Stellarioides exigua Mart.
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publication ID |
https://doi.org/ 10.11646/phytotaxa.204.2.4 |
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persistent identifier |
https://treatment.plazi.org/id/039E2E7A-FFF3-FFCB-FF0C-FB320A89FDDA |
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treatment provided by |
Felipe |
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scientific name |
Stellarioides exigua Mart. |
| status |
sp. nov. |
Stellarioides exigua Mart. View in CoL -Azorín, M.B.Crespo, A.P.Dold, M.Pinter & Wetschnig sp. nov. ( Figs. 1−5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )
Planta notabilis ob folia filiformia, capsulas anguste ovatas et semina perparva valde diversa et facile distinguitur. A S. arida cujus habitum similem differt quoque bulbi collo reliquis emarcidis basibus foliarum papiraceis destituto et inflorescentiis paucifloris brevioribusque. A duabus S. tenuifolia (sensu lato) et S. longebracteata etiam discrepat praecipue statura valde minore, bulbo non prolifero, hypogaeis pediculatis basalibus bulbillis (ut in priore) vel epigaeis apicalis bulbillis (ut in posteriore) carente, foliis multo angustioribus atque inflorescentiis paucifloris brevioribusque.
Type: — SOUTH AFRICA. Eastern Cape. Fort Beaufort (3226), north of Fort Beaufort, ca. 1 km from entry to Mpofu Nature Reserve (− DA), open overgrazed land with scattered Acacia karroo , 486 m of elevation, 28 November 2010, M. Martínez-Azorín & A. Martínez-Soler MMA539 (holotype GRA!, isotypes ABH!, K!).
Herbaceous perennial plant, 6 − 15(− 20) cm tall. Bulb hypogeal, not proliferous, ovoid to spherical or slightly depressed, 18 − 25 × 13 − 26 mm, with pale brown membranous thin outer tunics, with absent or very short (up to 2 cm long) hypogeal neck, lacking or with scarce and very small papery leaf bases. Roots fleshy, white, branched, 20 − 40 × 1 − 2 mm. Leaves 2 − 7 per bulb, synanthous, suberect in the basal portion and usually spreading-flexuose above, filiform, subterete, slightly canaliculated on the adaxial side, free from the base and not clasping the stem above the ground, 5 − 15 × 0.1 − 0.15 cm, dark green somewhat glaucous. Inflorescence an erect to slightly flexuose raceme with 5 − 12 flowers, 2 − 6 cm long, usually 2 − 3 inflorescences appear per bulb in different stages of development, each bearing buds, flowers or capsules coetaneously; pedicels 3 − 5 mm long, suberect, erect and slightly elongating in fruit; peduncle 3 − 12 cm long, erect to slightly flexuose; bracts narrowly ovate-lanceolate to subtriangular, long acuminate, 3 − 5 × 1.5 − 2 mm, membranous, white with a central green band and white basal auricles at anthesis, papery, white with rusty-reddish central nerve after anthesis, longer or equalling the pedicels at anthesis and slightly shorter in fruit. Flowers suberect, stellate; tepals almost free from the base, white with a green longitudinal stripe ca. 0.5 − 1 mm wide and visible on both sides that becomes rusty-reddish when withered; outer tepals oblong-lanceolate, 6 − 7 × 2 − 3 mm; inner tepals ovate-lanceolate, 5.5 − 6.5 × 2 − 2.7 mm. Stamens monomorphic, suberect to spreading; filaments narrowly ovate-lanceolate, tapering in the upper half, 4 − 5 × 1 − 1.5 mm, inner ones slightly wider, rarely with small lobes in the middle; anthers all similar, dorsifixed, dehiscing by longitudinal slits, 0.8 − 1.3 mm long, cream coloured before dehiscence and pinkish after pollen release. Ovary ovate-oblong, green, 2.5 − 3 × 1.5 − 2.5 mm; style columnar, white, erect, 2 − 2.5 × 0.5 mm; stigma trigonous, papillate. Capsule narrowly ovate-lanceolate, 5 − 7 × 4 − 4.5 mm, tapering to the apex, acute, trigonous with blunt edges in section; valves splitting in the upper quarter. Seeds flattened, mostly D-shaped, 1 − 1.8 × 0.8 − 1.2 mm, dark brown to black, biseriate and obliquely stacked in each locule, with puzzle-like epidermal cells of the testa.
