In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||Listed as Vulnerable as Caladenia tessellata|
|Recovery Plan Decision||
Recovery Plan required, included on the Commenced List (1/11/2009).
|Adopted/Made Recovery Plans||
National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata (Duncan, M., 2010b) [Recovery Plan] as Caladenia tessellata.
|Policy Statements and Guidelines||
Draft survey guidelines for Australia's threatened orchids (Department of the Environment, 2013b) [Admin Guideline].
Federal Register of
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Caladenia tessellata.
Documents and Websites
|State Listing Status||
|Scientific name||Caladenia tessellata |
|Reference||Australian Orchids 1(2): 3rd plate (1876).|
Caladenia tesselata 
Arachnorchis tessellata 
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
Scientific Name: Caladenia tessellata
Common Name: Thick-lipped Spider-orchid
Other Names: Daddy Long-legs
Conventionally accepted as Caladenia tessellata (Jones 1991b). Sometimes the genus Caladenia is referred to as Arachnorchis.
Caladenia tessellata was described in 1876 from plants collected at Hunters Hill near Sydney, New South Wales (NSW). There is some uncertainty as to whether the Victorian populations are C. tessellata or an undescribed species, and whether the East Gippsland populations are the same taxon as the South Gippsland populations (Jones 1999 pers. comm.). However, until these taxonomic questions are clarified, all populations will be treated as C. tessellata (Duncan 2010b).
The Thick-lipped Spider-orchid is a perennial orchid that sprouts annually from an underground tuber. It has a single slender flowering stem which bears one or two 3 cm yellow-green flowers (with maroon stripes and suffusions), is hairy and grows to 30 cm in height. The perianth (outer whorl) segments are slender to broadly obovate and up to 2.5 cm long; the dorsal sepal is erect and incurved; the lateral sepals are deflexed and point forward; the petals are often strongly deflexed against the ovary; the labellum is broadly heart-shaped; and the lateral lobes are thickened and obliquely erect and the margins entire (or occasionally with a few short teeth). There is a densely packed cluster of short, thick, clubbed calli that are central and glossy purple to black. These are at the base, and often break into two rows extending into the labellum mid-lobe (Backhouse & Jeanes 1995; Bernhardt 1993; Bishop 2000; Duncan 2010b; Jones 2006).
The Thick-lipped Spider-orchid is endemic to mainland south-east Australia. It is distributed from the central coast of NSW to the Westernport region of southern Victoria. This includes the South East Coastal Plain, South East Corner, and Sydney Basin bioregions (Environment Australia 2000c). The species usually occurs on or near the coast, but in southern NSW it extends well inland to Braidwood (Duncan 2010b).
Within NSW, the orchid is known to occur within the Hawkesbury-Nepean, Hunter-Central Rivers, Southern Rivers and Sydney Metro Catchment Management Regions (Duncan 2010b; NSW DECCW 2005oy).
Historically, the Thick-lipped Spider-orchid was relatively widespread in coastal areas between Newcastle in NSW and Westernport in Victoria. Herbarium records of the species exist from Sydney and suburbs (Como, Loftus, Penshurst, Berowra, Sutherland, Caringbah, Castlecrag), the Royal National Park, Queanbeyan, Heathcote, Huskisson, Ulladulla, Jervis Bay, Wyong in NSW; and Howe Range, Cann River, Sale/Stratford, Mt. Raymond and Port Albert in Victoria. However, plants have not been seen at most of these sites for a number of years, and the species has suffered a substantial decline in overall abundance. Destruction of habitat, largely for urban and industrial development, is the cause of this historic decline (Duncan 2010b).
Generally, the populations of Thick-lipped Spider-orchid that remain are small and highly fragmented. As a result, risk of local extinction is high at many sites (Duncan 2010b).
Population size figures may be an underestimate due to the suppression of flowering in the absence of recent fire (especially in thick or heathy woodland habitat) (Duncan 2010b). However, approximately 20 populations of the species are known. Duncan (2010b) identified 19 populations containing approximately 450 plants, and Smales and Nelson (2008) identified the largest known population, containing approximately 180 plants, near Orbost, Victoria.
