Achyranthemum paniculatum (L.) 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 : 440-443

4.1. Achyranthemum paniculatum (L.) N.G.Bergh, comb. nov.

Xeranthemum paniculatum L., Sp. Pl. 2:859 (1753). Helichrysum [as ‘ Elichrysum ’] paniculatum (L.) Willd., Sp. Pl., ed. 4, 3(3): 1911 (1803). Syncarpha paniculata (L.) B.Nord. in Comp. Newsl. 17: 6 (1989). Type: South Africa, specimen illustrated in Burm., Rar. Afr. Pl., t.67, f.1. ( G 00804728 , lecto.–digital image!, designated by Hilliard & Burtt: 250 [1981a])

Xeranthemum paniculatum var. β Lam., Encycl. 3: 241 (1786), nom. inval. Helichrysum intermedium Less., Syn. Gen. Compos. : 295 (1832). Helichrysum paniculatum var. intermedium (Less.) Harv. in Fl. Cap.: 226 (1865). Type: South Africa, Cape of Good Hope (P-LAM P00342667, holo.–digital image!).

Xeranthemum angustifolium Lam., Encycl. 3: 241 (1786). Type: South Africa, Cape of Good Hope (P-LAM P00342664 , holo.– digital image!).

Helichrysum paniculatum var angustifolium Harv. in Fl. Cap. 3: 226 (1865). Type: not designated.

Anaxeton racemosum Schrank, Denkschriften der KÖniglichen Akademie der Wissenschaften zu München 8: 163 (1824). Helichrysum mucronatum var. niveum DC. :178 (1838), as a new name at varietal rank for A. racemosum Schrank. Type: South Africa, ‘Cap. b. sp.’, without date, Brehm s.n. (M 0104887, holo.–digital image!).

[ Gnaphalium racemosum Schrank ms (written on type specimen of Anaxeton racemosum Schrank )].

Low, sparsely branched subshrub, usually 0.2–0.7 m high but up to 1.2 m, woody below, branching mostly near base, stems simple or sparsely branched above, grey-felted. Leaves alternate, laxly to densely imbricate, sessile, basal portion apressed and attached to stem with a reticulate, sheath-like webbing of white hairs; distal portion erect to spreading, sometimes incurved or apically recurved, linear to linear-subulate, extremely variable in size, 10–25(–65) mm long × 0.8–3.0 (–5.0) mm wide, concave or conduplicate, striate, margins narrowly involute,apex usually with a triangular mucro ± 1.2 mm long, sometimes pungent, firm-textured, both surfaces with very long (2–3 mm or longer) silvery-white arachnoid hairs that cohere to form a a thick, longitudinally oriented irregularly reticulating lattice-like sheath, indumentum less developed and more compact on the concave adaxial surface, strongly developed abaxially particularly on the apical portion of leaf. Capitula (1–) 3 to 15(–40) in a compact pseudo-corymb, spherical, 6–15 × 6–18 mm, peduncles slender, 5–45 mm long, densely pale grey-felted with thick layer of very fine interwoven whitish hairs. Involucral bracts ±60 to 120, in ±6 to 9 series, lamina white, frequently tinged pink when immature; outermost bracts erect or squarrose at maturity, broadly lanceolate, 4–8 × 2–3 mm, stereome with long white hairs abaxially, lamina acute, silvery-white, somewhat keeled, middle bracts mostly squarrose, linear-lanceolate to narrowly oblanceolate, 5–12 × 2.5–3.0 mm, stereome 2.0–3.0 mm long, innermost bracts erect, 4.0–6.0 × 0.5–1.2 mm, stereome linear, 4.0–4.5 × 0.8–1.0 mm, with patch of long, tangled white hairs on abaxial apex, lamina as in outer bracts but short, deltoid, obtuse,1.5–2.0 × 1.2 mm. Receptacle 4.0–5.0 mm in diameter. Florets ±(25–)40 to 120, corolla not or very slightly and gradually expanded apically, yellow, 4.5–6.5 × 0.3–0.5 mm including lobes; anther apical appendage acuminate to caudiculate. Cypselae linear, 1.2 × 0.4 mm, dark reddish-brown. Pappus bristles united at base into a smooth ring, shaft barbellate, apex nude but apical cells inflated distally forming acute, barb-like projections. Flowering time: mainly September–December, into January at high alittude, rarely February and May–July ( Fig. 3 ).

