Ornithoglossum pulchrum ( Colchicaceae : Colchiceae ) , a new species from southern Namibia

We describe a new species in the sub-Saharan genus Ornithoglossum Salisb. from southern Namibia. Ornithoglossum pulchrum from near Aus, is remarkable in having bright to dark pink flowers, a feature previously unknown in the genus. The perigone is almost concolorous apart from a contrasting, pale yellow nectary region, narrowly outlined with darker red, near the base of each tepal. The undulate leaves together with the long filaments, which are nearly as long as the tepals, suggest a relationship with O. undulatum, a widespread species in the western parts of southern Africa, and O. zeyheri from Namaqualand and the northwestern Cape. * Compton Herbarium, South African National Biodiversity Institute, Private Bag X7, 7735 Cape Town. E-mail: d.snijman@sanbi.org.za. ** Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden. *** P.O. Box 193, Windhoek, Namibia. E-mail: manfam@iafrica.com. na. MS. received: 2011-03-15. 232 Bothalia 41,2 (2011) erecto-patent pedicels 20–35 mm long, actinomorphic, ± widely campanulate, ± 40 mm diam.; tepals equally spreading, 27–32 × 4–5 mm, claw tubular-flattened, ± 4.0 × 1.5 mm, blade lanceolate, faintly 7–9-veined, slightly canaliculate, bright to dark pink, with a pale yellow nectary region narrowly outlined with darker red, becoming paler with age; nectary concave, widemouthed, ventral margin simple. Stamens slightly spreading; filaments straight, slightly curved distally, ± filiform but slightly thickened in proximal half, 25–28 mm long, uniformly dark pink; anthers oblong, 2.5 × 0.5 mm, slightly curved, dull yellow. Ovary oblong-globose, 5.0 × 3.5 mm, dark pink; styles free from base, spreading, straight proximally, slightly curved distally, ± 25 mm long, dark pink; stigma capitate, minutely papillate. Capsule elliptical-oblong, shortly and bluntly lobed, 7 × 4 mm (when immature but not known when mature), erect, coriaceous. Seeds unknown. Flowering time: June to early Aug. Figures 1; 2. Distribution and ecology: Ornithoglossum pulchrum is currently known from just one locality in the pro-Namib, a broad, undulating plain in southern Namibia (Figure 3). The species has been recorded in ephemeral watercourses from the uplands near Aus, which lie just below the inland escarpment, at approximately 1 380 m. The plants grow in coarse gravel, close to gneiss outcrops of the Namaqua Metamorphic Complex. Lying on the border of the winter and summer rainfall zones, Aus has bimodal rainfall, averaging 85 mm per year. Most rain falls in late summer (January to April) with a second, lower peak in June (Pallett 1995). Precipitation also occurs in the form of occasional fog which moves in from the coast, as well as rare snowfalls. Winds in the region are a powerful climatic force which can severely limit plant growth. Like most other Ornithoglossum species from southern Africa’s winter rainfall region, O. pulchrum flowers in winter, usually from mid to late June into August. B A B A FIGURE 1.—Ornithoglossum pulchrum. A, plant in habitat showing sheathing, undulate leaves and compact inflorescence; B, detail of campanulate flower showing long stamens and six large, concave nectaries each with a simple margin near base of tepals. Photographs: C. Mannheimer. FIGURE 2.—Ornithoglossum pulchrum. A, type specimen, Mannheimer CM2710 (WIND); B, specimen on left shows shallowly bilobed corm, specimen on right shows undulate, crispulate-edged leaves and young, upright capsules, Mannheimer CM4004a (WIND). Scale bars: A, B, 100 mm. Bothalia 41,2 (2011) 233 Diagnosis and relationships: Ornithoglossum pulchrum is distinguished by its flowers, which are suberect to spreading in a compact raceme that barely exceeds the leaves, and in which the ± filiform filaments are almost as long as the tepals. The flowers are easily distinguishable from those of other Ornithoglossum species by their bright to dark pink colour (47C, 48C in R.H.S Colour Chart 1966). This colouring is almost unbroken apart from a pale yellow patch, narrowly outlined with dark red, near the base of each tepal in the region of the