The following is a table identifying 19 of the known populations of Thick-lipped Spider-orchid; with estimates of population size and extents and details of the population’s land management and tenure (Duncan 2010b).
|Location||Population size (plants)||Extent (ha)||Land management and tenure||Comments|
|New South Wales|
|Morton National Park (NP)||~60||< 10||DECCW|
|Munmorah State Recreation Area||~20||< 10||DECCW||Plants reported as 'scattered; not seen since 1999'|
|Braidwood (private property)||~10||< 1||Private|
|South Pacific Heathland Reserve||~10||< 1||DoL||Plants not seen since 2001|
|Wyrrabalong NP||< 10||< 2||DECCW||Plants not seen since 1997|
|Porter Creek Wetland Reserve||< 10||< 2||WSC||Plants not seen since 1999|
|Wilsons Promontory NP||~100||about 50||PV||At least 3 sub-populations; however, plants not seen at 2 sites since 2000|
|Wonthaggi Heathlands Nature Conservation Reserve (NCR)||~40||about 25||PV|
|Colquhoun State Forest (SF)||< 40||about 25||DSE||Plants in 5 small, scattered groups|
|Won Wron SF||~30||about 20||DSE||Plants in 3 small, scattered groups|
|Gurdies NCR||~30||about 20||PV||Plants occur in 3 separate groups|
|Ewing Morass Wildlife Reserve||< 20||< 10||PV|
|Croajingalong NP||~10||about 50||PV|
|Moormurng Flora and Fauna Reserve||< 10||< 1||PV|
|Nooramunga Multipurpose Coastal Park||< 10||< 1||PV|
|Yarram||< 10||< 5|
|Tarwin Lower||1||< 1|
Abbreviations: DECCW = Department of Environment, Climate Change and Water (NSW); DoL = Department of Lands (NSW); DSE = Department of Sustainability and Environment (Victoria); PV = Parks Victoria.
The absence of plants detected at previously known sites is considered an indication of future declines in Thick-lipped Spider-orchid numbers. In NSW, for example, at least two populations have become extinct since the 1980s, and at least 14 in Sydney and the South Coast populations have not been recorded since the mid 20th Century. It is thought that the species will become extinct in the wild in NSW unless conservation management is undertaken (Duncan 2010b; NSW Scientific Committee 2002k).
Twelve of the 20 known populations occur within the reserve system (Duncan 2010b).
The Thick-lipped Spider-orchid is known to favour low, dry sclerophyll woodland (for example open Kunzea woodland) with a heathy or sometimes grassy understorey on clay loams or sandy soils (Bernhardt 1993; Bishop 2000; Cross 1995; Fitzgerald 1876). More specifically, the population at Braidwood occurs in dry, low Brittle Gum (Eucalyptus mannifera), Inland Scribbly Gum (E. rossii) and Allocasuarina spp. woodland with a sparse understorey and stony soil. In Victoria, the orchid grows in heathland, heathy or grassy woodland, and grassy or sedgy open forests in well drained sand and clay loams (Duncan 2010b).
The Thick-lipped Spider-orchid flowers from late September to early November and flowers remain open for a few days to a few weeks, depending on pollination and climatic conditions. Fruits usually take 5–8 weeks to mature following pollination, and plants reproduce solely from seed.
The Thick-lipped Spider-orchid grows in a complex relationship with a mycorrhizal fungus, necessary for seed germination and providing some nutrients to the orchid. Pollination is probably via sexual deception through the process of pseudocopulation (Peakall & Beattie 1996), with pollination by an undescribed black wasp of the genus Phymatothyninus observed at one site in NSW (GEC 2003 cited in Duncan 2010b). The species’ summer dormancy is broken in response to soaking rains in autumn, with leaf emergence occurring in late autumn or early winter (Duncan 2010b).
