Marasmodes oubinae, 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-

8. Marasmodes oubinae

S. Ortiz, Bot . J. Linn.Soc. 159: 338 (2009). Type: South Africa. Western Cape, Cape Town (3318): between Malmesbury and Hopefield, near Oude Post (–BC), 24 Apr 1934, Salter 4408 (NBG, holo.; BM, BOL!, K!, iso.).

Marasmodes schlechteri Magee & J.C.Manning, S. A. J. Bot. 76: 280 (2010), syn. nov. Type: South Africa. Western Cape, Clanwilliam (3218): western foot of Piekenierskloof Pass (–DB), 27 May 2009, Magee, Manning & Boatwright 145 (NBG!, holo.; BOL!, K!, PRE!, S!, iso.).

Marasmodes adenosolen auct. non Harv.: Hutch., Bull. Misc. Inform. 1916: 172 (1917).

Well-branched, multistemmed, twiggy shrublets, 0.3–0.6 m tall. Leaves alternate, regularly arranged along branches, spreading, lanceolate to linear or oblanceolate to obovate, 3–10(−12) × 0.5(−5.0) mm, simple or sometimes trifid, mucronulate, secondary basal lobes rudimentary or well developed; axillary fascicles conspicuous. Capitula solitary, on axillary shoots 0.5–4.0(−10) mm long. Involucre obconical, ca. 4–7 × 4–5 mm; bract margins and apices scarious, sessile glands at appendage base inconspicuous, stereome prominent, with upper portion 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, margin and apex very narrowly scarious; inner bracts oblong, ± 4 mm long, margins scarious, apex with a prominent scarious appendage, yellowish brown or reddish pink. Florets ca. 10 to 25; limb 5-lobed from just above midpoint; lobes erect to recurved. Pappus with adaxial scales ±length of corolla tube.

Diagnostic characters

This species shares the relatively large, solitary capitula with obconical to broadly campanulate involucre and involucral bracts with a prominent stereome ( Fig. 7B ) with M. macrocephala . It is distinguished from M. macrocephala by the smaller capitula, 4–5 mm broad (vs 5–7 mm broad in M. macrocephala ), borne on very short lateral shoots, 0.5–4.0 mm long ( Fig. 7A ) (vs. prominent leafy shoots, 5–60 mm long) and the longer pappus which is equal to or longer than the corolla tube (vs pappus equal to half floral tube length).

Ortiz (2009) also included material from the Paardeberg when describing M. oubinae . The Paardeberg specimen(‐s) examined by Ortiz (2009) however, has largely solitary heads and is clearly atypical. Field studies of the Paardeberg population revealed that the capitula are clustered at the branch tips and all the involucral bracts have prominent scarious margins. As such they are very different from the type population of M. oubinae . Rather these traits are diagnostic of M. fasciculata and as a result the Paardeberg material is treated here under the latter.

When describing M. schlechterii, Magee and Manning (2010) had only seen the Paardeberg material and as a result considered M. oubinae to represent a very different taxon with clustered capitula ( Manning and Goldblatt, 2012). Subsequent comparison of M. schlechterii with the type material of M. oubinae has revealed that other than a slight difference in the size of the capitula the two taxa are inseparable and as a result M. schlechterii is here reduced into synonymy.

Distribution and ecology

Historical records indicate that M. oubinae was formerly relatively widespread in shale renosterveld across the northern Swartland between Moorreesburg, the Piketberg and the foot of the Olifants River Mountains ( Fig. 5 ). Less than 10% of shale renosterveld remain in this intensively cultivated area, and the species was not recorded for 50 years until a small subpopulation of about 20 plants was found in 2002 at the foot of the Olifants River Mountains ( Magee and Manning, 2010; Manning and Goldblatt, 2012). At this locality the plants occur on gravelly alluvium in transitional renosterveld–fynbos vegetation together with the endangered Annesorhiza refracta Magee ( Magee et al., 2011), Diplosoma retroversum (Kensit) Schwantes ( Klak et al., 2005) and Oxalis pallens Eckl. & Zeyh. ( Helme et al., 2012).

Despite a recent search the subpopulation at the type locality near Darling could not be relocated and may no longer be extant. Furthermore, it is unlikely that many, if any, subpopulations remain on the lower slopes of the Piketberg due to the extensive transformation of the plains between the Olifants River and Piketberg Mountains (Manning et al., 2012.). CREW recently recorded two subpopulations on small fragments between Eendekuil and the Olifants River Mountains. At these sites, plants were found in renosterveld fragments with quartz gravel. A fourth subpopulation was found near the type locality, at a site earmarked for gravel mining. All four subpopulations are small, the largest with only 35 plants, and three occur on small, isolated renosterveld remnants of less than 25 ha in size. The species is therefore assessed as Critically Endangered, B2ab(iii,v); C2a(i) due to its small Area of Occupancy (<1 km 2), small, severely fragmented population, and ongoing threat of habitat loss and degradation.

Additional specimens examined

3218 (Clanwilliam): Near Eendekuil , western foot of Piekenierskloof Pass (– DB) , 1 Jul 2002, Manning 2747 ( NBG) ; SE end of Piketberg Mountain , stony, clayish lower slopes (–DC/ DD) , 28 May 1952, Esterhuysen 20134 ( BOL, PRE) ; Piketberg, 29 Jun 1896, Schlechter 7899 ( BOL, PRE, Z) . 3318 (Cape Town): Farm Schilpadvalley ( Skilpadvlei ), 3 km east of R45 along R307 , ca. 11 km SW of Moorreesburg, 5 ha remnant of Swartland Shale Renosterveld (– BA) , 21 Apr 2015, Koopman 1237 ( 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. 5. The known geographical distribution of Marasmodes oligocephala (circles), M. oubinae (triangles), M.polycephala (squares) and M. spinosa (diamond).