mid-winter to early spring (June to September).

Additional specimens examined: South Africa. WESTERN CAPE: 3420 (Bredasdorp): Resiesbaan Siding , 2.5 km E on main road (– AB), 28 Aug 1979, Bohnen 6322 ( NBG) ; Bredasdorp (− AD) , s.d., Schneekluth 115 ( NBG) ; De Hoop , between entrance and village (− AD), 8 Oct 2014, Magee & Jakoet 1131 ( NBG) ; De Hoop, near Opstal, Tierhoek Main Road (− AD), 25 Sep 2013, Mucina 250,913/10 ( NBG) ; De Hoop, Melkkamer (− AD), 20 Sep 1984, Van Wyk 1967 ( NBG) ; De Hoop, Potberg Nature Reserve (− AD), 26 Jul 1979, Burgers 2036 ( NBG) ; De Hoop , seasonally moist area near visitors centre (− AD), 8 Oct 2014, Magee & Jakoet 1135 ( NBG) ; Top of limestone hills, 2.5 km SW of Ouplaas (− AD), 16 Oct 1984, Fellingham 787 ( NBG) ; Potberg , in the lawn at conservation office (– BC), 8 Oct 2014, Magee & Jakoet 1136 ( NBG) ; De Hoop, Witwater , along track (– BD), 18 Sep 1984, Morley 69 ( NBG) ; De Hoop – Witwater (– BD), 6 Aug 1984, Van Wyk 1704 ( NBG) .

Figures

Fig.1. Species of the Cotula turbinata group showing the main diagnostic characters.(A)The multi-nerved broad bracts found in all species in this group (from C.turbinata); (B) C.discolor; (C–D) Cotula turbinata,note the apical swelling of the peduncle;(E–H) Cotula calcicola, note the convex disc face (H) and size of the cypselae in the filiform florets (G); (I) Cotula pruinosa; (J–L) Cotula duckittiae, note the flat to concave disc face and the multiseriate pseudo-rays (K & L).

Fig.3. Cypsela variation in the Cotula turbinata group.(A) C.calcicola: (A1) cypsela of filiform floret; (A2) cypsela of disc floret;(B) C.discolor: (B1) cypsela of filiform floret; (B2) cypsela of disc floret;(C) C.duckittiae: (C1) cypsela of filiform floret;(C2) cypselaof disc floret;(D)C.perennans: (D1) cypsela of filiform floret;(D2) cypsela ofdisc floret;(E) C.pruinosa: (E1) cypsela of filiform floret;(E2) cypsela of disc floret;(F) C.turbinata: (F1) cypsela of filiform floret; (F2)cypsela of disc floret.Vouchers:(A1) & (A2) Magee & Jakoet 1138a (NBG);(B1) &(B2) Jakoet 54 (NBG);(C1) & (C2) Magee & Jakoet 1127 (NBG);(D1) Esterhuysen 33,481 (BOL);(D2) Esterhuysen 33693 (BOL) (E1) & (E2) Magee & Jakoet 1111 (NBG);(F1) & (F2) Magee & Jakoet1114 (NBG).Scale: 1 mm.

Fig. 7. Known geographical distribution of Cotula calcicola.