Etymology:—The name refers to the small size of the new species, the smallest one known to date in Stellarioides (exiguus, -a, -um = small, weak, feeble).
Biology:—The flowering period of Stellarioides exigua spans from late spring and summer in South Africa, between November and February. This species usually produces up to 3 inflorescences per bulb that appear in different stages of development, each bearing buds, flowers or capsules at once. This behaviour allows the species to extend its reproductive span.
Distribution:— Stellarioides exigua is known from five main areas in the Eastern Cape Province of South Africa, from the Aloes Reserve, west of Port Elizabeth in the west, to the Pirie Mission (west of King William’s Town) in the east and near Sterkstroom ( Fig. 6 View FIGURE 6 ).
Habitat:— Stellarioides exigua grows in open grassland, thicket or karroid vegetation. Two populations were found in localities within the Albany Thicket Biome. The one from the surrounds of Fort Beaufort was found in a patch of Eastern Cape Escarpment Thicket (AT13) while the other, from the Aloes Reserve, east of Port Elizabeth, is confined to a patch of the Sundays Thicket AT6). These regions show a non-seasonal rainfall with a slight optimum in March and October/November, and the MAP (Mean Annual Precipitation) ranges from 190 and 700 mm and having 3 − 35 days of frost per year. Two populations were found in the Grassland Biome: one from the surrounds of Sterkstroom is confined to Queenstown Thornveld (Gs16) while the population from south of Fort Beaufort founds its habitat in Bedford Dry Grassland (Gs18). These areas show a bimodal rainfall occurring in spring and late summer, with MAP ranging from 310 − 640 mm and having 3 − 58 days of frost per year. The population from Pirie Mission grows in the Savanna Biome (Bisho Thornveld SVs7). This region shows a summer rainfall with some rain in winter, the MAP ranges from 500 − 900 mm and has infrequent frost. Finally, the population west of Riebeeck-East occurs in the Nama-Karoo Biome (Albany Broken Veld NKl4). This region shows a bimodal rainfall with main peak in March and secondary peak in November, the MAP in this locality is about 290 mm, with a low incidence of frost. The vegetation type nomenclature and the climatic data follow Mucina & Rutherford (2006).
studies of wild and cultivated living material and herbarium vouchers.
Taxonomic relationships:— Stellarioides exigua is easily identified by the small general size; the filiform, free leaves; the small narrowly lanceolate capsules and the small seeds ( Table 1). This new species can be easily distinguished from S. arida and S. tenuifolia by the shape and size of capsules and seeds alone, but other characters also support its independence ( Table 1).
Additional specimens examined (paratypes):— SOUTH AFRICA: Eastern Cape Province. Queenstown (3126): Queenstown, 60 km NW on Sterkstroom Rd. (− DA), open farmland, elevation 1500 m, 4 April 1995, A.P. Dold 1595 (GRA!) ; Fort Beaufort (3226): north of Fort Beaufort, ca. 1 km from entry to Mpofu Nature Reserve (− DA), open overgrazed land with scattered Acacia , elevation 486 m, 28 November 2010, M. Martínez-Azorín & A. Martínez-Soler MA539 (GRA!) ; Fort Beaufort (3226): on dry hill south of Fort Beaufort (town) amongst grass (− DC), common in small area, December 1925, R.A. Dyer 238 (GRA!) ; Stutterheim (3227): Natal, C.P. [Cape Province] Pirie [Mission] [King William’s Town] (− CC), November 1892, T.R. Sim 1094 (NU! 25690) ; Port Elizabeth (3325): Aloes Reserve, near Redhouse (− DC), dry vlei opening in thicket, elevation 40 m, 27 November 2009, M. Martínez-Azorín, A.P. Dold & A. Martínez-Soler MA48 (GRA!) ; Port Elizabeth (3325): east of Port Elizabeth, Aloes Reserve , above Amsterdamhoek (− DC), dry stony open places in thicket vegetation, elevation 40 m, 24 January 2010, M. Martínez-Azorín, A. Martínez-Soler & M.B. Crespo MA106 (GRA!) ; Port Elizabeth (3325): between Kommadagga and Riebeeck-East (− BB), road side, in sandy soils in karroid vegetation, elevation 521 m, 30 January 2010, M. Martínez-Azorín, A. Martínez-Soler & M.B. Crespo MA112 (GRA!) .