The species’ response to fire is not well understood. While plants in several populations flower regularly in the absence of fire, for others, especially those growing in dense heath, flowering is much more sporadic and probably relies on periodic fire to remove surrounding vegetation and stimulate flowering. Longevity of the orchid is not known (Duncan 2010b).
Arachnorchis x variabilis (formerly known as Caladenia variabilis) is an apparent natural hybrid between the Eastern Spider-orchid (C. orientalis) and Thick-lipped Spider-orchids from south-east Victoria (Jeanes & Backhouse cited in Jeanes 2002).
The Thick-lipped Spider-orchid is most similar to the Heart-lipped Spider-orchid (Caladenia cardiochila). However, the former can be distinguished by its usually smaller, duller flowers, often with more strongly deflexed perianth segments. Furthermore, Thick-lipped Spider-orchid labellum generally have a broader, more open cluster of calli that sometimes breaks up towards the apex, with two rows extending onto the midlobe (Backhouse & Jeanes 1995; Bernhardt 1993; Bishop 2000; Duncan 2010b; Jones 2006)
The Thick-lipped Spider-orchid is also similar to the Clubbed Spider-orchid (C. clavigera) (Fitzgerald 1876). The differences between the two orchids are listed below:
|Clubbed Spider-orchid (Caladenia clavigera)||Thick-lipped Spider-orchid (Caladenia tessellata)|
|Flowers 7.6 cm in diameter||Flowers 3.8–5.1 cm in diameter|
|Sepals contracted for 1/3 their length and clavate at ends||Sepals not contracted, not clavate|
|Column slightly curved||Column very sharply curved|
|Anther markedly mucronate||Anther slightly mucronate|
|Wings of column moderately dilated||Wings considerably dilated near anther|
|Labellum recurved||Labellum flatter, not recurved|
|Half of labellum towards the point naked, with the exception of faint raised lines corresponding to the spaces between the rows of calli||Same portion of labellum covered with close set calli, in 4 rows|
|Half of labellum to its base traversed by 4 rows of slender distinct bent calli||Same portion of labellum, for half length, bearing 4 rows of thick, close-set, bent calli, and at the base a group of upright clavate calli|
|Glands at the base of the column globular||Glands at the base of the column oval|
|Leaf broad||Leaf narrow|
|Whole plant smaller and slighter|
Habitat Disturbance or Destruction
The main threat to the species, at most sites, is disturbance to or destruction of plants and habitat. Most plants occur close to tracksides and are at risk from walkers and track maintenance/fire protection activities. Accidental trampling and site disturbance are problems at the Wilsons Promontory, Colquhoun, Moormurng and Won Wron sites and is a serious problem at the Gurdies NCR site. Rubbish dumping is a potential threat at the Colquhoun SF site and Wonthaggi Heathlands NCR, which is utilised for recreational activities and therefore is also at risk of accidental trampling by humans, Dogs (Canis lupus), bicycles etc. Trampling by feral deer (Family Cervidae) is also a risk for populations in South Gippsland. There is a potential for road/track maintenance activities and fire protection works to damage trackside plants at the Moormurng, Tarwin Lower, Wonthaggi Heathlands and Wilsons Promontory sites. The population at the South Pacific Heathland Reserve at Ulladulla (NSW) may have been destroyed by roadworks. Accidental site disturbance caused by road maintenance activities is a threat at the Genoa site as some plants occur quite close to a gravel road. Disturbance caused by feral Pigs (Sus scrofa) is a potential problem at the Braidwood (private property) site (Duncan 2010b).
Altered Fire Regimes
It is highly likely that some populations of the Thick-lipped Spider-orchid, especially those growing in heath or heathy woodland, require periodic summer fires to reduce surrounding vegetation and stimulate flowering and seedling establishment. As a result, prolonged absence of fire or other biomass reduction processes may be detrimental to flowering. The timing of fire is also important, with the best time for orchids being late summer or early autumn; after seed dispersal but prior to new shoot growth (Duncan 2010b).
