Achyranthemum recurvatum (L.f.) N.G.Bergh, 2019

Bergh, N. G. & Manning, J. C., 2019, Achyranthemum N. G. Bergh, a new genus segregated from Syncarpha DC. (Asteraceae, Gnaphalieae) *, South African Journal of Botany 125, pp. 434-456 : 446-448

4.3. Achyranthemum recurvatum (L.f.) N.G.Bergh, comb. nov.

Xeranthemum recurvatum L.f., Suppl. Pl.: 366 (1782). Helichrysum (as ‘Elichrysum’) recurvatum (L.f.) Willd., Sp. Pl., ed. 4, 3(3): 1906 (1803). Syncarpha recurvata (L.f.) B.Nord., Comp. Newsl. 17: 6 (1989).

Type: South Africa, Cape of Good Hope, without date or locality, Herb. Bäck ( LINN 990.25, holo.–digital image!)

Low, tangled shrublet to about 0.4 m, branches often trailing, decumbent, forming loose mats, slender, woody, leafless below; young branches densely white-felted, glabrescent. Leaves closely alternate-decussate, sessile and slightly decurrent, stiff and recurved, strongly conduplicate, linear to lanceolate, 10–33 × 3.0– 4.5 mm, pungent, apical mucro ± 1.2 mm long; firm-textured, abaxial surface with very long (2–3 mm or longer) stout silvery-white arachnoid hairs that cohere to form a a thick, longitudinally oriented irregularly reticulating lattice-like sheath, ends of hairs projecting from margins in silky clumps, adaxial surface glabrous or sparsely arachnoid. Capitula terminal, solitary, depressed-globose, 12–14 mm long and (10–)12–15(–18) mm wide, usually distinctly pedunculate, peduncles robust, straight, 5–35 mm long, densely pale-grey felted and bearing one or a few widely spaced, narrow, involucre-like bracteoles; involucral bracts ±70, in ±12 series, outer erect, lanceolate, acute, 7 × 2 mm, stereome small, greenish, bearing white hairs, lamina smooth and dirty-white, middle series erect, subspathulate with acute to obtuse apex, 11 × 3 mm, stereome as in outer bracts, lamina white tinged rose-pink, innermost series erect to cucculate, obovate with obtuse apex, 5–7 × 1.5 mm, white tinged pink. Florets ±60 to 75, yellow, 5.5 × 0.7 mm, lobes erect; anther apical appendage caudiculate. Cypselae ovoid, 3.0 × 1.5 mm, pale brown. Pappus bristles nude at the base where they are united into a smooth ring, otherwise barbellate, apices slender, acute. Flowering time: mainly October–November, but plants can be found in flower in April and other months ( Fig. 5 ).

Distribution and ecology: Highly localised endemic of the Eastern Cape from Hankey to Alexandria, restricted to low-lying areas (from sea level up to 200 m altitude in the Bontveld, a highly restricted vegetation type that covers only 500 km 2 and consists of a mosaic of bushclumps and grassveld. Within the Bontveld, A. recurvatum is confined to shallow calcareous sands on calcrete ridges.

Diagnosis: A highly distinctive species, the only one in the genus with strictly solitary capitula. The relatively small, stiff leaves are strongly recurved, with the adaxial surface ±glabrous while the abaxial surface is covered with long matted hairs, clumps of these hairs projecting from the margins like soft, curled spines. The indumentum appears as a surface layer of silvery tissue that has been reticulately disrupted, and due to clumping the individual hairs are not discernable. In this feature, the leaf indumentum in A. recurvatum is similar to that in A.paniculatum and A. mucronatum .

This is the most morphologically uniform species in the genus. The solitary capitula, usually on long straight peduncles, with pink-tinged involucres, together with the small, recurved leaves, are diagnostic. Achyranthemum recurvatum might be confused with forms of A. sordescens , A. af fi ne and A. argenteum with recurved leaves, but can be distinguished by the leaf indumentum and capitulum characters (see under species descriptions).

Conservation status: This species is listed as Endangered (www. redlist.sanbi.org accessed August 2018). At the time of assessment, eight severely fragmented subpopulations were thought to remain, and these were in decline due to cement mining, urban expansion and alien plant invasion. Exploitation as everlasting cut flowers may also pose a threat in populations that are easily accessible. The plant is rarely collected, being confined to a rare habitat that has come under threat due to habitat transformation, such as the development of the Coega Industrial Zone. A study by Swart (2006) indicated that only four populations remained. Conservation through relocation is the focus of ongoing studies by E. E.Campbell and students at the Nelson Mandela Metropolitan University.