Note:—The herbarium collection Dyer 238 (GRA) from Fort Beaufort in the Eastern Cape was originally identified as “ Ornithogalum ”. A later determinavit label by F.M. Leighton reads “ O. subulatum Bak. forma?” and a second determinavit label by A.A. Mauve [= A.A. Obermeyer] states “ Ornithogalum juncifolium Jacq. ” These two opinions by Leighton and Obermeyer refer to species of Nicipe Rafinesque (1937: 54) , a genus that includes about 50 taxa related to Ornithogalum juncifolium Jacquin (1797: 46) (cf. Martínez-Azorín et al. 2011, 2014b, IPNI 2014). The adscription of Dyer’s collection to Nicipe is most probably based on the filiform leaves and small flowers, typical characters of taxa of Nicipe . However, Nicipe clearly differs from the Stellarioides species by distinct flower, fruit and seed characters, as detailed in Martínez-Azorín et al. (2011, 2014b). Furthermore, a note by R.A. Dyer attached to his herbarium sheet includes a morphological description of the plant and begins as follows: “R.A. Dyer 238; Ornithogalum patersonae Schonl. n. sp.?”. This indicates that Dyer already realized that it represents an undescribed species. We were not able to trace any specimen collected by T.V. Paterson and annotated by S. Schonland that could explain the cited note by Dyer attributing the new species to Schonland. As the name Ornithogalum patersonae sensu Dyer was never published (cf. IPNI 2015), not to be mistaken with the combination Ornithogalum patersoniae ( Schönland 1910: 442) J.C. Manning & Goldblatt in Manning et al. (2004: 550) (≡ Albuca patersoniae Schönland 1910: 442 ), a new species is here described.
Uncertain collections:— Obermeyer (1978) commented on O. tenuifolium subsp. aridum : “The following collections from the Transvaal Highveld are very close to subspecies aridum but are much smaller in size and do not produce a distinct neck. They appear to be paedogenic forms not yet deeply embedded in the soil”. The study of some herbarium collections from the North West and Gauteng Provinces of South Africa (see below) revealed that they approach in general the morphology Stellarioides exigua . However, we were not able to study mature capsule and seed morphology, and therefore we prefer not to include them in the new species until those characters are studied. SOUTH AFRICA: North West Province. Zeerust (2526): Panfontein Reserve (− DD), on edge of “pan” in grassveld, rare, 8 January 1953, W.J. Louw 2075 (PCU! Goosens herbarium 5028); Potchefstroom (2627): Potchefstroom, Haaskraal (− CC), 8 December 1949, W.J. Louw 1776 (PCU! Goosens herbarium 5024); Bloemhof (2725): Boskuil, Wolmaranstad (− BD), elevation 4200 ft., April 1929, J.D. Sutton 703 (PCU! Goosens Herbarium 5057). Gauteng. Johannesburg (2628): Gauteng, Heidelberg District, Heidelberg, 47 km SSE of Heidelberg, Kalkspruit (− CB), elevation 1520 m, 15 November 1959, J.P.H. Acocks 20827 (J091824!).
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