Marasmodes crewiana, Magee & I. Ebrahim

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-

1. Marasmodes crewiana

Magee & I.Ebrahim, sp. nov. Type: South Africa. Western Cape, Worcester (3319): Spes Bona Farm, between the Brandvlei and Draaivlei dams near Worcester (–CD), 30 Apr 2013, Magee & Ebrahim 1017 (NBG, holo.!; BOL!, K!, PRE!, NBG!, S!, iso.).

Well-branched, multistemmed, twiggy shrublets, 0.3–0.6 m tall. Leaves alternate, regularly arranged along branches, suberect, linear, 4–10 × 0.5 mm, simple, mucronulate, secondary basal lobes well developed, rudimentary or absent; axillary fascicles absent or rarely poorly developed on old stems. Capitula solitary, terminal or on axillary shoots 5–70 mm long. Involucre obconical to campanulate, 4–5 × 4–6 mm; bract margins and apices scarious, sessile glands at appendage base inconspicuous, stereome obscure; outer bracts broadly ovate, 1.0– 1.5 mm long, margin and apex narrowly scarious; middle bracts ovate, 1.5–2.0 mm long, margins scarious, apex broadly scarious, ± truncate; inner bracts oblong, 2.5–3.5 mm long, margins scarious, apex with a prominent scarious appendage, ovate to broadly ovate, reddish pink. Florets ca. 14 to 36; limb 5-lobed from just above midpoint; lobes erect to recurved. Pappus with adaxial scales ± length of corolla tube.

Diagnostic characters

Marasmodes crewiana and M. undulata

Both have prominent scarious apices on all the involucral bracts. In M. crewiana however the apices of the middle and outer bracts are not extended into ovate or broadly ovate appendages, as in M. undulata , but remain comparatively short and prominently blunt-tipped ( Fig. 2A–C ). Furthermore, the involucre is usually obconical ( Fig. 2A , broadly campanulate in M. undulata ), the involucral bracts have an obscure stereome and the pappus is as long as or longer than the corolla tube (shorter than the corolla tube in M. undulata ).

It has also been confused with Marasmodes macrocephala in the past but can be readily distinguished by the distinctive scarious apices on all the involucral bracts, the absence of a prominent stereome, the shorter leaves, 4–10 mm long (vs 10–18 mm long in M. macrocephala ) and the longer pappus, as long as or longer than the corolla tube (vs more or less equal to half the length of the corolla tube).

Distribution and ecology

The species is known from only two small clumps on adjoining farms between the Brandvlei and Draaivlei dams near Worcester ( Fig. 3 ), where it occurs in and alongside drainage washes in transitional areas between quartzite fynbos and shale renosterveld on lower slopes, together with Cymbopappus adenosolen (Harv.) B.Nord. There are in total fewer than 50 plants, and the population is threatened by ongoing habitat degradation due to erosion caused by livestock grazing, spreading alien invasive plants and too infrequent fire. It is therefore assessed as Critically Endangered according to the criteria C2a(ii); D.

Additional specimens examined

South Africa. WESTERN CAPE: 3319 (Worcester): Draaivlei farm between the Brandvlei and Draaivlei dams near Worcester (–CD), 30 Apr 2013, Magee & Ebrahim 1019 ( NBG, BOL); Hentie De Wet's Farm [Spes Bona], near Villiersdorp, W of the road to Worcester, N of the 27 mile road mark (–CD), 23 Apr 2009, Ebrahim CR 3770 ( NBG, 2 sheets).

Figures

Fig. 2. General morphology of Marasmodes crewiana (A–C), M. defoliata (D & E), M. dummeri (F & G), M. fasciculata (H & I), M. macrocephala (J & K), M. oligocephala (L & M), and M.oppositifolia (O & P).

Fig. 3. The known geographical distribution of Marasmodes crewiana (circle), M. defoliata (square) and M. dummeri (stars).