Distribution and ecology: The most widespread member of the genus, occurring on the drier margins of the fynbos on quartzitic mountain slopes, from the northern Cederberg, Cold Bokkeveld and Swartruggens and the Touwsberg and Witteberg regions, and further south from Hangklip in the Kogelberg region and the Houw Hoek mountains near Elgin eastwards along the southern coastal mountains to the Langeberg, and at lower altitude along the coastal regions from Albertinia to Knysna , with a few poorly specified collections from the Port Elizabeth area and one from Coombs near Grahamstown (Bayliss 4366 [NBG]). Although this last collection represents a strong disjunction, there is no reason to doubt the locality, since Bayliss was based in the area. The apparent disjunction may be explained by the plants being very rare east of Port Elizabeth, where it is replaced by other species. With the exception of the Potberg sandstone inselberg, A. paniculatum is absent from the Agulhas plain region, being replaced here by A. mucronatum .

Note: Achyranthemum paniculatum and A. mucronatum form a taxonomically difficult species complex, as indicated by the large number of described species and varieties. Within this complex, there is a large range of variation in sizes of both floral and vegetative features. At one extreme, specimens are robus with broad leaves and large heads borne in large numbers on each flowering shoot. At the other extreme are smaller, more slender specimens with very narrow leaves and small, few-flowered heads generally borne in small synflorescences. Specimens at the two extremes are quite distinct, and would be considered separate species without appreciation of the full range of variation. However, examination of all available specimens, coupled with measurements of leaf, peduncle, capitulum and floret dimensions, and counts of numbers of capitula per flowering shoot, numbers of involucral bracts, and numbers of florets per capitulum, indicate that it is not possible to discriminate discrete entities using quantitative criteria. Most specimens combine contrasting characters (e.g. broad leaves with small heads) or are intermediate in all or some of the characters. However, involucral bract colour (yellow vs. white) reliably segregates the specimens into two groups that also show distinct ecologies. Plants with yellow bracts are confined to calcrete substrata in the Bredasdorp– Riversdale area, a region known for high endemism strongly linked to edaphic specialisation ( Cowling and Holmes, 1992). In contrast, plants with white bracts are distributed on quartzite-derived substrata throughout the western part of the Core CFR. Within each of these two entities, the full range of variation described above can be seen, and the variation appears to have a geographical component (see below under ‘Variation’, and further comments under A. mucronatum ).

Diagnosis: Achyranthemum paniculatum is distinguished from other species in the genus by the combination of white bracts, linear to linear-subulate leaves tapering to an acute apex, and a leaf indumentum comprising a fine woolly layer beneath a silvery-white, tissue-like layer fraying to form a covering identical to a layer of stout, striate-reticulate hairs, often confined to the apical portion of the leaf. Achyranthemum paniculatum is most likely to be confused with A. mucronatum , from which it is distinguished by white rather than yellow involucral bracts and by distribution, with A. mucronatum being confined to calcrete or mixed calcrete habitats in the Agulhas plain area, although the two species co-occur in the Potberg region (see further discussion under that species). It is also easily confused with A. argenteum , especially when specimens of the latter have immature heads, but is distinguishable by its smaller heads (6–15 × 6–18 mm vs. 12–18 × 10–18 mm in A. argenteum ) and leaf indumentum. In A. argenteum , the individual hairs of the tomentum are much finer and shorter, so that the texture of the leaf surface is visible, which is not the case in A. paniculatum where the hairs are robust and thick, completely obscuring the leaf texture and creating silvery longitundinally reticulating striations. The two species also differ in leaf shape, the leaves being widest in the upper half and with a hooked apex in A. argenteum , and generally linear to linear-subulate and broadest at the base in A. paniculatum . Additionally, A. argenteum is confined to coastal dune habitats in the Port Elizabeth region, while A. paniculatum is widespread throughout the CFR and is generally found in montane sandstone habitats. Specimens of A. paniculatum from the northwestern and central parts of the range (Cederberg to Witteberg through the Little Karoo to the Langeberg and Outeniquas) have the (mostly inner) involucral bracts flushed pink in bud, fading to white on maturity. Immature specimens can thus be confused with A. af fi ne, but in that species the pink flush is always on the outer involucral bracts and does not fade as the capitula mature, and the reticulating hair-sheath on the leaf is very thin and fine, not thick with robust clumps of hairs as in A. paniculatum .

