The identity of Albuca caudata Jacq. (Hyacinthaceae) and a description of a new related species: A. bakeri

Abstract The name Albuca caudata Jacq. has been widely misunderstood or even ignored since its description in 1791. After studying herbarium specimens and living populations in South Africa, plants fitting Jacquin´s concept of that species are found to be widely distributed in the Eastern Cape, mainly in the Albany centre of Endemism. Furthermore, some divergent specimens matching Baker´s concept of Albuca caudata are described as a new related species: Albuca bakeri. Data on typification, morphology, ecology, and distribution are reported for both taxa. Affinities and divergences with other close allies are also discussed.


Introduction
The genus Albuca L. is accepted to include about 60 species in recent treatments (cf. Speta 1998;Manning et al. 2002), although up to 131 when considered in a wider sense (Phillips 1951), with over 180 names available in its traditional sense (cf. IPNI 2011). Recent molecular works have however considered the circumscription of Albuca in quite different ways. On the one hand,  enlarged the tradi-tional concept of Albuca to include other genera such as Stellarioides Medik., Coilonox Raf., Trimelopter Raf. and Battandiera Maire, reaching a total of 110-180 species, and hence being very heterogeneous in morphology. On the other, Martínez-Azorín et al. (2011) recovered the traditional concept of Albuca on the basis of phylogenetic, morphologic and biogeographic evidences.
Taxa of Albuca in its traditional sense (cf. Martínez-Azorín et al. 2011) are distributed mainly in southern and eastern Africa, with only a few species extending to Ethiopia, Saudi Arabia and north of Chad and Nigeria. The only comprehensive revision of Albuca is that of Baker (1897Baker ( , 1898, who focused on South African and tropical African taxa. Recent accounts (cf. Müller-Doblies 1994, 1995, 2006) have greatly increased the knowledge of groups with nodding-flowers, namely A. subg. Albuca and A. subg. Falconera (Salisb.) Baker. However, information on groups with erect-flowers, e.g. A. subg. Mitrotepalum U. Müll.-Doblies (= A. sect. Branciona (Salisb.) J.C. Manning & Goldblatt), has remained almost unchanged from the late 19 th century, and is the focus of our current research (Martínez-Azorín et al. in press a, b). In addition, no identification keys are available for all currently accepted taxa of Albuca, most of which are still poorly known or in need of further studies (cf. Phillips 1926;Dyer 1947). For instance, Albuca caudata Jacq., a plant described from the Cape, has long been misinterpreted or even ignored. The study of herbarium specimens as well as natural populations of wild plants has revealed the existence of different biological entities to which the name A. caudata has been applied. In the present contribution, the name A. caudata is typified to warrant further usage in the sense it was originally published, and data are also presented to describe a new species to which that name was applied erroneously.

Materials and methods
Herbarium specimens from the following herbaria were studied: BOL, BNRH, GRA, J, K, KEI, KMG, NBG, NH, NU, PEU, PUC, UFH, WIND (acronyms according to Thiers 2011). Moreover, a detailed morphological study of both taxa was undertaken based on plants from natural populations. Authors of the cited taxa follow IPNI (2011).

results and discussion
Albuca caudata was described by Jacquin (1791) and later illustrated (Jacquin 1795) ( Fig.  1) after plants collected in "Promontorio bonae Spei", which "Apud nos in caldariis floret Decembri & Januario". The characters mentioned by Jacquin (1791) are: bulb roundish to ovate; leaves scarce, glabrous, linear-lanceolate, canaliculate, acute, with terete apex; stem weak and inclined; raceme lax, with patent pedicels; tepals white with green bands, the inner tepals with yellowish apices; all six stamens bearing anthers; and style clavate, thick and trigonous. Plants fitting this description are widespread in the Eastern Cape. They are usually easy to recognise by their solitary partially hypogeal bulbs, covered by short, papery, brown to grey scales that reach different heights, and their inclined unilateral racemes with all pedicels erect. However, a wide range in variation of vegetative and reproductive features can be observed, such as morphology of the scales of the bulb neck, leaf length and width, and flower disposition with regard to the inflorescence axis. A number of herbarium specimens labelled A. caudata differ significantly from Jacquin's description, but match Baker's concept of that taxon (cf. Baker 1869). These plants are characterized by their hypogeal roundish bulbs with fleshy outer tunics, all of them reaching the top of the bulb and ending into a long epigeal neck surrounded by transversally banded cataphylls. The particular characteristics of those collections, which were illustrated by Baker (1869) (Fig. 2), do not fit any of the known species of A. subg. Mitrotepalum. As differences with the typical A. caudata are remarkable, segregation at the species rank is here favoured and a new species is described for them. Information on both taxa is provided below. Description. Evergreen bulbous plants. Bulb mostly solitary and hypogeal, ovoid to oblong, up to 10 × 6 cm, usually with its wide basal plate elongated into a domed axis where the fleshy scales are attached; tunics fleshy, short and usually not reaching the top of the bulb, imbricate, persistent, papery grey or brownish in the upper part, sometimes with transversal prominent dark ridges, giving a brownish multiscaled appearance to the bulb in outline. Roots fleshy, thick and usually tuberose, white, numerous, up to 200 × 4 mm. Leaves 4-10, disposed in an apical rosette, linear-lanceolate, 15-120 × 0.5-2 cm, straight up and curving down when old, infolded, canaliculate, persistent, pale bright green to glaucous, glabrous, usually minutely papillate on nerves and margins, with a terete apex evident in young leaves. Inflorescence inclined, unilateral raceme, 11-40 cm long; peduncle 12-55 cm long; pedicels 3.5-9 cm long at base becoming smaller, up to 0.2-1 cm long near top, patent and being usually all erect; bracts ovate-lanceolate to triangular, long acuminate, 11-25 × 5-9 mm, papery white with brownish distant nerves that converge at the tips, much shorter than pedicels in the lower part of the inflorescence. Flowers erect; tepals white with a green median stripe 2-4 mm wide, sometimes with the tips yellowish; outer tepals oblong, 18-28 × 4-7 mm, apex slightly cucullate; inner tepals ovate, 15-24 × 4-10 mm, with apex strongly cucullate. Stamens all six bearing fertile anthers; outer anthers 1.5-2.5 mm long; inner anthers 3-4 mm long; outer filaments 10-16 × 1.5-2 mm, linear lanceolate to narrowly oblong, not pinched down; inner filaments 10-17 × 1.5-3 mm, linear oblong, wider and pinched in the lower half. Ovary oblong to obovate, up to 6-8 × 2-3.5 mm, stipitate, with prominent paraseptal crests that are divergent in the lower part and form three prominent ridges; style subobpyramidal or clavate, trigonous, up to 7-10 × 2 mm, stigma yellowish green. Capsule ovate, 14-20 × 10-14 mm, trigonous to subsphaerical in section, pale-brown when mature; valves splitting in the upper quarter. Seeds flat, c. 5-6 × 4-5 mm, dark brown to black, flattened and semidiscoidal, biseriate and horizontally stacked in each locule. (Fig. 3) Flowering time. September to November; capsules dehiscing at the end of November and December.

