Marasmodes tri fi da, S. Ortiz, 2009

Magee, A. R., Ebrahim, I., Koopman, R. & von Staden, L., 2017, Marasmodes (Asteraceae, Anthemideae), the most threatened plant genus of the Cape Floristic Region, South Africa: Conservation and taxonomy *, South African Journal of Botany 111, pp. 371-371 : 371-

12. Marasmodes tri fi da . S.Ortiz, Bot. J. Linn. Soc. 159: 331 (2009).

Type: South Africa, Western Cape Province. Cape Town (3318): Groenrivier farm, between the eastern slopes of Dassenberg and Kalabaskraal village , on heavy brackish clay in association with Salicornia (–DA), 2 May 1980, Rourke 1672 (NBG, holo.; K, NBG!, PRE!, iso.).

Weak, single or few-stemmed, sparsely leafy shrublets, 0.3–0.4 m tall. Leaves alternate, restricted to upper branches or branch tips, caducous, suberect to spreading, narrowly obovate, (8)10–14 × 1–4 mm, predominantly apically trifid, some simple or weakly pinnatifid, mucronulate, secondary basal lobes absent; axillary fascicles weakly developed or absent. Capitula mostly solitary, some in irregular clusters of 2 or 3, terminal or on axillary shoots 2–15 mm long. Involucre cylindrical-campanulate, 4–5 × 3–5 mm; bract margins and apices scarious, sessile glands at appendage base inconspicuous, stereome prominent; outer bracts ovate, 1.0– 1.5 mm long, margin and apex not scarious; middle bracts narrowly ovate to oblong, 2.0– 2.5 mm long, margin and apex at most only slightly scarious; inner bracts oblong, 3–4 mm long, narrowly scarious, apex with a prominent scarious appendage, yellowish brown to reddish pink. Florets ca. 10 to 14; limb 5-lobed from midpoint; lobes recurved. Pappus with adaxial scales ≥ length of corolla tube.

Diagnostic characters. The combination of the regularly trifid primary leaves and the single or few stemmed sparsely leafy habit, with the leaves restricted to upper branches or branch tips makes this species easily identifiable. It differs further from M. oligocephala by the longer primary leaves, 10–14 mm long (vs 3–8 mm long) and the absence of prominent scarious margins on the outer and middle involucral bracts.

The weakly branched habit and sparse leaves ( Fig. 7I & J ) is reminiscent of M. defoliata from which it differs by the regularly trifid primary leaves ( Fig. 7J ), the smaller cylindrical-campanulate capitula, 4–5 mm long ( Fig. 7H ) (vs broadly campanulate, 6–10 mm in M. defoliata ) and the longer pappus, equal to or longer than the length of the corolla tube (vs ± half tube length in M. defoliata ).

Distribution and ecology

Marasmodes tri fi da

Is localized to heavy, brackish clay flats in sand fynbos, and since it was first recorded in 1980, it has been only known from a small area between Rondeberg and Kalabaskraal near Malmesbury ( Fig. 6 ). Monitoring of the population at the type locality in the 1980s indicated that the species was formerly abundant at this site, but ongoing habitat degradation, particularly due to the spread of alien invasive wattles, which by now have become an impenetrable thicket, has led to severe decline of this subpopulation over the past 30 years. A few plants persist in a road verge that is frequently cleared of woody vegetation, but there are concerns that frequent mowing is likely to damage the last remaining plants. Three more plants were found on the edge of a nearby clay quarry in 2010, a site that is also densely infested with alien wattles. A single plant was found at a commercial chicken farm in 2011, but at the time of discovery, it had already been sprayed with herbicide intended for clearing alien invasive plants, and later died. M. tri fi da is on the brink of extinction, and is classified as Critically Endangered, C2a(i); D. Urgent conservation interventions are needed to restore the population to viable numbers. A portion of the property at the chicken farm has been set aside for conservation, and M. tri fi da plants are being cultivated ex situ with the intent to reintroduce them to this site.

Additional specimens examined. South Africa. Western Cape: 3318 (Cape Town): Kalbaskraal Nature Reserve (– DA), 26 Apr 1980, Burgers 2360 ( PRE) ; 2 May 1980, Burgers 2368 ( PRE); 27 Apr 2009, Ebrahim CR3768 ( NBG) ; Farm north of Rondeberg turnoff, 1.3 km W of N7 , clay quarry (– DA), 31 Mar 2010, Koopman 976 ( NBG).

Figures

Fig. 7. General morphology of Marasmodes oubinae (A & B), M.polycephala (C & D), M.spinosa (E–G), M. trifida (H–J), M.undulata (K–M).

Fig. 6. The known geographical distribution of Marasmodes oppositifolia (star), M.trifida (circle) and M.undulata (triangle).