nectary. O. pulchrum shares the character of undulate, crispulate-edged leaves with four other taxa in the genus, viz. O. undulatum, O. gracile B.Nord. and O. zeyheri B.Nord., and also O. parviflorum var. namaquense B.Nord. Compared with the floral characters, however, this vegetative feature is of less taxonomic importance, as quite plane-edged leaves are known in some populations of O. undulatum (Nordenstam 1979, 1982). Nevertheless, the undulate leaves together with the long filaments, which nearly equal the length of the tepals, suggest a relationship with both O. undulatum, a widespread species in the western parts of southern Africa, and O. zeyheri which is confined to Namaqualand between the Steinkopf region and the lower Olifants River Valley. O. undulatum differs from O. pulchrum in its markedly asymmetric flowers in which one or two tepals point downwards and the other tepals flare upwards at anthesis. These are slightly smaller than those of O. pulchrum (16–30 × 2–5 mm vs 27–32 × 4–5 mm) and are bicoloured, white in the centre with reddish purple tips. In contrast, the flowers of O. pulchrum are actinomorphic and campanulate, features that are shared with O. zeyheri. Unlike O. pulchrum, however, this species has few and inconspicuous flowers which are typically produced in May, with tepals that are short and narrow (12–15 × 1–3 mm) and coloured pale greenish with a purplish tinge towards the base and tip. The regular symmetry of the flowers of O. pulchrum prevent possible confusion with any other species from southern Namibia even in the early fruiting stages, since its withered tepals remain evenly spread around the developing suberect to spreading capsule, unlike those of O. undulatum which are distinctly reflexed from a markedly down-turned capsule. Both O. zeyheri and O. undulatum share a simple-margined nectary with O. pulchrum, although this feature is variable in O. undulatum, sometimes taking the form of an entire or bifid lobe. Ornithoglossum pulchrum has only been collected twice so far, once when in flower and again in the early stages of fruiting. As yet, mature fruits and seeds are not available for comparison with other species. Species from other families that are narrowly endemic to the Aus area are Moraea graniticola Goldblatt (Iridaceae) and Oxalis ausensis R.Knuth. (Oxalidaceae), both geophytic herbs, and the succulent shrub Juttadinteria ausensis (L.Bolus) Schwantes (Aizoaceae). M. graniticola and J. ausensis flower only after winter rain and when temperatures begin to rise. O. ausensis is one of four autumn-flowering Oxalis species in the vicinity of Aus.


INTRODUCTION
Ornithoglossum Salisb. is a small, sub-Saharan genus in the family Colchicaceae (Nordenstam 1998).All but one of the eight species recognized by Nordenstam (1982) are concentrated in the western half of southern Africa, mostly in the winter rainfall region.Only O. vulgare B.Nord. is found in southern Africa's eastern parts and as far north as East Africa.Previously the genus was placed in the tribe Iphigenieae (Buxbaum 1936), but in a new classification, based on an analysis of molecular data of the family, the genus now falls within the tribe Colchiceae, together with Colchicum L., Gloriosa L., Hexacyrtis Dinter and Sandersonia Hook.(Vinnersten & Manning 2007).
Considering its small size, the genus shows remarkable diversity in floral morphology.The perianth is actinomorphic or zygomorphic in form and coloured cream to attractive yellow, green, brown or purple, sometimes almost black, and often bicoloured.In species such as Ornithoglossum undulatum Sweet, the flowers are large, showy and sweetly scented, but in O. parviflorum B.Nord.they are small, inconspicuous, dull and unscented (Manning et al. 2002).Other variable features are the shape of the nectaries on the basal part of the tepals and the length and thickness of the filaments.Several micromorphological differences in the pollen and seeds also help to distinguish groups of species.All the species are reported to be highly toxic to stock due to their colchicine-type alkaloids, which accounts for their common name 'slangkop' (Watt & Breyer-Brandwijk 1962).

