OF THE STIRLING RANGE Nestled between the wetter south-west andthe drier inland region s, and rising some I 000 metres above sea level, the Stirling Range NationalPark provides refuge for an astonishing123 orchid species.This article is based on a chapter from a new book, Mountains of Mystery: A NaturalHistory of the Stirling RangeNational Park, to be publishedby CALMnext year. BYANDREW BROWN he Stirling Range National Park contains about 38 per cent of all known WesternAustralian orchids and includes23 of the27 genera that grow in the south-westofthe State.To find such a large number of orchids in such a relatively small area is remarkableby anystandards, but is not surprisingwhen you considerthe diversetopography of the region. This varies from salt lake marginsand deep,moist valleyfloors to rocky mountain tops.The wide rangeof habitatsscattered throughout thes€ areas include low-lying swamps,seasonal creeks,forests, woodlands, and the dense low shrublandsthat clothe much of the Preoiouspage: left: landscape.These vastly dift-erentareas I lAboae I Risingsome I 000 metresabove sea I King spiderorchid lCaladenia display a magnificent array of orchid I level,the Stirling Rangeprovides a pectinala).An inhabitantof jaryah- species,many of which are now rare refugefor an astonishing123 orchid malli woodlandsthe statelyking spider elsewhere.Many species reach the limits species, is often found standingwell above Photo- Jiri Lochman of their distribution in the park and suYroundingvegetation. Inset: Photo- AndrewBrown severalspecies contain forms that are Dwarf pink fairy lCaladenia reptans found nowhereelse. subsp./eplarJ). A winter flowering lAbooe: Blue china orchid (Cganicula At least five Western Australian species,the dwarfpink fairy forms I attractiveclumps in rocky areasof the I gemmatal- Rarelyflowering unless orchids have been named from park. the bush hasbeen burnt, the blue china collectionsmade in or near the Stirling Photo- GerhardSauerack€r orchid is commonin malleeheathland Range National Park. The narrow areasof the park. Photo- AndrewBrown greenhood (Pterostg lis angusta) and the tall snail orchid (P. dilatatol were both large number of ovulesare fertilisedat described from plants coll€cted by the same time, producing literally botanistAlex Georgewest ofMount Trio thousandsoftiny seedsthatare dispersed and below Bluff Knoll in July, 1969. widelybythe wind. Theadvantage ofthis The first speciesnamed from the strategyis obvious,when it is considered park was found in 1869, when Baron that most other plants requir€ multiple FerdinandvonMueller collected the zebra pollination events to achievea similar orchid (Caladenia caimsianal north of amount of fertilisation. the Stirling Range.The pinkbeak orchid Allorchidsrely on soilfungito infect (Bumettia forrestii) was discoveredjust the germinating seedand providea food a few yearslater by John Forrest, after source on which the young plant can whom it was named, and in 1903 grow. This associationcontinues the rare sandplain sun orchid dwarf hammer (D. micrantha), the throughout the plant'slife andwithout it lThelgmitra psammophila) was also crinkle-leavedbunny (Eriochilus orchids would be unableto survive. foundnearthe Stirling Range.Ironically, dilototus ssp.undulalus) and the swamp Most orchids also have a modified the last two are far more common bunny lE. helonomos). third petal,known asthe labellumor lip, elsewhereand probablywere neververy that looks quite unlike the other two. abundantin the Range. WHATIS AN ORCHID? The labellum of most speciesprovides a More recently, a number of other Orchidshave several unique features landingplatform forvisiting insects,and new orchid specieshave been found in that distinguishthem ftom other plants. in somecases actually resembles a female the park, several of which may be For example, orchids have combined insect. describedfrom collectionsmade there. their pollen-bearingparts (anthers) with Whilesome species found in the park, They are: the big clubbed spider (C. their pollen-receivingparts (stigma),to such as the common snail orchid arrecta), the Jerramungup spider (C. form a single structure known as a (PterostAlisnana), multiply freely by llaccida ssp.pulchra), Heberle'sspider column. producingtwo or more new tuberseach (C. heberleana\,the painted spider (C. Orchids also amassall their pollen year,mostare likethewhitespiderorchid polychromal, the Christmasspider (C. into one or two large bundles, which (Caladmia long icauda subsp.eminens), serotina) , the late spider (C. ultimal , the becomeattached to the bodyofavisiting which rarely replacesits old tuber more commonspider (C, aarians ssp. Dariansl, insect. When these bundles are than once and must thereforerely on the late hamm€r (Drakaeaconfluens), successfullytransferred to the receptive seeddispersal to multiply. the slender hammer (D. gracilisl, the stigmaofanother flower an exceptionally This has led orchids to rely heavily 38 r.r"rsco"r on successfulcross-pollination by insects flower. [n good seasonsyou will be I Cowsfiporchid lCaladeniallaua (thoughin rarecases they self-pollinate). rewardedwith masseddisplays. I subsp.