Three new species of Lachenalia (Hyacinthaceae: Massonieae) from Western and Northern Cape, South Africa

This is the sixth in a series o f papers on Lachenalia, towards a revision o f the genus. Three new species are described. L. lutea from the southwestern part o f the Western Cape, L. cernua from the southern Cape Peninsula and the Worcester Valley o f the Western Cape, and L. nardousbergensis from the Bokkeveld Plateau o f the Northern Cape, and the Nardousberge and Middelburg Plateaus o f the Western Cape.


INTRODUCTION
The horticulturally important and botanically diverse genus Lachenalia J.Jacq. ex Murray is endemic to south ern Africa and comprises 120 species of deciduous geophytes, almost all of which are winter growing (Duncan et al. 2005). The distribution of Lachenalia extends from southwestern Namibia into the western, southern, eastern and central parts of South Africa, and the cen tre of diversity is in the Worcester grid (3319), divided between the Succulent Karoo and Fynbos Biomes, in the mountains and valleys of the winter rainfall region of the Western Cape (Duncan 2005).
Species delimitation in Lachenalia is usually unam biguous, but in some instances there is gradation between species. Other species display extensive variation which has led to considerable taxonomic confusion due to over emphasis of minor morphological differences. Variation within a species occurs in several macro-morphologi cal characters such as overall plant size, leaf number, pedicel length, degree of stamen exsertion, flower size, flower colour and orientation, and flowering period. Variable species often display population stability in features such as bulb and flower shape, and seed mor phology; however, a number of species are exceedingly variable (Duncan et al. 2005).
In a cladistic analysis of morphological data, it was concluded that a number of evolutionary pressures have driven divergence of vegetative and floral characters in Lachenalia. The convergent adaptation to conditions of aridity appears to be the main reason for homoplasy in whole sets of vegetative characters, and similarly, the convergent modification of flowers to similar pollina tors is probably the main reason for homoplasy in whole sets of reproductive characters (Duncan et al. 2005).
The genus was last revised by Baker (1897) in which 42 species were recognized. The new species described here form part of a series of papers towards a revision of the genus (Duncan 1993, 1996, 1997, 1998, Duncan & Edwards 2002.
Etymology: the specific epithet lutea is named for the pale to bright yellow flowers.
History: the earliest known record of Lachenalia lutea is that of J.F. Solly (Solly sub PRE1J352) who col lected it in August 1915 at the foot of Sir Lowry's Pass east of Cape Town, where this species is common, and has been collected on numerous occasions. It has since been widely collected in the southwestern and southern parts of the Western Cape.
Diagnostic features and affinities: Lachenalia lutea has for many years been overlooked as a distinct taxon.
It belongs to the group of species having sessile, oblongcampanulate flowers with straight stamens, and most closely resembles L. arbuthnotiae. L. lutea is recognized by its dense inflorescence of suberect, heavily sweetscented, pale to bright yellow, oblong-campanulate flowers with spreading inner tepals that protrude well beyond the outer tepals ( Figures 1 A; 2). The outer tepals have bright green gibbosities, the inner tepals have suba cute apices and the stamens are usually included within the perianth or rarely slightly exserted. The sturdy peduncle is pale green or brownish green and may be plain or heavily marked with brownish purple blotches. The two leathery, lanceolate leaves are spreading to suberect and bright green or greenish magenta, with or without darker green or greenish magenta blotches on the upper surface. The globose seeds have a shiny black testa and a smooth, inflated strophiole.
The sim ilar oblong-campanulate flowers of Lachenalia arbuthnotiae are also heavily sweet-scented but are slightly curved and distinctly longer, with the inner tepals only slightly longer than the outer ones, and scarcely spreading. The inner tepal apices in this species are obtuse and undulate, and flower orientation is spreading to weakly suberect. It has much longer fila ments, 8-9 mm long, a much longer style, 9 mm long and its anthers emerge at the mouth of the perianth or are shortly exserted. The style protrudes conspicuously beyond the perianth as the ovary enlarges. Like those o f L. lutea, the seeds o f L. arbuthnotiae are globose with a shiny testa, but its sim ilar inflated. sm ooth strophiole is slightly longer. As in L. lutea, L. arbuthnotiae grows in colonies but is an altogeth er larger plant occurring in a completely different habitat, confined to the Cape Flats Lowlands from Wetton to Faure, in isolated coastal fynbos remnants in seasonally inundated, deep sandy soil (Duncan 1988a). The peak flowering period for L. arbuthnotiae is mid-September, whereas L. lutea generally flowers earlier, with a peak period from mid-August to early September.
