Austronea grandiflora Mart.

Martínez-Azorín, Mario, Crespo, Manuel B., Alonso-Vargas, María Ángeles, Dold, Anthony P., Pinter, Michael & Wetschnig, Wolfgang, 2018, Austronea (Asparagaceae, Scilloideae), a new genus from southern Africa, including the description of seven new species, Phytotaxa 365 (2), pp. 101-129 : 112-114

2. Austronea grandiflora Mart. -Azorín, M.B.Crespo, M.Pinter & Wetschnig sp. nov. ( Fig. 7 )

Ab Austronea vermiformi accedens folio unico angustoque, sed hac multo distincta folio parum carnosulo et magis complanato; floribus superne albicantibus vel laeviter roseocoloratis, majoribus, tepalis 7.6–8.6 mm long. (nec 4–5 mm long.) ad margines per anthesin longitudinaliter recurvatis, stylo longiore 3–4 mm long. (nec 1.5–2 mm long.).

Type:— SOUTH AFRICA. Northern Cape. Sutherland (3220): NW of Sutherland, 2 km from Sutherland-Calvinia R354 road, on turn off to Bo-Visrivier (- AB), elev. 1264 m, 15 April 2014 in flower ex hort at University of Alicante (Spain), M. Martínez-Azorín, A. Martínez-Soler & R. McKenzie MMA828b (holotype, GRA!; isotype, ABH!) .

Herbaceous deciduous geophyte. Bulb hypogeal, solitary, subglobose and usually depressed, 13–21 × 18–27 mm, extended into a hypogeal neck 2–3 cm long, with pale brown membranous outer tunics and white fleshy tightly packed inner tunics. Roots fleshy, white, branched, 5–30 × 0.6–1 mm. Leaf solitary, withered or almost withered at flowering time, aerial portion 25–52 × 4–6 mm, lorate-lanceolate, flattened, slightly contracted at ground level, dull dark green, usually showing a dark purplish ring at base, leathery, smooth, margins smooth or with minute papillae, prostrate to suberect, slightly curved, with a white hypogeal leaf portion connecting to the bulb neck. Inflorescence nodding in bud, raceme 2–5 mm long, capitate or subglobose, with 4–11 flowers; peduncle (2–) 6–8 cm long, erect or flexuose, glabrous, smooth; pedicels 10–15(–22) mm long at anthesis, suberect to spreading; bracts ovate-lanceolate, 1.5–2 mm long, clasping the pedicels, spurred, the lowermost with a spur of 1–2 mm long, membranous, white with a central darker band. Flowers pentacyclic, trimerous, stellate, opening in the afternoon and withering in the evening, up to 5 flowers open at a time, flower buds red. Tepals 6, entire, pinkish white on the adaxial side with a reddish darker longitudinal central band on the abaxial side, glandulous at the apex, biseriate, outer overlapping inner at the base, connate for ca. 1.5 mm to form a cup, free portions spreading; outer tepals lanceolate-oblong, 7.8–8.5 × 1.8–2.1 mm, with margins distinctly longitudinally revolute at anthesis which touch together to form a narrow atenuate distal half; inner tepals lanceolate, 7.6–8.4 × 1.9–2 mm, with margins somewhat revolute at anthesis although not touching together. Stamens 6, suberect, adnate to perigone for ca. 1.5 mm; filaments white, fleshy, subterete and attenuate to the apex, 6–7 × 0.8 mm, smooth; anthers yellow, oblong, ca. 1 mm long before dehiscence, dehiscing by longitudinal slits, with yellow pollen. Ovary reddish, obovoid, somewhat truncate to the style, 2–2.5 × 2 mm; style white, columnar, 3–4 mm long, slightly contracted at the base, trigonous in transversal section; stigma small and slightly papillate. Capsule and seeds unknown.

Etymology:—Named after its large flowers when compared to most other species in Austronea , only approaching the size of A. fimbrimarginata .

Phenology:— Austronea grandiflora flowers in November-December in the wild. In cultivation at the University of Alicante ( Spain) it flowered from March to May.

