Pteronia armatifolia Bello, Magee & Boatwr., 2020

1. Pteronia armatifolia Bello, Magee & Boatwr. View in CoL , sp. nov.

Type:— SOUTH AFRICA, Western Cape Province, Ladismith (3321): ± 18 km on Buffelsdrif (R62) road at Ladismith–Barrydale–Baviaanskraans road junction (–CA), 1 October 2006, Burgoyne 10731 (holotype PRE!) .

Evergreen perennial shrub ca. 0.3 m in height, much branched; branches erect, glabrous with short internodes (± 3 mm). Leaves decussate, free at the base, simple, narrowly ovate, 6–10 × 3–5 mm, flattened, coriaceous, glabrous, midrib occasionally sparsely setose on abaxial surface; apex acute or subacute with prominent setose cluster; margins setulose. Capitula 15- to 20-flowered, homogamous, discoid, terminal, solitary, shortly pedunculate (± 3 mm). Involucre narrowly campanulate, 15–25 × 6–12 mm, 4- or 5-seriate; involucral bracts glabrous with stereome on upper part; apex obtuse; margins narrowly membranous; outermost bracts orbicular, 3–4 mm long; middle bracts oblong, 8–10 mm long; innermost bracts oblong, 12–13 mm long. Florets bisexual; corolla yellow, tubular, 9–10 mm long; limb 5-lobed, widening upward; tube glabrous, 4-ribbed; anthers 3–4 mm long; apical appendages acute; filament not swollen distally; style branched, 10–11 mm long; branches flattened, ca. 3 mm long, stigmatic-papillate at tips. Pappus of barbellate bristles, biseriate, connate at base, 11–12 mm long, slightly longer than florets at fruiting stage, straight, straw-coloured. Cypselae ovate, 6–7 × ± 4 mm, dorsiventrally flattened, usually contracted into a neck at apex, sparsely glandular on lower part with short tufted hairs at base ( Figure 1 View FIGURE 1 ).

Diagnostic characters:— This species shares the glabrous branches, flattened leaves and basally hairy cypselae with Pteronia adenocarpa Harvey (1865: 109) and P. viscosa Thunberg (1800: 144) but can be readily distinguished by the narrowly ovate leaves with a prominent apical cluster of bristles (leaves oblanceolate to broadly ovate without an apical cluster of bristles in P. adenocarpa and P. viscosa ) and ribbed corolla tube (corolla tubes not ribbed in P. adenocarpa and P. viscosa ). Pteronia armatifolia has been previously confused with P. adenocarpa from which it can be further distinguished by the glabrous leaf lamina with the margins not revolute (lamina punctate with revolute margins in P. adenocarpa ) and very sparsely glandular cypselae with straight pappus bristles (cypselae densely glandular, pappus bristles with a tortuous band near the base in P. adenocarpa , Figure 1I View FIGURE 1 ).

Distribution and Ecology:— This species is known only from a single collection around the Rooiberg near Ladismith in the Little Karoo, Western Cape ( Figure 2 View FIGURE 2 ). It favours rocky soil at ca. 326 m above sea level (a.s.l.). Flowering occurs in spring (October).