Grazing and Predation
Grazing by macropods threatens, or has the potential to threaten, almost all populations. In addition, grazing by introduced herbivores and consumption of orchid tubers by bandicoots threatens the species. The Rabbit (Oryctolagus cuniculus) threatens the species at the Braidwood and Moormurng sites; Hog Deer (Axis porcinus) at the Wilsons Promontory NP site; Fallow Deer (Dama dama) and Sambar Deer (Cervus unicolour) at the Moormurng site and tuber consumption by bandicoots has been observed at Munmorah, Wyrrabalong and Porter Creek Wetland sites (Duncan 2010b).
Weed invasion is a lesser threat to the species. However, Cluster Pine (Pinus pinaster) has invaded the Wonthaggi Heathlands site, and Bridal Creeper (Asparagus asparagoides) is established at the Moormurng site. Horses and vehicles have the potential to introduce weeds at the Moormurng Flora and Fauna Reserve (FFR) and Wonthaggi Heathlands NCR sites (Duncan 2010b).
The species is at risk from catastrophic events due to the small number of extant populations and the low numbers of plants (NSW DECC 2005oy).
Recovery actions identified in the National Recovery Plan for the Thick-lipped Spider-orchid Caladenia tessellata (Duncan 2010b) are structured to acquire baseline data, assess habitat condition, including ecological and biological function, and maintain or improve population growth through protection and management. On-ground site management aims to mitigate threatening processes and thereby ensure against extinction. A range of strategies will be necessary including: weed control, caging/fencing, control of pest animals, and fire management. In addition, seed bank dynamics, recruitment and environmental effects on seed production require investigation and a census should be undertaken. Cultivation of an ex-situ population is an option for reintroduction.
The specific recovery plan actions are as follows (Duncan 2010b):
- Determine distribution, abundance and population structure.
- Determine habitat requirements.
- Ensure that all populations and their habitat are protected and managed appropriately.
- Manage threats to populations.
- Identify key biological functions.
- Determine the growth rates and viability of populations.
- Establish a population in cultivation.
- Build community support for conservation.
NSW Priority Recovery Actions
Priority actions are the specific, practical activities that must be undertaken to recover a threatened species, population or ecological community. The NSW office of Environment and Heritage has identified ten priority actions to help recover the Thick-lipped Spider-orchid in NSW. These actions are as follows (NSW DECCW 2005oy):
- Undertake regular surveillance to detect any decline in populations and to detect threats.
- Collect seed and soil for NSW Seedbank. Develop collection program (including mycorrhizal symbiont) in collaboration with Botanic Gardens Trust (BGT) - single provenance.
- Establish live ex-situ collection in collaboration with BGT - single provenance. Locate sites for reintroduction to the wild.
- Investigate seed viability, germination, dormancy and longevity (in natural environment and in storage).
- Develop and distribute Environment Impact Assessment guidelines.
- Ensure long term protection of crown land habitat in the Ulladulla area.
- Negotiate long-term protection for Braidwood site.
- Acquire baseline population data for key populations in Palerang and Wyong Local Government Areas and monitor every 1–3 years.
- Conduct surveys in bushland reserves in the Ulladulla area.
- Conduct surveys in likely suitable habitat.
Major studies of the Thick-lipped Spider-orchid include:
- Caladenia Sect. Calonema survey and ex situ conservation (Cross 1995)
- Some new combinations and a new hybrid genus in Orchidaceae: Diurideae, for eastern Australia (Jeanes 2002)
- A new classification of Caladenia R.Br. (Orchidaceae) (Jones et al. 2001).
Management documents for the Thick-lipped Spider-orchid include:
- National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata (Duncan 2010b)
- Tessellated Spider Orchid Caladenia tessellata - profile (NSW DECCW 2005oy)
- Caladenia tessellata (a terrestrial orchid) - endangered species listing (NSW Scientific Committee 2002k).