Variation: The strongest distinction within the species is between gracile plants with very slender leaves and small, fewer-flowered heads held in few-headed synflorescences, and more robust plants with large, broad leaves and large, many-flowered heads in many-headed synflorescences. Specimens representing the extremes of these two forms were previously recognised as different species, with some of the intermediates also being given species status. Characters such as leaf width and capitulum size and number, however, A. paniculatum vary independently across the range, possibly being correlated to moisture availability and temperature, providing no basis for subdivision of the species into slender and robust forms. Coastal specimens from the Knysna district (quarter-degree squares 3423AA and 3423AB) are very distinctive, and this warrants future investigation (see below).

Gifberg to Cederberg: Plants are compact with narrow leaves and rather small heads, borne in groups of 3–10 or more per flowering shoot, although some specimens from the Pakhuis area have a solitary head terminating some of their flowering shoots, but up to six per flowering shoot in the same gathering (e.g. Leipoldt 3624 [NBG]). Plants from the central Cederberg ( Algeria and Uitkyk), in contrast, are characterised by extremely large, long leaves and larger heads borne in larger groups (of up to 30). Plants from the Wupperthal and Citrusdal regions may be similar to either of these two forms.

Ceres to Witteberg: Plants from the Swartruggens region, the mountains northeast of Ceres , and the Witteberge have just one or two (rarely up to five) large to medium-sized heads (to c. 15 mm long) per flowering shoot and the leaves appear terete and robust, being narrow but very short. Plants from the Hex River Mountains have longer, more slender leaves and very small heads, borne in small groups of one to three.

Little Karoo: Plants from the Anysberg are similar to the Witteberg form but those from the Swartberg at higher altitudes generally have larger, broader leaves and larger heads, perhaps due to the moister, cooler growing conditions. Leaves can be very long and narrow (viz. Compton 3845 from the Little Karoo).

Kogelberg, Hermanus, Caledon, Jonaskop: in the Kogelberg region the leaves are very slender, often short, and the heads small to moderate in size, and borne in small to medium-sized synflorescences.

Langeberg: Specimens from the higher, wetter northern slopes of the Riviersonderend and Langeberg are generally more luxuriant with longer, sparser leaves than those from the Witteberg region, and have generally large heads that are never solitary, being borne in groups of 4 up to ±18. Many of these specimens have broader leaves with copious long hairs (e.g. from the Garcia’ s Pass area near Riversdale). Several specimens from the lower north slopes above Witbooisrivier in the Boosmansbos area, however, have extremely terete, short and straight leaves and small, often solitary heads (e.g. McDonald & Morley 1113 [NBG]). On the southern slopes of the Langeberg and on the Potberg, specimens have very luxuriant, large and broad leaves, and large, copiously clustered heads.

Albertinia, Mossel Bay, George : Plants from the inland Albertinia region are generally large with extremely long and relatively broad leaves, and large, numerous heads (e.g. Stirton 10,258 [NBG]), although nearer the coast they are more typical. Leaves in this area can be very lush.

Knysna, Plettenberg Bay : Specimens from the coast in this region represent a peculiar and distinctive form, having very densely imbricate, broad, lanceolate leaves and large, spherical heads. The peduncles are erect and held close together while the leaves below the peduncle are appressed to the stem, creating the effect of a single large pedunculate inflorescence (e.g. Taylor 2914, Noetzie hills [NBG]).