Distribution and habitat: Lachenalia lutea occurs in the Fynbos Biome in the southwestern Cape, its dis tribution extending between Strand and Bot River, and Tulbagh to \ illiersdorp ( Figure 3). It usually occurs in stony, heavy clay soil in renosterveld, or rarely in sandy soil, and is found in a variety of habitats includ ing seasonally moist, low-lying flats and hills, and on shale bands of higher mountain slopes, growing as scattered individuals or in small groups of two to three plants within large colonies. It flowers particularly well following summer bush fires and is frequently seen growing in association with L. orchioides (L.) Aiton var. orchioides that flowers later in the season. L. lutea is still a common species across most of its range but its numbers have been much reduced by the establish ment of deciduous fruit orchards, and in recent years it has been greatly reduced on the clay flats near Somerset West, east of Cape Town, due mainly to industrial and housing development. Lachenalia cernua G.D. Duncan, sp. nov. Plantae 150-270 mm altae, bulbus globosus, 15-25 mm in diametro, folium solitarium, interdum 2, lanceolatum, patens, viride que immaculatum, vel in pagina superiore marroninum maculis plus atromarroninis, 110-260 x 10-28 mm, inflorescentia racemosa erecta vel suberec-ta, 30-100 mm longa, pedunculus pallide viridis macu lis marronino-purpureis, 60-130 mm longa, pedicelli suberecti, 2 mm longi, flores urceolati, tempore primo ad medio florendi deinde cemui, in fructo patentes, pal lide cremeo-flavi, perianthii tubum cyathiforme, 3 mm longum, tepali exteriora ovata, base obscure caerulei suffusi, gibbis flavo-viridibus, 6 -8 x 5 mm, tepala interiora obovata, trans tepalis exteriora bene exserta, carinis flavis, marginibus recurvatis, 11-12 x 5 mm. stamina trans perianthium breviter exserta, filamenta recta, alba, 11-13 mm longa, ovarium ellipsoideum, 4 x 3 mm, stylum rectum, album, 12 mm longum, capsula ellipsoidea, 9 -1 0 x 6 mm, semina globosa, 1.2 x 1.1 mm, strophiolo inflato, 1 mm longo. Deciduous, winter-growing geophyte 150-270 mm high. Bulb globose, shallow or deep-seated, 15-25 mm diam., white with several layers of membranous, dark brown outer tunics; cataphyll subterranean, translucent white, loosely surrounding lowermost portion of clasping leaf base, apex obtuse; clasping leaf base relatively long depending on depth of bulb, usually completely subter ranean, occasionally emerging slightly above ground level, 15-85 mm long, white, sometimes forming bulbils along subterranean margins. Leaves usually solitary, occasionally 2, spreading, narrowly lanceolate, weakly canaliculate, 110-260 x 10-28 mm, uniformly pale to dark green, or pale to dark maroon and sporadically or heavily marked with darker maroon blotches on upper surface. Inflorescence an erect or suberect, few-to manyflowered raceme 30-100 mm long, with a short sterile tip; peduncle erect or suberect, 60-130 mm long, pale green, slightly to heavily marked with dark maroon or maroonish purple blotches; rachis, 50-175 mm long, pale green, immaculate or heavily blotched with maroon or maroonish purple; bracts ovate in lower half of inflores cence, becoming lanceolate in upper half, 1-5 x 1-7 mm, translucent white; pedicels suberect, 2 mm long, white. Flowers urceolate, suberect in bud, cemuous from early to mid-flowering, becoming spreading at late flowering and fruiting stage, creamy white and pale yellow with green markings; perianth tube cup-shaped. 3 mm long, creamy white, occasionally tinged with dull blue in upper half; outer tepals ovate, 6-8 x 5 mm, creamy white or greenish yellow, occasionally tinged with dull blue at base, with a yellowish green gibbosity near apex; inner tepals obovate, protruding well beyond outer tepals, 11-12x5 mm, creamy white or greenish white with pale to dark yellow keels in upper half, apices slightly recurved. Stamens ± straight, subequal, exserted 1-2 mm beyond tip of perianth; filaments 11-13 mm long, white. Ovary ellipsoid, 4 x 3 mm, bright green; style straight, white, 12 mm long. Capsule ellipsoid, 9-10 x 6 mm, olive green. Seed globose, 1.2 x 1.1 mm, shiny black, with smooth, inflated strophiole 1 mm long. Flowering time: late September to mid-October. Figures IB; 4. Etymology': the specific epithet cernua is named for the slightly drooping orientation of its flowers during the early and mid-flowering stage.   Diagnostic features and affinities'. Lachenalia cer nua is a member of the group of species having small pedicellate, urceolate flowers with straight stamens, and includes L. peersii Marloth ex W.F.Barker, which it most closely resembles. L. cernua is recognized by its moderately dense inflorescence of urceolate, pale creamy yellow flowers that are cemuous during early and mid flowering, becoming spreading during late flowering and fruiting stage (Figures IB; 4). The inner tepals are creamy white or greenish white with pale to dark yellow keels in the upper half, and are well exserted beyond the outer tepals, with slightly recurved apices. The outer tepals are creamy white or greenish yellow, and have yel lowish green gibbosities. The stamens are exserted 1-2 mm beyond the tip of the perianth. The usually solitary leaf is narrowly lanceolate and spreading, and varies in colour from uniformly pale to dark green, to pale to dark maroon with scattered darker maroon blotches on the upper surface. The clasping leaf base is entirely subter ranean or occasionally slightly emerging above ground level, and the globose seeds have a shiny black testa and a long inflated strophiole. 1 mm long.