The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.
|Threat Class||Threatening Species||References|
|Human Intrusions and Disturbance:Recreational Activities:Soil disturbance and/or trampling due to bushwalking||National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata (Duncan, M., 2010b) [Recovery Plan].|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Oryctolagus cuniculus (Rabbit, European Rabbit)||National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata (Duncan, M., 2010b) [Recovery Plan].|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Pinus pinaster (Maritime Pine, Cluster Pine)||National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata (Duncan, M., 2010b) [Recovery Plan].|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Asparagus asparagoides (Bridal Creeper, Bridal Veil Creeper, Smilax, Florist's Smilax, Smilax Asparagus)|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Grazing, tramping, competition and/or habitat degradation||Sus scrofa (Pig)|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Grazing, tramping, competition and/or habitat degradation||Cervus unicolor (Sambar)|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Grazing, tramping, competition and/or habitat degradation||Axis porcinus (Hog Deer)|
|Dama dama (Fallow Deer)|
|Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity)|
|Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes|
|Pollution:Garbage and Solid Waste:Dumping of household and industrial waste|
|Transportation and Service Corridors:Roads and Railroads:Development and/or maintenance of roads|
|Uncategorised:Uncategorised:threats not specified||Caladenia tessellata in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006dm) [Internet].|
Backhouse, G.N. & J.A. Jeanes (1995). The Orchids of Victoria. Carlton: Miegunyah Press, Melbourne University Press.
Bernhardt, P. and R. R. Rowe (1993). Prasophyllum. In: Harden G.J, ed. Flora of New South Wales. 4:155-163. Kensington: New South Wales University Press.
Bishop, A. (2000). Field Guide to the Orchids of New South Wales and Victoria. Sydney, NSW: University of New South Wales Press.
Cross, R. (1995). Caladenia Sect. Calonema survey and ex situ conservation. Canberra, Australian Nature Conservation Agency.
Duncan, M. (2010b). National Recovery Plan for the Thick-lip Spider-orchid Caladenia tessellata. [Online]. Melbourne, Victoria: DSE. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/caladenia-tessellata.html.
Environment Australia (2000c). Revision of the Interim Biogeographic Regionalisation for Australia (IBRA) and development of version 5.1. [Online]. Available from: http://www.environment.gov.au/parks/nrs/ibra/version5-1/summary-report/index.html.
Fitzgerald, R.D. (1876). Australian Orchids.
Jeanes, J.A. (2002). Some new combinations and a new hybrid genus in Orchidaceae: Diurideae, for eastern Australia. Duretto, M. & T. Lebel, eds. Muelleria. 16:81-82. Melbourne: Royal Botanic Gardens.
Jones, D.L. (1991b). New Taxa of Australian Orchidaceae. Australian Orchid Research. 2. Essendon: Australian Orchid Foundation.
Jones, D.L. (1999). Personal Communication.
Jones, D.L. (2006). A complete guide to Native Orchids of Australia, including the island Territories. Sydney, NSW: New Holland Publishers (Australia) Pty Ltd.
Jones, D.L., M.A. Clements, I.K. Sharma & A.M. McKenzie (2001). A new classification of Caladenia R.Br. (Orchidaceae). The Orchadian. 13(9):389-417.
NSW Department of Environment, Climate Change and Water (NSW DECCW) (2005oy). Tessellated Spider Orchid Caladenia tessellata - profile. [Online]. Available from: http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=10124.
NSW Scientific Committee (2002k). Caladenia tessellata (a terrestrial orchid) - endangered species listing. [Online]. Available from: http://www.environment.nsw.gov.au/determinations/CaladeniaTessellataEndSpListing.htm.
Peakall, R. & A.J. Beattie (1996). Ecological and genetic consequences of pollination by sexual deception in the orchid Caladenia tentaculata. Evolution. 50:2207-2220.
Smales, I. & K. Nelson (2008). Flora, terrestrial fauna and net gain assessment of two road alignments from the Patricia Baleen Gas Plant to the Princes Highway, Orbost, Victoria- Report to Santos Ltd. Melbourne: Biosis Research.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2014). Caladenia tessellata in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sat, 30 Aug 2014 17:00:10 +1000.