Port Elizabeth and Grahamstown: Very few collections have been made east of the 24̊ meridian. These plants are generally large with long, broad and sparse leaves, and large heads.

Conservation status: Although the current concept of Achyrantheum paniculatum is narrower than that of Syncarpha paniculata , it is likely to have the same assessment of Least Concern due to being widespread and relatively common.

History: Achyranthemum paniculatum was first described as ‘ Xeranthemum incanum , foliis oblongo-acutis, capitulis plurimis, argenteis’, by Johannes Burmann in his pre-Linnean ‘Rariorum Africanarum Plantarum’ (1739). Burmann mentions in his description the herbarium of Witsen, as well as Paul Hermann, the first known plant collector at the Cape in 1672. The illustration accompanying the description perfectly matches a specimen in G-PREL which was designated as the lectotype by Hilliard and Burtt (1981a). The G-PREL specimen is annotated as having come from the herbarium of Delessert. More slender, narrow-leaved and smaller-headed specimens were separately described by Schrank, 1824 as Anaxeton racemosum , based on a specimen sent to him by J. Brehm, a medicinal pharmacologist from Bavaria who set up a garden and pharmacy in Uitenhague. Subsequent authors assumed this species to be the same as the yellow-headed Achryanthemum mucronatum , despite the difference in bract colour, although Candolle (1838) recognised the yellow-headed and white-headed forms as different varieties of H. mucronatum ( var. mucronatum having ‘pallide citreis’ [pale yellow] bracts while those of var. niveum were ‘niveus’ [white]). Both these names, however, apply to specimens with narrow leaves and small capitula, features which were used instead of bract colour as the main criteria to distinguish this concept from other taxa.Later authors continued to consider these two taxa as conspecific, first as Helichrysum mucronatum (Berg.) Less and then Syncarpha mucronata (Berg.) B.Nord. , and currently the Syncarpha mucronata folders in many herbaria house both white- and yellow-headed specimens. We consider them to be distinct because the bract colour difference is never equivocal, all specimens clearly having either yellow or white bracts, and because the colour difference is associated with striking differences in both distribution and habitat.

Selected list of specimens seen (see Supplementary Materials for full list):

