Pteronia decurrens Bello, Magee & Boatwr., 2020

2. Pteronia decurrens Bello, Magee & Boatwr. View in CoL , sp. nov.

Type:— SOUTH AFRICA, Western Cape Province, Montagu (3320): Wittepoort, Laingsburg (–BB), 23 September 1941, Compton 11851 ( holotype NBG!) .

Evergreen perennial shrublet ca. 0.3 m in height, much branched; branches erect, glabrous. Leaves decussate, contiguous at base, viscid, simple, linear, 4–10 × 1–2 mm, flattened, coriaceous, tuberculate; apex obtuse; margins entire. Capitula 10- to 12-flowered, homogamous, discoid, apically constricted, decurrent, terminal, solitary, sometimes in clusters of 2 or 3, sessile. Involucre globose, shortly campanulate when opened, 7–10 × 4–7 mm, ca. 8-seriate; involucral bracts glabrous; stereome prominent, slightly fleshy; margins finely ciliate, hyaline; outermost bracts lanceolate, 3–4 mm long; apex acute; middle bracts ovate, 5–6 mm long; apex subacute; innermost bracts oblong-ovate, 7–8 mm long; apex subacute to obtuse. Florets bisexual; corolla yellow, tubular, 7–9 mm long; limb 5-lobed, gradually widening upward; tube pubescent on the middle; anthers 3–4 mm long; apical appendages acute; filament not swollen distally; style branched, 7–8 mm long; branches flattened, ca. 3 mm long, stigmatic-papillate. Pappus of barbellate bristles, biseriate, connate at base, 4–5 mm long, shorter than florets at fruiting stage, straight, straw-coloured. Cypselae ovate, 2–3 × 1–2 mm, dorsiventrally flattened, contracted into a neck at apex, glandular and villous ( Figure 3 View FIGURE 3 ).

Diagnostic characters:— Pteronia decurrens shares the glabrous branches, linear leaves, apically constricted capitula, globose involucre and ovate, glandular-villous cypselae with Pteronia pallens Linnaeus (1782: 357) . However, Pteronia decurrens can readily be distinguished by the smooth, unridged branches (fissured and ridged in P. pallens ), shorter ( 4–10 mm long) tuberculate leaves ( 10–20 mm long and glabrous in P. pallens ), decurrent capitula (excurrent in P. pallens ) and unfringed bracts with a prominent stereome (prominently fringed and without a prominent stereome in P. pallens ).

R.H. Compton collected both Pteronia decurrens and P. pallens at Wittepoort, Laingsburg ( Compton 11851 & 11852, NBG) and considered the two collections to represent different species (identifying Compton 11852 as P. pallens but unable to identify Compton 11851).

Distribution and Ecology:— Pteronia decurrens occurs between Laingsburg and Uniondale in the Little Karoo ( Figure 2 View FIGURE 2 ). It favours stony or rocky soil from 250–701 m (a.s.l.). Flowering is from spring to early summer (September– December).

Additional specimens examined:— SOUTH AFRICA. Western Cape: 3320 ( Montagu): 14 miles [ 22.54 km ] southeast of Laingsburg (–BB), Acocks 20760 ( PRE) . 3321 ( Ladismith): Goedehoop, 10 km south of Calitzdorp (–DA), 29 September 2006, Bruyns 10536 ( BOL) . 3323 ( Willowmore): Near Uniondale Road Station (–CA), Maguire 784 ( NBG) .