Lachenalia cernua resembles L. peersii in the shape of its urceolate flowers with the inner tepals protrud ing well beyond the outer tepals, but the latter has pure white, spreading flowers with included stamens, and inner tepals that are distinctly recurved at their tips. L. cernua has longer inner tepals and its flowers emit a weak, spicy scent, whereas those of L. peersii are strong ly carnation-scented. The peduncle of L. cernua is pale green and slightly to heavily marked with dark maroon or maroonish purple blotches, whereas the peduncle of L. peersii is always immaculate. L. cernua usually has a solitary, weakly canaliculate spreading leaf, often with dark maroon blotches on the upper surface, whereas L. peersii almost always has two, ± flat, lanceolate leaves that are always unmarked. The flowering period of the two species does not overlap as L. cernua starts flower ing in late September and ends in mid-October, whereas L. peersii starts flowering in late October. The flowers of L. cernua fade to dull red and become spreading during the fruiting stage, whereas those of L. peersii fade to dull pink and become suberect to erect at the fruiting stage. Both species have globose seeds with inflated strophioles 1 mm long. The two species are geographically well separated: L. cernua occurs on hillsides in the southern Cape Peninsula, the Worcester Valley and near Wolseley, whereas L. peersii is confined to flats and lower moun tain slopes along the southern Cape Atlantic coastline stretching from Betty's Bay to Caledon (Duncan 2003).
Diagnostic features and affinities: Lachenalia nar dousbergensis falls into the group of species having pedi cellate, oblong-campanulate flowers with well-exserted, deelinate stamens, and most closely resembles L. purpureo-caerulea Jacq. L. nardousbergensis is recognized by its usually distinctly inflated peduncle that is marked with large brownish purple blotches, and its many-flow ered. moderately dense raceme of nodding or spreading, pale to deep magenta, oblong-campanulate flowers with well-exserted. deelinate stamens, with the filaments deep magenta in the upper third ( Figures 1C; 6 ). Its two prostrate, broadly lanceolate, olive-green leaves have conspicuous longitudinal grooves along the upper sur face. and are covered with large, dark green, flattened, oval pustules. The leaves are partially or completely withered at flowering but remain green under cultivation if plants are kept well watered in late winter and spring. The flesh of the subglobose bulb is dark yellow and the bulb is surrounded by several layers of dark brown, outer tunics. Its globose, shiny black seeds have a rudimentary strophiole, 0 .6-0 .7 mm long.
The oblong-campanulate flowers of Lachenalia purpureo-caerulea differ from those of L. nardousbergensis in their deep purplish blue colour and in being larger and more widely flared, with rounded, recurved, deep purple inner tepal apices and a much shorter style 8 mm long and stamens 9-10 mm long. The peduncle of L. purpureo-caerulea is unmarked and non-inflated. and it has two bright green, prostrate lanceolate leaves densely covered with small green, dome-shaped pustules. Like those of L. nardousbergensis. the leaves of L. purpureocaerulea are partially or completely withered at flower ing in the wild and the two species are geographically widely separated. L. purpureo-caerulea having a highly restricted distribution in the Darling Mamre District of the southwestern Cape, occurring on sandy gravel flats in renosterveld. and flowering later in the season, from mid-October to mid-November (Duncan 1988b). Like those of L. nardousbergensis. the shiny black, globose seeds of L. purpureo-caerulea fall into the group having smooth, rudimentary strophioles.
Distribution and habitat: Lachenalia nardousber gensis has a limited distribution in the Fynbos Biome in the northwestern part of the Northern Cape and the northwestern part of the Western Cape, extending from the Bokkeveld Plateau at Nieuwoudtville. southwest to the Nardousberge Plateau southeast of Klawer, and southeast to the Middelburg Plateau at the northern end of the Cederberg ( Figure 5). The plants occur in areas of fairly level, high-lying ground, in deep red or yellowish brown sand, growing as scattered individuals or in small colonies in fynbos vegetation, among low succulent undergrowth or restios.