Corbichonia exellii Sukhor., 2015

Sukhorukov, Alexander P. & Kushunina, Maria, 2015, Taxonomy and chorology of Corbichonia (Lophiocarpaceae s. l.) with further description of a new species from Southern Africa, Phytotaxa 218 (3), pp. 227-240 : 230

3. Corbichonia exellii Sukhor. sp. nov.

Type:— ANGOLA. Mossamedes [Namibe province]: 74 km from Mossamedes, Montemor, dry scrub, ca. 500 m, 19 May 1937, Exell & Mendonça 2186 (holotype, BM-001122713!) ( Fig. 3 ).

Description: —Plants up to 50 cm, very branched from the base; insignificantly lignified white perennial stems bearing angular, upright or ascending annual shoots ( Fig. 4A ) that are glabrous or sometimes can be covered with solitary simple and short-stalked glandular hairs; all leaves fleshy, glaucous, cuneate, apex shortly mucronate; lowermost leaves obovate, 3.0–7.0 × 1.5–3.0 cm, middle and upper leaves oblong or ovoid ( Fig. 4B ), with shortened vegetative shoots in their axils; inflorescences monochasial looking umbel-like ( Fig. 4C ); sepals approximately 4 mm, slightly accrescent (to 6 mm) in fruit; 20–30 petal-like staminodia ( Fig. 4D ), mauve or pink; stamens 20 or more, anthers white; capsule orbicular, 6–7 mm in diameter, papery; seeds numerous, 1.0– 1.2 mm, reniform; testa cells without papilla-like elongations ( Fig. 5 G, H, I ).

Habitat: —Scrubs, limestone, deserts and ruderal sites; 0–700 m a.s.l. (upper extent of the altitude is not precisely known).

Phenology: —Flowering December–June; fruiting February–July.

Conservation status:—The appropriate data on abundance and/or distribution of the taxon is lacking. It can be included in the Not Evaluated (NE) category of IUCN Red List categories ( IUCN 2014) as there is inadequate information to make a direct or indirect assessment of its risk of extinction based on its distribution and/or population status.

Specimens examined:— ANGOLA. Namibe: Mossamedes inter 14 & 16 lat., 1859 & June 1860, Welwitsch 2418 (BM, K) ; 108 km from Mossamedes railway, 28–30 April 1909, Pearson 2800, 2863 (K) ; Mossamedes, Capangombe , June 1950, Teixeira 316 (BM) ; Mossamedes , 10 January 1956, Santos 134 (BM) ; Mossamedes, Caracul, 5 May 1962, Azancot de Menezes 248 (K, P—photo!) ; Zaire: Lengue , 19 December 1932, Gossweiler 689 (BM, K) . NAMIBIA. [Omaheke Region / Otjozondjupa Region] Hereroland, 1898, Dinter 66 (UZH-000075600—photo!) ; [Karas region] Great Karasberg [Karasburg], on loose step shale slopes in Waterfall ‘ Alt Ravine’ , common locally, bush with prostrate or ascending branches, fl. crimson, 21 January 1913, Pearson 8582 (BM) ; [Erongo region] Brandberg , 2000 ft, 9 April 1950, Macdonald 582 (BM) . SOUTH AFRICA. KwaZulu-Natal: Natal , 3000–4000 ft, April 1914, Wood 5391 (BM) ; Traansvaal , March 1894, Schlechter 4622 (BM) ; Northern Cape: Augrabies National Park , 28 o 29’6’’S, 20 o 4’29’’E, 559 m, 24 August 2005, Mothogoane 649 (P-05290981—photo!). Locus ignotus: SW Africa, Blesokranz, March 1950, McDonald 452 (BM) .

Etymology: —The species is named after A.W. Exell (1901–1993), an expert in South African flora.

Comments: —The new species was previously identified as C. decumbens , e.g. the above mentioned Angolan specimens (by Conçalves 1970). From both C. decumbens and C. rubriviolacea , the new species differs by narrower (oblong or ovoid) leaves and more compact (umbel-like) inflorescence. From morphologically similar C. decumbens , the new species is also distinguished by the seeds with the absence of cylindrical elongations of the testa cells, and both C. exellii and C. rubriviolacea share the similar seed ultrasculpture ( Fig. 5 ; see also the Table 1). The distribution area of C. exellii is restricted to Southern Africa ( Fig. 6 ), with the majority of locations from Angola and Namibia.

Figures

FIGURE 3. Holotype of Corbichonia exellii (BM-001122713!).

FIGURE 4. Images of Corbichonia exellii (NAMIBIA. Hardap region: Maltahöhe district, Kyffhäuser Farm, 24°28’46”S, 16°20’07”E, photographer A. Dreyer). A) General view of the plant in early blooming stage, B) fragment of the annual shoot showing the leaves from abaxial side, С) inflorescence supported by upper leaves, D) flower with petals (of staminodial origin).

FIGURE 5. Seeds of Corbichonia decumbens (A, B, C), C. rubriviolacea (D, E, F) and C. exellii (G, H, I). A, D, G: plan view of the seed; B, E, H: view from aril-side; C, F, I: ultrasculpture of seed surface (500x). Origin of the material: C. decumbens: Rwanda, Kirehe district: Bitshumbi, 1933, de Witte 1097 (K); C. rubriviolacea: Namibia, Karas region, March 2000, Mannheimer & Curtis CM830 (K); C. exellii: Angola, Mossamedes, May 1937, Exell & Mendonca 2186 (BM).

FIGURE 6. Distribution patterns of Corbichonia exellii (asterisks), C. decumbens (dots) and C. rubriviolacea (squares).