Pteronia cederbergensis Bello, Magee & Boatwr., 2017

Bello, A. O., Boatwright, J. S., Tilney, P. M., Van der Bank, M. & Magee, A. R., 2017, A taxonomic revision of the Pteronia camphorata group (Astereae, Asteraceae) *, South African Journal of Botany 113, pp. 277-287 : 284-285

3. Pteronia cederbergensis Bello, Magee & Boatwr. sp. nov.

Type: South Africa. Western Cape, Wuppertal (3219): Knolfontein, Swartruggens 60 km north-east of Ceres (–DC), Jardine 1762 (NBG, holo.!).

Pteronia camphorata L. var. laevigata Harv. in Harv. & Sond. Fl. Cap. 3: 110 (1865); Hutch. & Phillips in Ann. S. African Mus.9: 298 (1917), syn. nov. Type: South Africa. Piquetberg , near 24- Rivers, Zeyher 810 (TCD!, lecto., here designated; SAM!, isolecto.). [Note: Harvey cites only the Zeyher 810 collection in the protologue. The specimen from Harvey's own collection at TCD is selected here].

Evergreen perennial shrubs, 0.3–1.0 m high; much branched, branches glabrous. Leaves opposite, becoming sub-opposite towards the inflorescence, diffuse, spreading, simple, linear, 6.0–13.0 × ±1.0 mm, subterete, somewhat succulent, glabrous; mucronate, margins entire, fascicula te. Capitula homogamous, discoid, 10- to 20-flowered, terminal, solitary or sometimes in clusters of 2 to 8. Involucre campanulate to obconical, 10–15 × 15–20 mm, 3-seriate; involucral bracts glabrous, stereome prominent; margins shortly serrate, narrowly scarious; outermost bracts ovate to lanceolate, 2–3 mm long, apex acute; middle bracts lanceolate, 5–6 mm long, apex acute; innermost bracts lanceolate, 8–10 mm long, apex acute to acuminate. Florets bisexual, 10 to 20; corolla bright yellow, tubular, 9–11 mm long, limb 5-lobed, gradually widening upward, tube glabrous; anthers 3–4 mm long, apex acute, base terete; style branched, 13–14 mm long, branches flattened, about 3.6 mm long, densely stigmatic-papillate. Pappus 2-seriate, bristles, connate at base, 6–10 mm long, slightly shorter than florets at fruiting stage, straw-coloured. Cypselas obclavate, 6–7 mm × 1.5–2.0 mm, dorsoventrally flattened, marginal ribs not prominent, usually contracted into a neck at apex, glabrous, brown, shiny. Fig. 9 .

Diagnostic characters

Pteronia cederbergensis is readily distinguished by the glabrous branches, diffuse, opposite, somewhat succulent leaves ( Fig. 9A ) that lack glands, glabrous corolla tube, 2-seriate pappus and the longer, obclavate cypselas (6–7 mm long) ( Fig. 9D ).

Distribution and ecology

This species is restricted to the Cederberg and Koue Bokkeveld Mountains in the Western Cape ( Fig. 10 ). It favours rocky soils from 100 to 1590 m. Flowering is in spring and mid-summer (September to January).

Specimens examined

South Africa. WESTERN CAPE: 3218 (Clanwilliam): Cederberg: Sederhoutkop, upper slopes (– BB), Taylor 10778 ( NBG, PRE). 3219 (Wuppertal): North Cederberg: Summit of Krakadouw Peak (– AA), Taylor 10887 ( NBG); Boontjieskloof, North Cederberg (– AA), Taylor 7479 ( PRE); Middelberg Plateau, Cederberg (– AC), Bond 1334 ( NBG), Kerfoot 6175 ( NBG), Esterhuysen 2474 ( PRE); Cederberg Wilderness area, Groot Koupoort (– AC), Haynes 1301 ( NBG, PRE); Algeria State Forest, near Hoogvertoon (– AC), Viviers 22 ( PRE); Clanwilliam Division, Cederberg into Middelberg (– AC), Esterhuysen 1264 ( PRE); Cold Bokkeveld, East end of Elandskloof, ca 33 km south of Citrusdal (– CA), Goldblatt 5242 ( PRE); Knolfontein, Swartruggens 60 km north-east of Ceres (–DC), Jardine & Jardine 299, 1007, 1029 ( NBG). 3319 (Wocester): West road between Rosendalfontein & Visgat (– AA), Pillans 9682 ( NBG, PRE); Gydouw Pass (–AB), Compton 10062 ( NBG); Cold Bokkeveld, Rocklands Peak in Skurweberg, West slopes (–AB), Oliver 9069 ( NBG); On the Groot River road from Cold Bokkeveld to Cederberg (–AB), Taylor 6124 ( PRE, NBG); Mountain above Ceres Peak (– AD), Barker 9109 ( NBG); Prince Alfred Hamlet, south-west top of Gydouw Pass (– AD), Bayer 6328 ( PRE); Ceres Division, Visgat, upper Olifants River valley, rocky river bank (– AD), Esterhuysen 13402 ( BOL); Baviaansberg, Ceres Division (– BA), Stokoe s.n. ( BOL); Lakenvlei (– BC), Compton 12072 ( NBG); Ceres Division, Conical Peak (– BC), Stokoe 59951 ( PRE); Worcester Division, between Darling bridges, Roman's River (– CB), Isaac s.n. ( BOL); Elandskloof, Ceres Division (–CD), Levyns 5101 ( BOL).

Figures

Fig.9. Morphology of Pteronia cederbergensis. A – flowering branch.B – style.C – involucral bracts.D – cypselas (D1 – immature,D2– mature).E – floret,F– corolla.Vouchers:A–E– Pillans 9682 (NBG), F – Levyn 5101 (BOL).Scales: A = 4 cm, B–E = 2 mm, F = 1 mm.

Fig. 10. Known distribution of Pteronia cederbergensis.