JOURNAL of the ADELAIDE BOTANIC GARDENS AN OPEN ACCESS JOURNAL FOR AUSTRALIAN SYSTEMATIC BOTANY flora.sa.gov.au/jabg Published by the STATE HERBARIUM OF SOUTH AUSTRALIA on behalf of the BOARD OF THE BOTANIC GARDENS AND STATE HERBARIUM © Board of the Botanic Gardens and State Herbarium, Adelaide, South Australia © Department of Environment, Water and Natural Resources, Government of South Australia All rights reserved State Herbarium of South Australia PO Box 2732 Kent Town SA 5071 Australia © 2008 Board of the Botanic Gardens & State Herbarium, Government of South Australia J. Adelaide Bot. Gard. 22 (2008) 5–8 © 2008 Department for Environment & Heritage, Government of South Australia Prasophyllum laxum (Orchidaceae), a new leek-orchid species from southern Eyre Peninsula, South Australia Robert J. Bates C/- State Herbarium of South Australia, Plant Biodiversity Centre, P.O. Box 2732, Kent Town, South Australia 5071 E-mail: [email protected] Abstract Prasophyllum laxum R.J.Bates, a rare local endemic leek orchid from southern Eyre Peninsula, South Australia, is described as new and illustrations and a key to related South Australian species are provided. Introduction Prasophyllum laxum has been compared with P. A single collection at the State Herbarium of lindleyanum Rchb.f. (as P. aff. lindleyanum; Bates South Australia (AD) of an apparently undescribed 2006), mainly because of the sigmoid labellum, but that Prasophyllum from southern Eyre Peninsula, hundred of species is restricted to Tasmania and (mostly eastern) Koppio, section 212 (M.G.Clark 212) had long intrigued Victoria and has rigidly erect spikes with usually green the author but despite many searches on Southern Eyre and white, very neat flowers with the short labellum Peninsula from 1982 to 2002 no further plants were having strongly incurved margins, and the callus shortly located. pubescent. Members of the Clark family collected many other The nearest verified populations of P. lindleyanum are interesting orchids around their home near Koppio in many hundreds of kilometres away from Eyre Peninsula. the 1960’s including several other Prasophyllum species Prasophyllum lindleyanum also prefers cool moist not published at the time. The exact location of their P. woodland, mostly flowers in November and is stimulated laxum collection is not known. to flower by bushfires, whereas P. laxum prefers dry It was not until October 2004, while working with woodland, flowers mostly in early October and was Sarah Way on a three day survey of nesting habitats of badly affected by the 2005 Eyre Peninsula bushfires. the endangered Eyre Peninsula race of yellow-tailed Prasophyllum lindleyanum is not closely allied to any black cockatoo, that a large population of the orchid was South Australian forms. Plants from Western Victoria located on private property south-west of Koppio, about with pink tinged flowers, previously included under P. 10km from the Clark property. A suitable type collection lindleyanum (Backhouse & Jeanes 1995), have been was made and a photograph taken. determined by D.L.Jones (pers. comm.), Rouse (unpubl. The new species is a member of the suspected data). and Backhouse and Jeanes (2006) as belonging to apomictic group of species (Bates 1989b; van der Cingel an unpublished taxon with rigidly erect flower spikes 1989) of which Prasophyllum fitzgeraldii R.S.Rogers & and a short straight labellum. Maiden was the first South Australian species named. Jones (1998) described four eastern Australian For this reason the complex (of about fifteen taxa, some members of the P. fitzgeraldii complex, i.e. P. favonium unpublished) is often referred to as the P. fitzgeraldii D.L.Jones, P. perangustum D.L.Jones, P. secutum complex (Group 5 of Jones 2006); it includes P. D.L.Jones and P. taphanyx D.L.Jones, none of which pallidum Nicholls, P. goldsackii J.Z.Weber & R.J.Bates, are likely to occur in South Australia. He has not as yet P. fecundum R.J.Bates, P. occultans R.J.Bates and P. named any South Australian members of the complex. sp. Enigma (R.Bates 2350) in South Australia. Like P. Jones (2006, pp. 216–218) treated all published laxum all of these species have been observed growing species of the complex as Prasophyllum Group 5, except sympatrically with other members of the complex for P. goldsackii which was placed in his Group 4. Most without introgression, indicating genetic isolation. species are pictured, but not all correctly, e.g. the image As is usual for apomictic species, the flowers of on p. 216 captioned as P. fecundum is actually P. sp. the P. fitzgeraldii complex are very short lived, the Enigma (R. Bates 2350). ovaries swelling even before the flowers open and all The author has provided living material of most the capsules producing a large amount of seed without South Australian taxa of the P. fitzgeraldii complex to fertilization (Bates 1989b). At least one species of this D.L. Jones (Canberra), who, based on this material, has group, P. goldsackii, is cleistogamous. several South Australian leek orchids of the complex in 5 R.J. Bates J. Adelaide Bot. Gard. 22 (2008) Fig. 1. Prasophyllum laxum. a–b habit; c underground tuber; d–f flower:d front view; e side view; f rear; g–i labellum: g front view; h side view; i rear; j–o column, views from various angles. Scale: a–c 1 cm; d–f 2.5 mm; g–o 0.5 mm. R.J.Bates 64064. 