Marasmodes oligocephala, DC., 1838

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-

6. Marasmodes oligocephala

DC., Prodr. 6: 136 (1838); Hutch., Bull. Misc. Inform. 1916: 172 (1917). Marasmodes polycephalus var. oligocephalus (DC.) Harv. in Harv. & Sond., Fl. Cap. 3: 175 (1865). — Type: South Africa. Western Cape, Cape Town (3318): Cape, near Groenkloof (– CB), Apr, Ecklon 867 ( G-DC, image!, holo.) .

Stout, well-branched shrublets, 0.3–0.7 m tall. Leaves alternate, regularly arranged along branches, spreading to reflexed, narrowly lanceolate to linear or oblanceolate, 3–8 × 0.5–3.0 mm, simple or sometimes trifid, mucronulate, secondary basal lobes rudimentary or well developed; axillary fascicles present. Capitula mostly solitary, some in irregular clusters of 2(3), terminal or on axillary shoots 2–12 mm long. Involucre cylindrical-campanulate, 3–4 × 2–3 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 broadly scarious; middle bracts narrowly ovate to oblong, 1.5–2.0 mm long, margin broadly scarious, apex with a scarious appendage; inner bracts oblong, 2.0– 2.5 mm long, margins scarious, apex with a prominent scarious appendage, yellowish brown. Florets ca. 6 to 10; limb 5-lobed from just above midpoint; lobes recurved. Pappus with adaxial scales ±length of corolla tube.

Diagnostic characters

This species shares the mostly solitary, cylindrical-campanulate heads with M. tri fi da but can be distinguished by the primary leaves which are shorter, 3–8 mm long, and predominantly simple (vs (8) 10–14 mm long and predominantly trifid in M. tri fi da), the stoutly branched, densely leafy habit with the leaves regularly arranged along branches ( Fig. 2L ), (vs weak, single or few-stemmed, sparsely leafy shrublets with leaves restricted to upper branches or branch tips in M. tri fi da) and the involucral bracts which all have broad scarious margins (vs broadly scarious on the inner bracts only in M. tri fi da).

Marasmodes oligocephala is easily confused with M. fasciculata but can be distinguished by the smaller cylindrical-campanulate heads, 2–3 mm broad (vs campanulate or narrowly obconical, 3–5 mm broad), which are mostly solitary or with some in irregular clusters of 2(3) along the upper parts of the stem ( Fig. 2M ) (vs regular terminal clusters of 2 to 8).

Distribution and ecology

The species is restricted to silcrete outcrops in shale renosterveld between Atlantis and Malmesbury ( Fig. 5 ), a habitat of which less than 10% remains after extensive loss to crop cultivation. Much confusion about the identity of M. oligocephala has limited conservation efforts in the past. Hall and Veldhuis (1985) thought the species had a wide distribution range, including many collections that Ortiz (2009) later separated as belonging to other species. Hall and Veldhuis (1985) suspected that it may be in danger of extinction as many populations on the Cape's western coastal lowlands were known to have been severely reduced through habitat loss. Raimondo et al. (2009), included records now recognised as M. tri fi da in their assessment, mistakenly assuming that the species is protected in the Kalbaskraal Nature Reserve. Our revision of the material revealed M. oligocephala to be limited to a very small area (Extent of Occurrence 7 km 2). Recent collections indicate that there are four remaining subpopulations, all occurring on small renosterveld remnants. At two of these fragments, the species is fairly common, with around 200 plants occurring at each. A third subpopulation is very small, consisting of about 10 plants. The fourth subpopulation was last observed in 2006, and the number of plants was not counted. This subpopulation occurs on a tiny fragment of about 2 ha, and is unlikely to be large. It is therefore estimated that the species has fewer than 500 mature individuals remaining in the wild, and continues to decline due to ongoing habitat loss and degradation. It is therefore classified as Endangered according to the criteria B1ab(iii,v) + 2ab(iii,v); C2a(i).

Additional specimens examined

South Africa. WESTERN CAPE: 3318 (Cape Town): Malmesbury, 7 km E of Atlantis , W of N7 on Zouterivier 22, 1 km NW of Rondeberg farmhouse (– DA), 12 Feb 2002, Helme 2490 ( NBG) ; 26 May 2006, Walton 369 ( NBG) ; N7 , E side of road, just S of Rondeberg turnoff near Zoutrivier (– DA), 26 May 2006, Walton 369B ( NBG) ; Atlantis, Rondeberg road off N7 , Kora homestead (– DA), 19 May 2009, Cowell et al. MSBP3984 ( NBG) ; Schoongezicht, near Riverlands (– DA), 22 Apr 1992, Daines 932 ( BOL ); 27 Apr 2009, Ebrahim CR3769 ( NBG) ; 1 Jun 2012, Magee 495 ( NBG) ; 7 Jun 2013, Hutchinson et al. MSBP 4877 ( NBG) ; Three Fountains farm (– DA), 1 Jun 2012, Magee 497 ( NBG) .

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. 5. The known geographical distribution of Marasmodes oligocephala (circles), M. oubinae (triangles), M.polycephala (squares) and M. spinosa (diamond).