Othonna spinescens DC.

Magoswana, S. L., Boatwright, J. S., Magee, A. R. & Manning, J. C., 2022, A taxonomic revision of the Othonna coronopifolia L. group (Asteraceae: Senecioneae: Othonninae), South African Journal of Botany 149, pp. 604-616 : 606

2. Othonna spinescens DC. , Prodr. 6: 476 (1838); Harv. in Fl. Cap. 3: 332 (1865).

Type: South Africa, [Western Cape], ‘in Africa^Capensi’ [‘Zwischen Droogeheuvel und Jakhalsfontein’] [between Drooge Heuvel and Jakalsfontein ], Sep (without year), Drege [619 pp.] (G-DCG00473628, holo.—image!; P-0010007—image!, iso.) .

Shrubs to 1.5 m, stems woody, simple or branched in upper half, branches erect to flexuous, mostly spine-tipped, striate, pale grey, leaf axils cobwebbed. Leaves alternate, mostly fasciculate on short-shoots, subsessile, blade narrowly oblanceolate, subterete in section, sessile, 10 - 40 £ 2 - 4 mm, entire, leathery to succulent. In fl orescence either terminal on stems and then a divaricately branched corymb the peduncles becoming woody and spinescent after flowering, or solitary sub-erect capitula terminal on short-shoots; peduncles 40 - 60(- 80) mm long. Capitula radiate, rays and discs yellow. Involucre 10 - 15 mm diam., bracts 7 or 8, lanceolate, 8 - 12 £ 2 - 4 mm, connate in basal 1/3 to 1/2. Ray florets 7 or 8, corolla tube 3 - 5 mm long, limb elliptic, 7 - 10 £ 2 - 5 mm; ovary ellipsoid to obovoid, appressed-puberulous with white twin-hairs; style branched in upper half of tube. Cypselae ellipsoid-ovoid, 3 - 6 £ 2 - 4 mm, densely appressed-puberulous on ribs with myxogenic, white, twin-hairs; pappus 8 - 15 mm long, beige. Disc fl orets numerous, corolla tube 2 - 4 mm long, lobes lanceolate to ovate, 0.5 - 1.0 long; filaments 1 - 2 mm long; ovary 3 - 5 mm long; style simple and cone-tipped; pappus of § 10 barbellate bristles, united basally.

Distribution and Ecology: Othonna spinescens is narrowly distributed along the drier interior of the southwestern mountains of the Western Cape, from the eastern Cederberg through the Swartruggens south to Karoopoort (Fig. 4); on rocky sandstone slopes at elevations above 1 000 m. Flowering from June to September.

Diagnosis: Othonna spinescens is distinguished by its narrowly oblanceolate leaves, 10 - 40 mm long and subterete in section, and an inflorescence that is either terminal on the stems and then a divaricately branched corymb with the peduncles becoming woody and spinescent after flowering, or solitary sub-erect capitula terminal on short-shoots ( Figs. 1E & 2E 1-E 3 ). The other thorny or spinescent species in the group, O. pteronioides , has distinctive divaricate branching, smaller leaves, 3 - 10 mm long, that are oblanceolate or elliptic in outline and elliptic in section, and mostly solitary capitula.

3.4. Additional specimens examined

South Africa. WESTERN CAPE: 3219 (Wuppertal): Farm Zuurfontein, behind Tafelberg (- AC), 27 Aug 1975, Owen s.n. ( NBG); 15 Sep 2002, Bryuns 9309 ( BOL) Matjiesrivier Nature Reserve, S of Geelkloof (- AD), 1 Aug 1999, Low 4617 ( NBG); 10 Aug 1996, Lechmere-Oertel 626 ( NBG); Swartruggens, (- DC) 23 Sep 1926, Levyns 1777 ( BOL); Swartruggens, between Katbakkies and Skitterykloof (- DC), 12 Aug 2012, Koekemoer 4313 ( PRE); 60 km NE of Ceres (- DC), 14 Jul 2005, Jardine and Jardine 13 ( NBG); 31 Jul 2018, Jardine 2821 ( NBG); Katbakkies Pass to R305 road (- DC), 14 Oct 2008, Cowell, Bennett and Pekeur MSBP 3780 ( NBG); Waterval, W of Elandsvlei (- DC), 12 Sep 2006, Bruyns 10523 ( NBG); top of Skitterykloof (- DC), 13 Sep 2008, Bruyns 11221 ( NBG). 3319 (Worcester): Karoopoort (- BA), 30 Sep 1933, Levyns 4644 ( BOL); 30 Jun 1940, Compton 8904 ( NBG); 27 Jul 1941, Bond 1190 ( NBG); 27 Jul 1941, Esterhuysen 5482 ( BOL).

Figures

Fig. 1. General morphology of the O. coronopifolia group. A.Habit of O. coronopifolia showing obovate to oblanceolate leaves and capitula with 7 or 8 ray florets; B. Habit of O.leptodactyla showing the linear or narrowly lanceolate leaves and capitula with 7 or 8 ray florets; C1-C2. Habit of O. pteronioides showing the small oblanceolate to elliptic leaves in axillary tufts, the divaricate branches ending in thorns and capitula on short-shoots; D. Habit of O. ramulosa showing the leaves fasciculate on short-shoots and capitula with 7 or 8 ray florets; E. Habit of O. spinescens showing the woody spinescent peduncles, the fasciculate leaves on short-shoots and an involucre with 7 or 8 ray florets; F1-F2 Habit of O. pavonia showing the pinnatisect leaves, the deep red or maroon stems, solitary inflorescence and capitula with 5 ray florets. Photographs: A-E by J. Manning; F1-F2 by L. Magoswana.

Fig. 2. Vegetative variability in species of the O. coronopifolia group (A1-A3, O. coronopifolia) (A1) showing dwarf plants growing along the coast, obovate-oblong, cuspidatemucronate leaves; (A2) plants with capitula on short-shoots, the peduncle mostly 50̅150 mm long; (A3) larger plants mostly with leaves often irregularly toothed or sometimes 3- pinnatifid, often in axillary tufts and on short-shoots; (B1-B2, O. leptodactyla) showing the linear or narrowly lanceolate leaves with linear lobes; (C1-C2, O.ramulosa) (C1) showing leaves mostly fasciculate on short-shoots, oblanceolate, inflorescence terminal on stem, old peduncles ending in thorns; (C2) leaves elliptic, narrow below and petiole-like, inflorescence on short-shoots along stem; (D1-D2, O. pteronioides) showing the divaricately branched habit, tips developing into thorns, the small oblanceolate-elliptic leaves, inflorescence terminal on stems or on short-shoots; (E1-E3, O. spinecens) showing an inflorescence that is either terminal on stems and then a divaricately branched corymb the peduncles becoming woody and spinescent after flowering, or solitary sub-erect capitula terminal on short-shoots and narrowly oblanceolate leaves; (F, O. pavonia) showing the pinnatisect leaves, an inflorescence of few to several capitula in lax corymbs and deep red to maroon stems when young and 5 ray florets and involucral bracts.

Fig. 3. Distribution of Othonna pavonia.