Pteronia glandulosa Bello, Magee & Boatwr., 2020

Bello, Anifat O., Boatwright, James S., Bank, Michelle Van Der & Magee, Anthony R., 2020, Four new species of Pteronia (Astereae, Asteraceae) from South Africa, Phytotaxa 430 (1), pp. 25-32 : 30-31

4. Pteronia glandulosa Bello, Magee & Boatwr. , sp. nov.

Type:— SOUTH AFRICA, Northern Cape Province, Springbok (2917): Northwest of Steinkopf, southeast of Kosies (–BA), 25 August 2012, Koekemoer 4350 (holotype PRE!) .

Evergreen perennial shrub ca. 1.6 m in height, less branched; branches erect, grey-scaly, young branches setulose, older glabrous. Leaves decussate, free at the base, clustered, simple, narrowly to broadly obovate, leaves becoming broader towards inflorescence, 5–12 × 2–5 mm, flattened, young leaves somewhat succulent, older subcoriaceous, glandular with ruptured glands creating a viscous appearance in older leaves; apex subacute to obtuse, usually mucronate; margins glandular or entire; axillary fascicles often present. Capitula many-flowered (>25), homogamous, discoid, terminal, solitary, subsessile. Involucre obconical, 10–21 × 8–15 mm, 4- to 6-seriate; involucral bracts glabrous, oblong; stereome slightly prominent; apex acute; margins hyaline-ciliate or jagged; outermost bracts 4–5 mm long; middle bracts 7–8 mm long; innermost bracts 10–12 mm long. Florets bisexual; corolla pale yellow, tubular, 10–12 mm long; limb 5-lobed, widening upward; tube glabrous; anthers 4–5 mm long; apical appendages subacute; filament not swollen distally; style branched, 10–12 mm long; branches flattened, ca. 4 mm long, densely stigmatic-papillate at tips. Pappus of barbellate bristles, biseriate, connate at base, 7–8 mm long, shorter than florets at fruiting stage, straight, creamish. Cypselae oblong, 3–4 × ± 1 mm, dorsiventrally flattened, slightly contracted into a neck at apex, densely sericeous ( Figure 6 ).

Diagnostic characters:— Pteronia glandulosa shares the obconical, ca.6-seriate capitula with Pteronia leucoclada Turczaninow (1851: 65) but can readily be distinguished by the decussate, obovate, glandular leaves (alternate or spiral, linear or club-shaped and glabrous in P. leucoclada ), non-spinous involucral bract apices (spinous in P. leucoclada ), biseriate pappus (multiseriate in P. leucoclada ) and sericeous cypselae (villous in P. leucoclada ).

Distribution and Ecology:— This species occurs on granite hills near Steinkopf in the Northern Cape Province ( Figure 5 ). It favours stony or rocky soil at 578 m (a.s.l.). Flowering in spring (August).

Figures

FIGURE 5. Known distribution of Pteronia flava (circles) and P. glandulosa (triangle).

FIGURE 6. Morphology of Pteronia glandulosa. A. Flowering branches; B. Glandular leaves; C. Viscid old leaf; D. Floret; E. Capitulum; F. Cypsela. Voucher: Koekemoer 4350, PRE. Scales: B–D = 2 mm, E = 5 mm, F = 1 mm.