Stellarioides littoralis N.R.Crouch, D.A. Styles, A.J.Beaumont & Mart.

Crouch, Neil R., Martínez-Azorín, Mario, Beaumont, Angela J. & Styles, David A., 2014, Stellarioides littoralis (Asparagaceae, Scilloideae), a distinct new species from eastern South Africa, Phytotaxa 177 (5), pp. 261-268 : 262-265

Stellarioides littoralis N.R.Crouch, D.A. Styles, A.J.Beaumont & Mart. -Azorín, sp. nov. ( Fig. 1 A−M).

It differs from Stellarioides longibracteata in its smaller stature, in the production of bulbils attached to the bulb base by short, umbilical connectives (pediculate bulbils) instead of bulbils sessile from beneath the tunic and between scales, the leaves, spiralled at the tips, the inflorescence with flowers gathered in a terminal head-like cluster instead of an extended open raceme, the bracts much shorter and less obvious, and the smaller seeds. It differs from Stellarioides tenuifolia s. str. by the epigeal bulb, the flat, long linear-lanceolate leaves with spiral apices, not straight, thin and very long, and the short head-like inflorescences, not long and narrowly racemose.

Type: — SOUTH AFRICA. KwaZulu-Natal: Ramsgate, Erven 1215 and 1216, alt. 2 m, growing in colonies in shallow lithosols overlying sheetrock adjacent to the coastline, 30.898382ºS, 30.346502ºE, flowered ex hort. 16 November 2007 in Kloof , Durban , N . Crouch & D. Styles 1283 (holotype, BNRH) .

Perennial, rosulate, clustering plant, up to 30 cm tall. Roots white, terete, succulent and branched. Bulb globose or ovoid, 25–40 mm diam., usually appearing above ground, exposing green, live tissue with brown to grey, papery tunics, bulbils numerous, pediculate, attached to the basal plate of the mother bulb. Leaves 5–6, synanthous, sheathing at base, narrowly linear to narrowly lanceolate, 22–36 × 1–1.8 cm, emerald green, midvein and adjacent lamina faintly silvery green above, glabrous, soft, often flaccid and loosely spiralled, dying back from apex, tip with short terete appendix. Inflorescence a simple raceme, but flowers gathered in head-like terminal cluster, ca. 3 × 2 cm, immature buds, mature flowers and immature fruits occurring together, flowers 11–20, ascending ca. 40º from the horizontal, rachis lengthening during flowering and fruiting to 3.5–7.5 cm; peduncle terete, ca. 2.5 mm diam., 11–25 cm long. Bracts green-brown with membranous margins, turning brown and papery during fruiting, not pronounced in the bud stage, 2–2.3 mm wide at base, 7–9 mm long, lanceolate, abruptly narrowing near the base, apex acuminate, persisting during fruiting stages. Flowers small, cyathiform, 2–4 open at a time, ca. 9 mm diam., greenish white, lightly scented, closely packed; pedicels ca. 3 mm long, lengthening to ca. 8 mm in fruit. Tepals free, elliptic, tip slightly cucullate, pubescent, ca. 7–8 × 3.5–4 mm, midrib with a ca. 1.3 mm wide central band, pigment more prominent on abaxial surface, prominently 3-nerved above, margins white. Stamens adnate to tepal bases; filaments winged, ca. 5 mm long, inner ones narrower and shorter than outers; anthers versatile, dorsifixed, dehiscing by longitudinal slits, thecae linear, ca. 1.5 mm long, pollen orange-yellow. Pistil as long as stamens; ovary superior, 3-lobed, glabrous, ca. 3.5 mm long, bright sap- green; style columnar, 2 mm long, translucent-white; stigma small, truncate, minutely pubescent. Infructescence compact, capsules crowded in short, head-like raceme. Capsule globose, thin-walled, not beaked, ca. 9 × 6 mm, obtuse-trigonous. Seeds flattened, variously angled to D-shaped, 3–4 mm long, black. Chromosome number: unknown. Flowering time: October–December; Fruiting time: December–February. Figure 1 .

Distribution and ecology:—The new species is known only from the south coast of KwaZulu-Natal ( Figure 2 ) where a single population has been recorded to date with about two hundred individuals. The site is within 15 m of the Spring tide mark, with plants growing on shallow lithosols together with Albuca setosa Jacquin (1795: 20) , Crassula obovata Haworth (1819: 18) var. obovata and Delosperma lineare Bolus (1928: 143) . The vegetation type represents an ecotone of Subtropical Seashore Vegetation (AZd 4) and KwaZulu-Natal Coastal Belt (CB 3) ( Mucina & Rutherford 2006). The grass Stenotaphrum secundatum ( Walter 1788: 249) Kuntze (1891: 794) has largely overrun the littoral vegetation at the site, which is becoming increasingly transformed so threatening the survival of this new species. Plants have subsequently flowered in cultivation, from which the description and illustrations were prepared. Cultivated plants in both Pietermaritzburg and Kloof retained the morphology and size of the plant in natural conditions.

Etymology:— Littoralis = pertaining or related to the seashore.

Diagnostic characters and relationships:— Stellarioides littoralis shows a unique combination of characters within the genus. Its flat and spreading leaves, with epigeal photosynthetic bulbs are reminiscent of S. longibracteata . However, S. littoralis differs by the general smaller size, with bulbs up to 4 cm, the pediculate bulbils, the leaves spiralled at the apex ( Figure 3 ), the head-like inflorescence ( Figure 4 ), the shorter bracts and the smaller seeds ( Table 1). On the other hand, S. littoralis shares with S. tenuifolia the pediculate bulbils ( Figure 5 ) and the small seeds, however, the latter species differs by its mostly hypogeal bulb, long racemose inflorescences and the very narrow, canaliculated, and straight suberect leaves ( Table 1). None of the 18 synonyms included in Ornithogalum tenuifolium subsp. tenuifolium by Obermeyer (1978) shows the combination of characters found in S. littoralis . Consideration has been made of the possibility of S. littoralis being a hybridogenous taxon. However, neither putative parents ( S. tenuifolia and S. longibracteata ) were observed growing sympatrically at the type locality.

Figures

FIGURE 1. A–M. Stellarioides littoralis N.R.Crouch, D.A.Styles, A.Beaumont & Mart.-Azorín (corresponding to the holotype: N. Crouch & D. Styles 1283 BNRH): A. Flowering plant. B. Inflorescence. C. Bulbs producing pediculate bulbils, and with necks covered by papery leaf bases. D. Dissected flower, inner tepal and stamen above, outers below. E. Bract. F. Outer tepal. G. Inner tepal. H. Outer stamen. I. Inner stamen. J. Gynoecium. K. Immature capsule. L. Dehiscent capsule. M. Seeds. Scales A: 24 mm; B: 4.8 mm; C: 16 mm; D–J: 3 mm; K–L: 8 mm; M: 2.4 mm. Illustration by A.J. Beaumont.

FIGURE 2. Known distribution of Stellarioides littoralis N.R.Crouch, D.A.Styles, A.Beaumont & Mart.-Azorín in South Africa.

FIGURE 3. Leaves flat and spreading, often spiralled at the apex.

FIGURE 4. Raceme with flowers gathered in head-like terminal cluster, bracts not prominent at maturity.

FIGURE 5. Bulbils pediculate, attached to the basal plate of parent bulb.