6 J. Adelaide Bot. Gard. 22 (2008) New species of Prasophyllum (Orchidaceae) manuscript. These unpublished species are treated in Plants slender, pallid, to 30 cm tall, leaf and scape Orchids of South Australia (electronic version, 2006) as rather lax, leaf base green, scape and leaf of similar Prasophyllum sp. Enigma (R.J.Bates 2350), P. sp. Gum length. Leaf to 30 cm long and to 4 mm diam., narrow- Lagoon (P.J.Lang 1633) and P. sp. Bright shiny maroon cylindrical and tapering. Scape emerging from hollow (R.J.Bates 3040). leaf at a fistula set 10–20 cm above ground level, pale Jeanes & Backhouse (2006) discuss and illustrate green and shiny, to 4 mm diam., with no sterile bracts. three un-named taxa of the complex as P. aff. fitzgeraldii Flowers 5–20, irregularly arranged in a loose, typically 1 ‘Pink-lip Leek-orchid’, P. aff. fitzgeraldii 2 ‘Elfin drooping spike to 6 cm long, in pale tones of green, tan Leek-orchid’ and P. aff. fitzgeraldii 3 ‘Brown-lip Leek- and lilac, a darker brown median stripe outside each orchid’. The first and third of these also occur in South segment. Floral bract ovate, pale, c. 1.5 × 1 mm, obtuse Australia, the ‘Brown-lip Leek-orchid’ being snonymous to subacute; ovary sub-sessile, partly enclosed, green, with P. sp. Gum Lagoon (P.J.Lang 1633), above. None erect, 4–5 × 2–3 mm, obovoid , swelling to 4 mm diam., of these taxa closely resemble P. laxum. and dehiscing apically at maturity. Sepals 6–7 × 1–1.5 mm; dorsal sepal ovate-lanceolate, much decurved at Key to the P. fitzgeraldii complex in South Australia maturity, pale green inside, pale brown outside; lateral 1. Sepals not or hardly separating, dark coloured, segments sepals free, sub-erect, curved, slightly divergent with a parchment like in texture . 2 sub-gibbous base, green inside brown out, tips entire. 1: Sepals widely separating, of varying colour but not dark, Petals linear, c. 4 × 1 mm, pale green with white edges, segments soft, not parchment like ................. 3 widely spreading. Labellum sigmoid, lanceolate, to c. 5 2. Flowers almost black, smaller than the ovary; sepals not expanding, tips incurved ............... P. goldsackii × 2 mm when flattened; lamina palest pink, the margins 2: Flowers dark maroon and green, as large as or larger than incurved, undulate, ciliate, base horizontal, ovate and the ovary; sepals partly expanding and the tips recurved . slightly humped, recurved gradually about the middle to . P. sp. Enigma (R.J.Bates 2350) give a sigmoid appearance in side view, the tip curved 3. Labellum callus almost glabrous except for vestigial forward, acute with inrolled margin; callus plate smooth pubescence around margins; few-flowered plants . green and channelled before the bend, then raised into . P. occultans 3: Labellum callus variously pubescent; flowers usually a tongue c. 0.6 × 0.4 mm; labellum surface minutely numerous .................................... 4 papillose with sparse lateral pubescence. Column c. 0.5 4. Flowers wholly pale green . P. pallidum × 0.5 mm with a brown caudate anther cap; stigma 0.2 × 4: Flowers with at least some purple or pink tints . 5 0.2 mm with a curved surface, rostellum erect, slender, 5. Flowers less than 5 mm across, of similar size to ovary ... to 0.1 mm high; viscidium tiny; stipe to 0.1 mm long; . P. fecundum column arms bilobed, white, oblong, c. 1 × 0.5 mm, 5: Flowers greater than 5 mm across, larger than ovary ... 6 obtuse, dentate, basal lobe only c. 0.1 mm long; pollinia 6. Whole plant rather lax; flowers more than twice as long as ovoid, to 0.4 mm diam., in bright yellow bundles. Fig. 1. wide, in tints of green, pale brown and pale pink; labellum weakly sigmoid in profile, its apex not erect . Flowering. Late September to October; the short lived . P. laxum flowers emit a strong sweet fragrance. 6: Whole plant rigidly erect; flowers about twice as long as wide, predominantly maroon; labellum not sigmoid in Distribution and ecology. Known presently only from a profile, its apex strictly erect ..................... 7 single hill between Wanilla and Koppio on southern Eyre 7. Labellum brown; lateral sepals widely spreading, thick Peninsula (Port Lincoln district). The Clark property textured and greater than 2 mm broad .