//aua). The brightyellow The resultingrelationship between Theorchids ofthe StirlingRange are I flowersof thecowslip orchid are a commonsight during inseclsand plants makes for a fascinaling remarkably diverse. They range from the spring sruoy, months. the dainty dwarf spider (Caladenn Photo- AndrewRrown The lengths to u,hich orchids go to bfgceana), which grows only srx attractpollinators are as variedas trre centimetreshigh and producesflowers speciesthemselves. Some have flowers Justtu'o centimetresacross, to the tallest that resemblefungi, some smell like of all WesternAustralian orchids. The (Bumettia nigricansl appear only as rotten meat, others havestructures like king leekorchid (Prasophgllum regium) Ieavesin unburnt bushland,but flower pollen the ladenanthers of lilies and growsto wellovertwometres and has up en masse atter fire. The rabbit orchid somesimply mimic other flowers.The to 100 or more flowers. Floral shape (Leptocerasmenziesii) producesdense mastersofdeception are, however, those variesenormously and some specres, mats of leavesin moist areasaiong orchids that fool male waspsor flying suchas the greenhoods (Pterostglisspp.l creeklinesand swamps.These come up ants by imitating the femalesof the and hammer orchids (Drakaea spp.), year after year without ever producing species.A number of the park's orchids havebizarreflowers that hardlyresemble more than one or two flowers.However, 'Wicked havethese attributes. (Seealso flowersat all, if the areais burnt, almostevery plant Deceptions',LANDSCOPE Winter 1991 Some speciesare quite commorr, bursts into bloom. Most leek orchids rssu€.) such as the yellow floweredcowslip lPrasophyllum spp.), bunny orchids orchid (Caladenia/laza), grows (Eriochilus ORCHIDSIN THE PARK which spp.) and beak orchids in most cf the park's habitatsand often \Bumettia spp.)are stimulated by fire. Dueto the Mediterraneanclimate of bloomsin largenumbers. Other specres Two namedhybrids grow in the park. cool,wet winters and hot, dry summers, aremuch rarerorare restrictedto specific The prisoner orchid (Caladenio x thepark's orchids growand Iargely flower habitats.The rare dwarf spider, for erickoniae) isa crossbetween the zebra duringautumn, winterandspring.While example,is known from only one small orchid and th€ paintedspider orchid, a few speciescontinue into summer, areaat the northern end of the park. and the shy spider orchid (C. x most die back to dormant tubers, Other speciesappear only after hot triangularis) is a cross between the resprouting again when autumn rains summer fires have blackenedthe cowslip orchid and the white spider moisten the soil.The besttime to look landscape.It is believedthat ethylene orchid.A carefulobserver may find them for orchids is from August to October, gas produced by the fire promores growingamongst their more common whenup to 90 speciescan be found in fl owering.For instance,red beak orchids parents. t,tNotrnrr:39 of the Stirling WANDOOWOODLANDS SHEOAKTHICKETS which dominate much Range National Park' These areas are to look for The sheoakthickets found along One of the best Places rich in common speciessuch as the red woodlandsat seasonalcreeklines also havetheir own orchids is in the wandoo beak orchid, which appearsyear after park,just south array of orchids. The dragon orchid the northern end ofthe year as large oval-shapedleaves, often Over50 species (Drakonorchb barbarossa) often forms oftheBluff Knoll turnoff. calledelephants'ears. Should its habitat habitat and, as it is large colonies in these areas and is can be found in this be burnt, it will produceup to eight red are reasonably particularly abundant along Papacolla fairly open,the majority and white stripedflowers on eachplant. spot. The best Creek. Its flowers,which appearfrom accessibleand easy to A specieswhich doesnot requirefire is from August to early late September to October, have an time to searchis the magnificent Queen of Sheba i unusuallip thatr€semblesthesize, shape Octoberwhen most are in full bloom. (Thelgmitra uariegala).It is rarer than is instantlY and texture of a flightlessfemale wasp. The zebra orchid many other heathland orchids and l: red-stripedlip fu with the hammerorchids, male wasps ; recognisedby its upswept appearsto be confinedto moist pockets petalsand are initially attrcctedto the plant by an and distinctive stem-clasping in sandyor rocky soils. Like other sun the coloudul