South Africa: Western Cape.–3118 (Vanrhynsdorp): summit of Kobe Pass, Urianskraal, (–DB), 14 Oct 1973, Hall 4509 (NBG, PRE); Gifberg, stony E. slopes, (–DC), 15 Oct 1953, Esterhuysen 22,119 (PRE). –3218 (Piketberg): near Clanwilliam, (–BB), Bolus 2065 (BOL); summit and west edge of summit of the Zandberg, (–DA), 27 Oct 1938, Pillans 8573 (BOL). –3219 (Clanwilliam): Pakhuis mountain, (–AA), Leipoldt 3624 (NBG, PRE); Wupperthal, (–AC), Emdon 217 (PRE); Citrusdal. Moreson, mountain slope south of homestead, (–CA), 9 Nov 2001, Hanekom 3367 (NBG, PRE); Groot Winterhoek MCA: Grootfontein, West of Olifants River., (–CC), 16 Nov 1985, Rheeder 154 (PRE); Knolfontein, Swartruggens, 60 km NE of Ceres , (–DC), 19 Oct 2005, Jardine & Jardine 259 (NBG). –3318 (Cape Town): Paarl, (–DB), Rogers 10,519 (PRE). – 3319 (Worcester): Tweedside, north of Tweedside farmhouse on Doppies se rand, (–AB), 14 Oct 1995, Meyer 1141 (PRE); Vleiberg, path from akkerbome towards Vleiberg, on far side of river as path switches back, arid fynbos, (–BA), 12 Dec 2010, Bergh 2224 (NBG); near Jonaskop T.V. aerial site, (–DC), 30 Nov 1976, Walters 1607 (NBG). –3320 (Laingsburg): Poort N of Pienaarskloof, (–AA), 12 Sep 1965, Acocks 23,697 (NBG, PRE); Witteberg Mountain, Matjesfontein, (–BA), 8 Aug 1933, Humbert 9803 (PRE); Anysbeg, North-facing slope, near highest point of mountain, Wolfhuiskloof, (–DA), 10 Aug 1993, Meyer 155 (BOL, PRE); Tradouw Pass, Swellendam end, (–DC), 27 Oct 1938, Walgate s.n. (BOL 46,784); Langeberge, Boosmansboswildernis Gebied, bokant Witbooisrivier, S kant van berg, (–DD), 16 Jan 1986, Burger 64 (NBG, PRE). –3321 (Ladismith): Klein Swartberg, Towerkop, rocky Mountain slope, (–AC), 1 Nov 2007, Pienaar T1 (NBG); SE side ofTouwsberg, Farm Rietfontein, top of dry ridge, foothills, (–CA), 7 Oct 1993, Chesselet & Hartzer 90 (PRE); Riversdale, Overwacht Farm/ Riversdale turn off R323, Garsia Pass, leading to Ladysmith, Langeberg turn off, Garsia Pass to Overwacht and Langeberg farm, (–CC), 16 Feb 2004, Botha (4)080 (NBG); Little Karroo, Roodeberg, (–DA), 5 Jul 1937, Levyns 6064 (BOL). –3322 (Oudtshoorn): summit ridge west of Forestry hut, top of Swartberg Pass, (–AC), 11 Nov 1983, Jackson 10 (BOL); Swartberg, Evkom Road, northern slope between grass and reeds, (–AD), 21 Oct 1976, Pienaar 42 (NBG, PRE); Swartberg, ridge E of Blesberg, (–BC), 6 Jan 1975, Thompson 2299 (NBG, PRE); Swartberg N of Kolberg, (–BD), 7 Jan 1975, Oliver 5677 (NBG); TR417: Outeniqua Mountains, Robertson [Robinson] Pass, (–CC), Hops 61 (BOL); top of Montagu Pass, (–CD), Fourcade 1609 (BOL); base of Swartberg Pass, south side, (–DA), 13 Mar 2011, Haiden 9 (NBG); in collibus Kamanassiebergen prope Avontuur, (–DB), Bolus 1672 (BOL); hills North of Ganz Kraal, Long Kloof, (–DC), Fourcade 3406 (BOL, NBG); Saasveld, (–DC), 25 Nov 1970, Von Breitenbach 115 (PRE); Knysna Division, Van der Waltshoek, (–DD), 22 Oct 1922, Keet 1003 (PRE).