Habitat:—Grows on stony ground on inland plateaus between 1000 and 1500 m elevation with scarce vegetation in the Nama Karoo or Succulent Karoo biomes ( Mucina & Rutherford 2006).

Distribution:— Austronea grandiflora is known from some inland localities in the surroundings of Calvinia and the Roggeveld escarpment in the south western parts of the Northern Cape Province of South Africa ( Fig. 6 ).

Diagnostic characters and taxonomic relationships:— Austronea grandiflora is easily identified by the single, flat, lorate-lanceolate leaf, with smooth, not thickened, margin only minutely papillate when dry; the subcorymbose inflorescence with large flowers; tepals 7.6–8.5 mm long, pinkish white on the adaxial side with a reddish band on the abaxial side, with margins distinctly revolute longitudinally at anthesis and style 3–4 mm long. Most species of Austronea show smaller tepals, only 3–5 mm long, except in A. fimbrimarginata up to 7 mm long, but the latter species showing very different leaves and flowers ( Snijman & Harrower 2009). The single, elongated leaf of Austronea grandiflora is similar to that of A. vermiformis . However, the study of plants of the latter species from the type locality (Martínez-Azorín et al. MMA796, ABH59723!) show more succulent and less flattened leaves, and much smaller flowers, as said before. The original concept of A. vermiformis sensu Manning & Goldblatt (2007) was very broad and included several populations with narrow elongated leaves and variable width, occurring from the Bushmanland in the Northern Cape to the Roggeveld and Nuweberg escarpments, extending to the Doring River and lower Olifants River valleys and as far east as the Little Karoo. Our study shows that this broad concept should be separated into two further species, one A. grandiflora occurring on the Roggeveld escarpment and the other A. linearis (see below) for populations from the Bushmanland to the Little Karoo, therefore restricting A. vermiformis to the lower Olifants River valley. Austronea marginata and A. ecklonii also share the flat, elongated leaf with A. grandiflora . However, A. marginata clearly differs by the shorter and wider leaf, with margins thickened and densely and minutely retrorsely scabridulous, and the pale brown small flowers with tepals only ca. 5 mm long ( Manning & Goldblatt 2007), among other characters. Austronea ecklonii (= Drimia ligulata ) differs by the more numerous (up to 4), usually longer and wider leaves with thickened, papillate or colliculate margins and the small flowers as in A. marginata ( Manning & Goldblatt 2007) .

Additional material studied (paratypes):— SOUTH AFRICA. Northern Cape. Calvinia (3120): 20 miles E of Calvinia on Brandvlei-Williston road (- AC), photos of flowers 8 December 1970, photo of leaf 22 July 1971, M. Thomas s.n. ( NBG118025 !, PRE!) ; Sutherland (3220): NW of Sutherland, 2 km from Sutherland-Calvinia R354 road, on turn off to Bo-Visrivier (- AB), elev. 1264 m, 4 September 2011 (in leaf), M. Martínez-Azorín, A. Martínez-Soler & R. McKenzie MMA828a ( ABH59543 !) ; Sutherland (3220): ca. 24 km N Sutherland on R354 , roadside (- BA), elev. 1486 m, 5 November 2015 in flower, M. Pinter s.n. WW05291 ( ABH!) .

Figures

FIGURE 6. Distribution of Austronea species in southern Africa. A. densiflora Mart.-Azorín et al. (red circle), A. grandiflora Mart.- Azorín et al. (blue square), A. hispidoplicata Mart.-Azorín et al. (yellow triangle) and A. papillosa Mart.-Azorín et al. (green diamond).

FIGURE 7. Austronea grandiflora Mart.-Azorín et al. from NW of Sutherland (type locality), Northern Cape Province, South Africa, in leaf in the wild on 4 September 2011 and in flower in cultivation in Alicante (Spain) on 15 March 2014 corresponding to MMA828. A. Inflorescence; B. Flowers, frontal and dorsal views; C. Dissected flower in lateral view; D. Gynoecia, lateral views; E. Withered leaf at flowering time; F. Bulb and leaves, lateral views; G. Dissected bulb with leaf. Scale bars: A, F–G: 1 cm; B–E: 5 mm.