Stellarioides chartacea Mart., 2013

Martínez-Azorín, Mario, Crespo, Manuel B. & Dold, Anthony P., 2013, Stellarioides chartacea (Hyacinthaceae, Ornithogaloideae), a new species from the Eastern Cape Province in South Africa, Phytotaxa 85 (1), pp. 1-8 : 2-6

Stellarioides chartacea Mart. -Azorín, M.B.Crespo & A.P.Dold, sp. nov. ( Fig. 1 A–J )

Planta ob folia canaliculata angustaque, capsulas ovato-acutas et semina subdiscoidea ca. 3−4 mm longa ad S. aridam et S. tenuifoliam accedens , sed eis facile distinguitur collo bulbi reliquis emarcidis basibus foliarum chartaceis fuscisque obsito. A priore insuper tamen differt foliis minus numerosis (3−5), usque ad 12 mm latis (in illa 1−3 mm), collo bulbi plene epigaeo atrofusco costis transversalibus reliquarum foliarum pene conspicuis. A posteriore insuper discrepat bulbo non prolifero (in illa bulbillis longe pediculatis) in collum epigaeum elongatum producto reliquis foliarum chartaceis fuscisque vestito, et etiam foliis atroviridibus glaucescentibus.

Type: — SOUTH AFRICA. Eastern Cape: Noorsdoornkraal, ca. 50 km east of Jansenville, 528 m, 32º59´41"S 25º18´39"E, 12 October 2011, flowered ex hort. 25 November 2012 in Grahamstown , M. Martínez-Azorín & A.P. Dold MMA990 (holotype GRA!, isotypes ABH!, K!) .

Bulbous plants up to 70 cm tall. Bulb mostly hypogeal, not proliferous, ovoid to spherical or slightly depressed, 3−6 × 2−7 cm, with pale brown membranous to dark grey and somewhat leathery outer tunics, with a 3−12 cm long epigeal neck covered by dark brown papery leaf bases with prominent, sinuous, transversal ridges. Roots fleshy, narrow, white, up to 10 × 0.1−0.3 cm. Leaves 3−5, incurved-canaliculated to convolute, long sheathing the stem base, 13−40 × 0.4−1.2 cm, dark green somewhat glaucous. Inflorescence an erect raceme with 20−30 flowers, 8−14 cm long; pedicels 2−3 mm long, patent to erect-patent, of similar length from the base to the apex, erect and slightly longer in fruit; peduncle 24−55 cm long, erect; bracts ovatelanceolate, long acuminate, 7−15 × 2−3 mm, longer than pedicels, before anthesis membranous, white with a central green band, at anthesis papery, white with brown central nerves. Flowers patent; tepals white with a green longitudinal stripe ca. 1−1.5 mm wide and visible on both sides that becomes rusty-reddish when withered; outer tepals oblong-lanceolate, 7−7.5 × 3−3.5 mm; inner tepals ovate-lanceolate, 6.5−7 × 2.5−3 mm. Stamens monomorphic; filaments narrowly ovate-lanceolate, tapering in the upper half, 5−5.5 × 1.2−1.5 mm, inner ones slightly wider; anthers all similar, 0.8−1.2 mm long. Ovary ovate-oblong, green, 3−3.5 × 2− 2.5 mm; style narrow, white, erect, 2.5−3 × 0.7 mm; stigma trigonous-punctiform. Capsule ovate, 8−9 × 6−7 mm, apiculate, slightly trilobate to subsphaerical in section; valves splitting in the upper quarter. Seeds flat, ca. 3.5−4 × 2−2.5 mm, dark brown to black, flattened and semidiscoid, biseriate and obliquely stacked in each locule, with puzzle-like testa ( Fig. 1 ).

Biology:—It flowers in late spring and beginning of summer, from late November to December. Fruits appear in late December to January and dehisce in mid January.

Habitat:— Stellarioides chartacea grows in open grassland and karroid vegetation in Bhisho Thornveld near Grahamstown, Kowie Thicket northwest of Grahamstown and Sundays Noorsveld near Jansenville ( Fig. 2 ) (sensu Mucina & Rutherford 2006).

Distribution: —This species is only known from three localities over 100 km apart in the Cacadu District of the Eastern Cape Province of South Africa ( Fig. 3 ).

Diagnostic characters and relationships: — Stellarioides chartacea is easily identified by its 3−12 cm long epigeal neck of the bulb covered by dark brown papery leaf bases with prominent, sinuous, transversal ridges; the 3−5 glaucous, dark green, incurved-canaliculated to convolute leaves; and the ovate-apiculate capsules.

Stellarioides chartacea appears at first sight closely related to S. arida ( Obermeyer 1978: 362) Speta (2001: 173) and S. tenuifolia based on the narrow canaliculated leaves; ovoid-acute capsule and semidiscoid seeds of ca. 3−4 mm long. Diagnostically, S. tenuifolia differs from S. chartacea by the proliferous bulb with long pediculate bulbils and the absence of a neck covered with papery leaf bases ( Table 1). Regarding S. arida , it differs from S. chartacea by the numerous, filiform leaves of 1−3 mm wide towards the middle, and the partially hypogeal neck covered by translucent, white to pale brown papery leaf bases with darker transversal ridges ( Table 1).

Although as many as 18 synonyms were included in S. tenuifolia subsp. tenuifolia (as O. tenuifolium subsp. tenuifolium ) by Obermeyer (1978), and defined as a morphologically extremely variable taxon, none of the described taxa in the genus show the combination of characters that define S. chartacea (cf. Fig. 1 , Table 1). According to our current knowledge, S. chartacea is sympatric with both S. tenuifolia and S. arida , when those latter taxa are treated in a wide sense. However, further studies are being undertaken to delimitate the taxonomic boundaries of those species complexes and the taxonomic value of their synonyms.

The presence of papery leaf bases has also been used in other closely related genera as key characters for taxa description, such as Albuca bakeri Mart. -Azorín & M.B.Crespo in Martínez-Azorín et al. (2011b: 12) and A. annulata Mart. -Azorín & M.B.Crespo in Martínez-Azorín et al. (2011c: 696) (cf. also Martínez-Azorín et al. 2011c), in which the papery leaf remains covering the stem bases were erroneously referred to in both cases as cataphylls.

Etymology:—Named after the presence of the papery leaf bases that surround the neck of the bulb (Chartaceus, -i = papery)

Conservation status:—From our known records, it is endemic to the Cacadu district in the Eastern Cape Province. In all localities, subpopulations were not large, with fewer than 10 individuals seen.

Figures

FIGURE 1. A–J. Stellarioides chartacea Mart.-Azorín, M.B. Crespo & A.P. Dold (holotype: Eastern Cape, Noordoornskraal, ca. 50 km east of Jansenville, M. Martínez-Azorín & A.P. Dold MMA990): A. Flowering plant. B. Inflorescence C. Dissected flower, outer tepals and stamens above, inner ones below, and gynoecium. D. Fruiting raceme. E. Capsule, apical view. F. Capsule, transversal sections. G. Dehiscent capsule. H. Seed. I. Leaf and transversal sections of leaves. J. Bulb with neck covered by papery leaf bases. Scales A–G, I–J: 1 cm; H: 5 mm.

FIGURE 2. Stellarioides chartacea Mart.-Azorín, M.B. Crespo & A.P. Dold in habitat at the type locality.

FIGURE 3. Known distribution of Stellarioides chartacea Mart.-Azorín, M.B. Crespo & A.P. Dold in South Africa.