Ornithoglossum pulchrum
Distribution and ecology: Ornithoglossum pulchrum is currently known from just one locality in the pro-Namib, a broad, undulating plain in southern Namibia (Figure 3).The species has been recorded in ephemeral watercourses from the uplands near Aus, which lie just below the inland escarpment, at approximately 1 380 m.The plants grow in coarse gravel, close to gneiss outcrops of the Namaqua Metamorphic Complex.Lying on the border of the winter and summer rainfall zones, Aus has bimodal rainfall, averaging 85 mm per year.Most rain falls in late summer (January to April) with a second, lower peak in June (Pallett 1995).Precipitation also occurs in the form of occasional fog which moves in from the coast, as well as rare snowfalls.Winds in the region are a powerful climatic force which can severely limit plant growth.Like most other Ornithoglossum species from southern Africa's winter rainfall region, O. pulchrum flowers in winter, usually from mid to late June into August.(Nordenstam 1979(Nordenstam , 1982)).Nevertheless, the undulate leaves together with the long filaments, which nearly equal the length of the tepals, suggest a relationship with both O. undulatum, a widespread species in the western parts of southern Africa, and O. zeyheri which is confined to Namaqualand between the Steinkopf region and the lower Olifants River Valley.O. undulatum differs from O. pulchrum in its markedly asymmetric flowers in which one or two tepals point downwards and the other tepals flare upwards at anthesis.These are slightly smaller than those of O. pulchrum (16-30 × 2-5 mm vs 27-32 × 4-5 mm) and are bicoloured, white in the centre with reddish purple tips.In contrast, the flowers of O. pulchrum are actinomorphic and campanulate, features that are shared with O. zeyheri.Unlike O. pulchrum, however, this species has few and inconspicuous flowers which are typically produced in May, with tepals that are short and narrow (12-15 × 1-3 mm) and coloured pale greenish with a purplish tinge towards the base and tip.The regular symmetry of the flowers of O. pulchrum prevent possible confusion with any other species from southern Namibia even in the early fruiting stages, since its withered tepals remain evenly spread around the developing suberect to spreading capsule, unlike those of O. undulatum which are distinctly reflexed from a markedly down-turned capsule.Both O. zeyheri and O. undulatum share a simple-margined nectary with O. pulchrum, although this feature is variable in O. undulatum, sometimes taking the form of an entire or bifid lobe.
Ornithoglossum pulchrum has only been collected twice so far, once when in flower and again in the early stages of fruiting.As yet, mature fruits and seeds are not available for comparison with other species.
Species from other families that are narrowly endemic to the Aus area are Moraea graniticola Goldblatt (Iridaceae) and Oxalis ausensis R.Knuth.(Oxalidaceae), both geophytic herbs, and the succulent shrub Juttadinteria ausensis (L.Bolus) Schwantes (Aizoaceae).M. graniticola and J. ausensis flower only after winter rain and when temperatures begin to rise.O. ausensis is one of four autumn-flowering Oxalis species in the vicinity of Aus.
FIGURE 1.-Ornithoglossum pulchrum.A, plant in habitat showing sheathing, undulate leaves and compact inflorescence; B, detail of campanulate flower showing long stamens and six large, concave nectaries each with a simple margin near base of tepals.Photographs: C. Mannheimer.

Ornithoglossum pulchrum (Colchicaceae: Colchiceae), a new species from southern Namibia
.A. SNIJMAN*, B. NORDENSTAM** and C. MANNHEIMER*** Colchicaceae, Colchiceae, new species, Ornithoglossum Salisb., southern Namibia, taxonomy ABSTRACT We describe a new species in the sub-Saharan genus Ornithoglossum Salisb.from southern Namibia.Ornithoglossum pulchrum from near Aus, is remarkable in having bright to dark pink flowers, a feature previously unknown in the genus.The perigone is almost concolorous apart from a contrasting, pale yellow nectary region, narrowly outlined with darker red, near the base of each tepal.The undulate leaves together with the long filaments, which are nearly as long as the tepals, suggest a relationship with O. undulatum, a widespread species in the western parts of southern Africa, and O. zeyheri from Namaqualand and the northwestern Cape.Compton Herbarium, South African National Biodiversity Institute, Private Bag X7, 7735 Cape Town.E-mail: d.snijman@sanbi.org.za.** Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden.