Helmet orchids
A small genus with approximately six species in Australia. These tiny terrestrial orchids grow in small groups usually with a very low proportion of plants flowering. The flowering plants have a single oblong to ovate shaped ground-hugging leaf, with a single nodding fleshy flower arising at the leaf base. A stalked hood-like dorsal sepal and the labellum dominate the small reddish, purplish flower, which is 0.5-1 cm in width. The thin, greatly reduced, whitish structures of the lateral sepals and petals cling to the labellum’s outer surface. The tubular labellum with ridges has two open-ended auricles at the base and a beak-like opening at the apex. The slender column is completely enclosed within the labellum. Anzybas are dormant in the summer, flowering in winter and spring. It occurs throughout all Australian states except the Northern Territory.
Similar Genera
Corybas
Significant Generic Characters
Deciduous terrestrial; leaf single, about as long as wide, epigeous; flower single, tubular, sessile, resupinate; dorsal sepal long-clawed; lateral sepals and petals adherent to the labellum; labellum tubular throughout, the upper margins fused, with an apical opening subtended by a beak-like platform; auricles open-ended; calli multiseriate, acicular, in one or more median rows on the ventral surface of the labellum; column elongate, lacking a swollen ventral pad.
Size and Distribution
A genus of c. 6 species restricted to Australia and New Zealand. In Australia the genus is most diverse in southern parts but occurs sporadically on the east coast, extending north to southeastern Queensland. Latitudinally in eastern Australia Anzybas is distributed from about 28°12' S on Mt Maroon in Queensland to about 43°30' S in southern Tasmania. State occurrence: Queensland, New South Wales, Tasmania, Victoria, South Australia, Western Australia.
Ecology
Species of Anzybas are deciduous terrestrial orchids that grow in small loose clonal groups or clonal colonies. Most species occur in coastal and near-coastal lowland areas but Anzybas montanus grows at about 900 m altitude on parts of the McPherson Range. Habitats where these orchids grow include heathland, open forest and seasonally inundated swampy sites.
Biology
Pollination: Species of Anzybas are pollinated by microdipterans of the family Mycetophilidae. These tiny insects may be attracted to the flowers by fungus-like odours, although that is uncertain. At least 2 species of Anzybas (Anzybas montanus and an undescribed species) are autogamous. Apomixis is unknown in the genus.
Reproduction: Reproduction in Anzybas is by seed and all species produce daughter tubers as well. This results in the formation of clonal colonies that can be relatively extensive or consist of just a few plants. Seed dispersal occurs 8-12 weeks after pollination. After pollination the peduncle thickens and elongates prior to seed dispersal.
Seasonal Growth: Anzybas plants are dormant over summer, surviving as small fleshy tubers and avoiding the extremes of heat, low humidity and dryness. Dormant tubers sprout in autumn and winter. In all species the buds emerge along with the leaves. Leaf expansion continues after flowering.
Flowering: Species of Anzybas flower in winter and spring.
Hybrids: Natural hybrids are unknown in Anzybas.
Fire: Species of Anzybas grow in habitats that are subject to summer fires. These orchids generally suffer a significant setback from hot summer fires and are not stimulated in any way.
Derivation
Anzybas is derived from the acronym for Australia and New Zealand and the last four letters of Corybas, a closely allied genus of orchids.
Botanical Description
Deciduous perennial geophytic herbs, sympodial. Trichomes absent or reduced to papillae on some parts. Roots both filamentous and stolonoid. Tubers small, globose, paired, fleshy; replacement tuber formed at the end of a short dropper; daughter tubers formed at the end of horizontal lateral stolonoid roots. Subterranean axes, including stolonoid roots, with minute papillae, each with unicellular apical hairs. Stem erect, short, unbranched, terete, with membranous cataphylls at each node. Flowering and non-flowering plants vegetatively monomorphic. Leaf single, basal, epigeous, petiolate. Leaf lamina longer than wide, firm textured, flat, convolute in bud, hypostomatic, abaxially pellucid or with anthocyanin pigments; apex apiculate or mucronate. Venation anastomosing, the main veins uniting apically. Inflorescence terminal, 1–flowered. Peduncle fleshy, prominent, lacking sterile bracts. Pedicel absent. Floral bract foliaceous, small, semi-sheathing. Ovary elongate, incurved, ribbed, glabrous. Flowers resupinate, small, fungiform, dull coloured (reddish or purple), epedicellate, pedunculate, dominated by the dorsal sepal and labellum, usually nodding. Dorsal sepal free, much larger than the lateral sepals, with a long distinct basal claw, distally inflated and cucullate. Lateral sepals free, greatly reduced, much smaller than the dorsal sepal, filamentous. Petals free, greatly reduced, subsimilar to the lateral sepals or even smaller, usually clasping the labellum. Labellum free, attached by its base to the anterior column base, markedly dissimilar in size and shape to the sepals and petals, ecalcarate. Labellum lamina tubular throughout, firm textured, not lobed, the upper margins fused, with an apical opening that is subtended by a beak -like platform. Labellum base with a pair of open-ended, folded auricles. Callus consisting of acicular mulitiseriate calli clustered along a thickened midline. Nectar absent. Spur absent. Column lacking free filament and style, slender, much longer than wide, incurved near the apex, without a ventral pad. Column foot absent. Pseudospur absent. Column wings mostly fused to the column, the tips free. Anther terminal, 2-celled, persistent, basifixed, erect, not rostrate. Pollinarium present, consisting of pollinia attached directly to a viscidium. Pollinia 4, unequal, mealy, yellow; pollen grains in monads or tetrads. Viscidium dorsal. Stigma entire, concave. Rostellum dorsal, transverse. Capsule dehiscent, thin-walled, ribbed; peduncle elongated and thickened in fruit. Seeds numerous, light coloured, winged.
Taxonomy
Prior to its segregation at generic rank, based on morphological and molecular characters, (Jones et al. 2002), Anzybas was included as section Auriculata within Corybas (Van Royen 1979).
Nomenclature
Anzybas D.L.Jones and M.A.Clem., Orchadian 13(10): 442-443 (2002). Type species: Anzybas unguiculatus (R.Br.) D.L.Jones and M.A.Clem.
Corysanthes R.Br. sect. Steleocorys Endl., Gen. Pl. 218 (1837); Corybas Salisb. sect. Steleocorys (Endl.) P.Royen in Phanerogamarum Monographiae Tomus XVI: 20 (1983); Corybas Salisb. subgenus Steleocorys (Endl.) Szlach., Polish Bot. J. 46(1): 22 (2001). Type species: Corysanthes unguiculatus R.Br.
Corybas Salisb. sect. Auriculata P.Royen, Alp. Fl. New Guinea 2: 69 (1978). Type species: Corysanthes unguiculatus R.Br.
Infrageneric Taxa: No infrageneric taxa are recognised.
References
Johns, J. and Molloy, B. (1983). Native Orchids of New Zealand. A.H. & A.W. Reed, Wellington.
Jones, D.L., Clements, M.A., Sharma, I.K., Mackenzie, A.M. and Molloy, B.P.J. (2002). Nomenclatural notes arising from studies into the tribe Diurideae (Orchidaceae). Orchadian 13(10): 437-468.
Jones, D.L. (1991). New taxa of Australian Orchidaceae. Austral. Orch. Res. 2: 1-207.
Jones, D.L. (1998). Contributions to Tasmanian Orchidaceae - 1: Introduction and the genera Acianthus, Arthrochilus, ×Classodia, Calochilus, Corybas, Cyrtostylis, Dipodium, Dockrillia, Gastrodia, Leptoceras, Microtis, Pyrorchis and Townsonia, Austral. Orch. Res. 3: 1-15.
Moore, L.B. and Edgar, E. (1970). Flora of New Zealand, vol. 2. Government Printer, New Zealand.
Van Royen, P. (1979). The Alpine Flora of New Guinea. Volume 2. J.Cramer, Germany.