History: Xeranthemum recurvatum was described by Linnaeus f. in 1781 based on an unlocalised specimen in the collection of Abraham Bäck (1713–1795), Swedish physician and close friend of Carl Linnaeus snr. The identity of the species is clear-cut and there are no synonyms.

Additional specimens seen: South Africa. Eastern Cape. –3324 (Steytlerville): Hankey, near Humansdorp , (– DD) , 3 Oct 1966, Bayliss 3605 ( NBG) . – 3325 (Port Elizabeth): Alexandria, Kaba Valley , (– CB) , 23 July 1954, Archibald 5504 ( PRE) ; Uitenhage District, by the Zwartkop River , (– CB) , Nov, Drège 416 ( BOL, SAM) ; Uitenhage, (– CD) , Ecklon & Zeyher 418 ( SAM) ; Cape of Good Hope, Uitenhage , (– CD) , Ecklon & Zeyher PRE 11,967 ( PRE) ; Blue Horizon Bay , (– CD) , 21 May 2002, Potgieter FP00919 ( PRE) ; Grahamstown, Maitland River Mouth , (– CD) , 11 Sept. 1982, Van Jaarsveld 6847C ( NBG) ; Maitlands Forest Reserve , next to footpath on De Stades route, (– CD) , 7 Nov 2009, Weatherall-Thomas CR15098/PEG18 ( NBG) ; road side of fence, 10 km from turnoff from Addo to Centilivers , (– DA) , 12 March 2011, Haiden 5 ( NBG) ; 10 km from turnoff from Addo to Centilevers , roadside of fence, (– DA) , 12 June 2011, Haiden 6 ( NBG) ; between Centlivres and Addo: Windmolen Farm , (– DA) , 29 Sept. 1984, Stirton 10,850 ( PRE) ; Lime Hill on rd. to Addo, ± 500 km 2 around Port Elizabeth, as far as Alexandra ; on road Zwartkops to Addo , 5 mi N of De Rust, (– DA) , 19 Nov 1977, Anderson 4 ( BOL) ; Uitenhage Div., along rd. from Addo to Port Elizabeth , (– DA) 30 Dec 1965, Troughton 223 ( PRE) ; Coega , 7 M. ENE of Coega, (– DC) , 4 March 1948, Acocks 14,054 ( PRE) ; 3.5 MI NE of Coega. (– DC) , 17 March 1954, Acocks 17,621 ( PRE) ; Coega, 2.4 miles from Coega on Grahamstown rd, (– DC) , 17 March 1954, Comins 758 ( PRE) ; Algoa Bay, St. George’ s Strand , (– DC) , 20 Nov 1932, Long 840 ( PRE) ; near Humansdorp, Hankey , (– DD) , 3 Oct 1966, Bayliss 3605 ( NBG) ; Distr. Uitenhague, by the Zwartkop river, amongst shrubs on the Karoolike hills, (– CD) , unknown ( BOL 103120 ) ; – 3326 (Port Elizabeth): Port Elizabeth , 35 miles NE of Coega, (– CA) , 17 March 1954, Acocks 17,621 ( PRE) ; Alexandria, Kaba Valley , (– CB) , 23 July 1954, Archibald 5504 ( PRE) . Without precise locality: Formosa, Lauterwater, Jan 1940, Stokoe s.n. ( SAM 54700 ) ; 1856, de Castelnau 136 ( PRE) ; Ecklon & Zeyher 416 ( BOL, PRE) ; Zeyher s.n. ( SAM 16339 ) ; Zeyher PRE 43,776 ( PRE) ; Van Staden’ s River, Uitenhague, Drège s.n. ( PRE 204291 ) ; South A.recurvatum

Africa, Drège s.n. (BOL); Ecklon & Zeyher s.n. (PRE 204292); Zeyher s.n. (PRE 204290).

Figures

Fig. 5. Achyranthemum recurvatum. A.Habit.B. Leaves. C. Capitulum.D.Leaf indumentum (Haiden 6, NBG).E. Distribution.All photographs N.G. Bergh.