Albuca caudata
Habitat. Plants of A. caudata are often associated with bush-clumps, where the inclined inflorescence is supported by woody plants.
Distribution. Currently known from Addo in the west to Grahamstown in the east, below 600 m, with an outlying population as far inland as Somerset East, reaching 900 m (Fig. 4).
Diagnostic characters. Albuca caudata can be easily identified by its bulb mostly solitary covered by brownish papery scales usually disposed at different heights and bearing long thick tuberose roots, its long and narrow canaliculate or infolded leaves, its inclined raceme, with usually all pedicels patent and erect, giving a unilateral appearance to the inflorescence, and its white erect flowers with a median green stripe (Fig. 3).
Etymology. The specific epithet 'caudata' presumably refers to the rather pointed, tail-like leaves, although Jacquin did not specifically mention it (E.E.A. Gledhill, unpubl. ms. in NBG).
Relationships. The recently described Albuca batteniana Hilliard & B.L. Burtt (Hilliard and Burtt 1985) shares some morphological characters with A. caudata, such as the inclined scape bearing a horizontally arcuate inflorescence with erect pedicels, and the flower morphology. This species, however, differs in the coriaceous recurved much broader and flattened leaves, the longer tepals (30-42 mm long), and the structure of the bulb, being proliferous, epigeal, and composed by scales truncate at the top, disposed into a long domed axis and ending at different heights, without membranous neck (Table 1).
Distribution. from Jansenville to Alice and the Keiskamma river in the Eastern Cape, with two outlying populations near Calitzdorp in the Western Cape karroo (Fig. 6).
Diagnostic characters. Albuca bakeri can be easily identified by its solitary hypogeal fleshy bulb ending in an epigeal neck, covered by whitish transversally banded membranous cataphylls, giving a conspicuous zebra banding pattern (Fig. 5). Moreover, its erect and helicoidal raceme with white and green erect flowers, and the smaller seeds (c. 4-5 × 3-4 mm), separate it from A. caudata.
Etymology. Name honouring John Gilbert Baker (1834Baker ( -1920, a leading expert on monocotyledons, who worked at the Royal Botanic Gardens, Kew, and was the keeper of the herbarium K. Relationships. No other Albuca with erect flowers have been described with the characteristic long, thin, zebra banded bulb neck of A. bakeri. The closest species appears to be A. caudata, though the structure of the bulb and inflorescence clearly distinguish them (Table 1).
Observations. The peculiar zebra banded cataphylls of A. bakeri are similar to those found in some other groups of Hyacinthaceae. As pointed out by Müller-Doblies and Müller-Doblies (1981) Some morphological variation has been found within A. bakeri. Some individuals from Janseville and Port Elizabeth have a slightly setose bulb neck with the characteristic transversally banded membranous cataphylls of this species. Other specimens from Grahamstown and Port Elizabeth showed somewhat proliferous bulbs, resulting in a small clump of plants growing together, and with shorter scales not so markedly banded.
When Baker (1897) described and illustrated his concept of A. caudata (Fig. 2), he mentioned: "Bulb two to three inches thick, round or oblong, crowned as in the preceding [A. fastigiata Dryand.] with brown fibres. Leaves about a foot long, four lines broad, more rigid than in the preceding, clasping the stem at the base and more or less concave on the face upwards, and keeled on the back". This description is vague and inaccurate, since the illustration he presented did not show "fibres" at all, and no specific comments on the transversal banding of the upper scales of the bulb were made. However, when Baker reconsidered A. caudata in later works, his previous concept was changed to "Bulbus globosus 2-3 poll. crassus viridis apice squamosus" (Baker 1872), or "bulb globose, 2-3 in. diam.; tunics not splitting into fibres at the top" (Baker Thiers B (2011) Index Herbariorum: A global directory of public herbaria and associated staff.