Marasmodes macrocephala S. Ortiz 2009
Creators: name: Magee, A. R.
name: Ebrahim, I.
name: Koopman, R.
name: von Staden, L.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Marasmodes
Marasmodes macrocephala

description: 5. Marasmodes macrocephala
S.Ortiz, Bot. J.Linn. Soc. 159: 338 (2009). Type: South Africa. Western Cape, Worcester (3319): in convalle Hex River, prope De Doorns (–BC), Apr 1907, Bolus 13126 (BOL, holo.; BM, BOL!, K, iso).
Well-branched, multistemmed, twiggy shrublets, 0.3–0.6 m tall. Leaves alternate, those on axillary flowering shoots opposite to subopposite, regularly arranged along branches, suberect to spreading, linear to oblanceolate, 10–18 × 0.5 mm, simple or rarely with 1 or 2 lateral lobes, mucronulate, secondary basal lobes rudimentary; axillary fascicles developed into flowering shoots. Capitula solitary, on axillary shoots 5–60 mm long, sometimes less than 3 mm long near the branch tips. Involucre campanulate to obconical, 5–7 × 5–7 mm; bract margins and apices scarious, sessile glands at appendage base inconspicuous, stereome prominent, conspicuously green-flanked; outer bracts ovate, 1.5–2.5 mm long, margin and apex very narrowly scarious; middle bracts narrowly ovate, 3.0– 3.5 mm long, margins and apex very narrowly scarious; inner bracts oblong, 4.5–5.0 mm long, margins narrowly scarious, apex with a prominent scarious appendage, yellowish brown. Florets ca. 16 to 25; limb 5-lobed from midpoint; lobes recurved. Pappus with adaxial scales ±half length of corolla tube.
Diagnostic characters
M. macrocephala and M. oubinae
Share the relatively large, solitary capitula with obconical to broadly campanulate involucre, 5–7 mm wide and involucral bracts with a prominent stereome. It can however be distinguished by the capitula which are borne on prominent leafy shoots, 5–60 mm long (Fig. 2J & K; vs very short lateral shoots, 0.5–4.0 mm long in M. oubinae) and the short pappus, extending only halfway up the corolla tube (vs pappus equal to or longer than tube). The involucre of M. macrocephala is also somewhat larger, 5–7 mm broad (vs 4–5 mm in M. oubinae).
Distribution and ecology
The species occurs on seasonally wet patches between Wolseley and De Doorns (Fig. 4). Ortiz (2009) described this species from a single collection from the Hex River Valley in De Doorns dating from 1907. As this area is almost completely transformed to vineyards, the species was initially thought to be extinct, until CREW members found a small subpopulation of about 200 plants on a commonage on the edge of Wolseley in the Breede River Valley in 2010, and in 2013, another, even smaller subpopulation of 15 plants was found about 2 km away on the opposite side of the town. At both these sites it occurs in seasonally wet transitional areas between shale renosterveld and Breede Alluvium Fynbos, which is also present in the Hex River Valley, and of which less than 40% remains intact (Table 2). The Breede and Hex River valleys are some of South Africa's foremost wine production regions, and valley-bottom alluvial soils are most intensively cultivated. There is ongoing pressure of agricultural expansion on remaining lowland alluvial fynbos fragments, as well as urban expansion around growing towns in this region.
The Wolseley commonage site burnt in the summer of 2013. When surveyed the following year (May 2014) the mature plants of this species had been killed in the fire but the subpopulation had reseeded and most of the plants were already flowering. At that time the subpopulation size was estimated to be less than 200 individuals. The species is therefore assessed as Critically Endangered, C2a(ii), due to the small number of plants remaining in the wild, of which more than 90% occur in one subpopulation that is threatened by spreading alien invasive plants and urban expansion. Surveys of the remaining alluvial fynbos-renosterveld fragments in the Hex River Valley are still needed to confirm whether any extant subpopulations remain in this area.
Additional specimens examined
South Africa. WESTERN CAPE: 3319 (Worcester): Wolseley commonage NW of town (– AC), 27 Apr 2010, Koopman CR6067 (NBG); 9 Jul 2012, Magee & Koopman 500 (NBG); near Wolseley cemetery (– AC), 22 May 2013, Koopman 1032 (NBG).
description: Published as part of 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 *, pp. 371 in South African Journal of Botany 111 on page 371, DOI: 10.1016/j.sajb.2017.04.006, http://zenodo.org/record/10496420