–3323 (Uniondale/Willowmore): Slypsteenberg, South slopes, (–AC), 3 Nov 1941, Esterhuysen 6330 (BOL, NBG, PRE); Ongelee, 4 miles N. of P.O., (–CB), 16 Nov 1958, Acocks 20,003 (PRE); Knysna Forest , (–CC), 27 Apr 1926, Kapp 87 (PRE); Knysna Division, Forest Hall, sea slopes above Crags, (–CD), Fourcade 4176 (BOL); Kougaberge: Plaas Hoeree, (–DB), 22 Sep 1986, Oelofsen 129 (PRE); Die Hoek, North foot of Zitzikama Mountains near Joubertina, (–DC), 10 Feb 1952, Esterhuysen 19,941 (BOL); Peak Formosa, Zitzikamma Mountains, amongst rock on rocky ridge, north slopes of peak, (–DC), Dec 1957, Esterhuysen 27,393 (BOL). –3418 (Strand): Elgin Basin, Arieskraal Farm (portion Arieskraal), entering form Somersfontein, powerline road crossing small stream, (–BB), 27 Jan 1996, Rode 605 (NBG); Hangklip, (–BD), 23 Nov 1958, Taylor 5893 (NBG); 23 Nov1958, Taylor 5897 (NBG). –3419 (Caledon): Houwhoek, (–AA), 20 Oct 1951, Maguire 1107 (NBG); Swartberg, (–AB), unknown (BOL); Hermanus, (–AC), 9 Nov 1921, Rogers 26,472 (PRE); Vogelgat, near Banksi Ridge, (–AD), 9 Dec 1979, Williams 2950 (NBG); Boesman's Kloof Pass at McGregor, (–BA), 11 Oct 1940, Esterhuysen 4844 (BOL); Keeromskloof, Salmonsdam Nature Reserve, Stanford, (–BC), 11 Sep 1981, Van Wyk 595 (NBG, PRE); Hartebeest Rivier, (–BC), Elbrecht 22,128 (PRE); Hagelkraal River, (–DA), 27 Dec 1946, Leighton 2549 (BOL). –3420 (Swellendam): Riviersonerend Mts., Swellendam, at Stormsvlei Hassaqhaskloof + at the Breede Rivier, (–AA), Zeyher 2855 (PRE); De Hoek farm, above Buffeljagsdam, toward Meulkloof 4x4 track, Swellendam, S side of Langeberg, (–BA), 12 Apr 2011, Haiden 33 (NBG); Haiden 34 (NBG); De Hoop, Potberg, SE facing slopes, c. 1000 m from Elandspad Homestead, N of road, (–BC), 19 Sep 1984, Morley 133 (NBG, PRE [mixed collection with A. racemosum ]); upper South-West slope of the Potberg, (–BC), 12 Oct 1940, Pillans 9300 (BOL, PRE); De Hoop - Witwater, (–BD), 6 August 1984, Van Wyk 1708 (NBG, PRE). –3421 (Riversdale): Gysmanshoek Pass, 2 km south of The Oaks, (–AA), 16 Sep 1981, Hugo 2758 (PRE); Nature Reserve near Riversdale, (–AB), 11 Oct 1932, Hubbard 244 (NBG); roadside near Albertinia , (–BA), 27 Jul, Leighton 3305 (BOL, PRE); near Albertinia , (–BA), 2 Oct 1928, Gillett 1168 (NBG); Ystervarkpunt (Gouriqua) Releve 229, (–BC), 26 Jun 1987, Willemse 360 (NBG); ± 10 km NW of Gouritz River Mouth, (–BD), 25 Sep 1980, Snijman 320 (NBG). –3422 (Mossel Bay): Great Brak River Mouth, (–AA), 12 Nov 1981, Parsons 425 (NBG); Witte Els River (Malgaten No 2), East side, 9.7 m. from George, (–AB), 27 Nov 1943, Fourcade 6288 (BOL); Gwaing River, SE slope, top of clif at W bank of river, (–AB), 26 May 1984, Van Wyk, Fellingham & O'Callaghan 220 (PRE). –3423 ( Knysna ): Knysna Heads , (–AA), 23 Dec 1949, Martin 27 (NBG); Roberg, 2 m. East of Plettenberg Bay, (–AB), Jan 1934, Compton 4455 (BOL, NBG). Eastern Cape. –3323 (Willowmore): Uniondale Division, hills from Misgund to Spitzkop, (–AD), Fourcade 4244 (BOL); Tsitsikama Park, Uitkyk facing sea hillside, (–DD), Bokelmann PL63No.2 (PRE).).–3324 (Steytlerville): near Hankey on Loerie road, on Enon sandstone, (–DD), 1 Nov 1979, Cowling 1206 (GRA). –3325 (Uitenhague): Blueberg: Loerie, (–CC), 15 Sep 1934, Dix 15 (GRA); Greatwinterhoek Mts., Uitenhage Division, Vyeboomskloof catchemnet basin Groendal Wilderness Res., (–CA), 24 Mar 1975, Scharf 1797 (PRE); Port Elizabeth area; flower show collection, (–DC), Archibald & Britten s.n. (GRA, PRE). –3326 (Grahamstown): Albany District, Coombes Valley, (–BD), 26 Oct 1968, Bayliss 4366 (NBG).

Figures

Fig.3. Achyranthemum paniculatum. A.Leafindumentum (Gillett 1987, NBG).B.Leaves.C.Habit.D.Capitula.E.Synflorescence.F.Distribution;black circles are localities georeferenced with a confidence of 10,000 m or less; white circles could not be placed to an accuracy of within 10,000 m. All photographs N.G. Bergh.