Species Profile and Threats Database

For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
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 Endangered as Caladenia richardsiorum
Recovery Plan Decision Recovery Plan required, included on the Commenced List (1/11/2009).
Adopted/Made Recovery Plans Recovery Plan for three orchid species in South Australia and Victoria: Caladenia richardsiorum (Little Dip Spider-orchid), Caladenia calcicola (Limestone Spider-orchid) and Pterostylis tenuissima (Swamp Greenhood) (Dickson C.R., R.A. Anderson, A. Murphy, A. Pritchard & A. Craig, 2012) [Recovery Plan] as Caladenia richardsiorum.
Policy Statements and Guidelines Draft survey guidelines for Australia's threatened orchids (Department of the Environment, 2013b) [Admin Guideline].
Federal Register of
    Legislative Instruments
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 richardsiorum.
State Listing Status
SA: Listed as Endangered (National Parks and Wildlife Act 1972 (South Australia): June 2011 list) as Caladenia richardsiorum
Scientific name Caladenia richardsiorum [55018]
Family Orchidaceae:Orchidales:Liliopsida:Magnoliophyta:Plantae
Species author D.L.Jones
Infraspecies author  
Reference Australian Orchid Research 2: 31 (1991).
Other names Arachnorchis richardsiorum [76228]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Caladenia richardsiorum

Common name: Little Dip Spider-orchid

Other common names: Nora Creina Spider Orchid

Conventionally accepted as Caladenia richardsiorum (CHAH 2005). Previously referred to as Arachnorchis richardsiorum, Caladenia sp. A, Calonema richardsiorum and Calonemorchis richardsiorum. Sometimes genus Caladenia is referred to as Arachnorchis.

The Little Dip Spider-orchid is a hairy terrestrial herb, with a slender, shortly hairy flowering stem growing to 40 cm in height (Bates 2011; Jones 1991b). The leaf is linear-lanceolate, pale green and velvety and is large, growing to 20 cm in length. The flower is usually single, with segments all similar, lanceolate and rigid and growing up to 4 cm in length. Sepals are yellowish-green with dark, clubbed osmophores. The labellum (lip) grows to 1.5 cm in length, is ovate, hardly lobed, broadest at the midpoint, an apex that curls under, margins have chocolate brown, linear, short teeth that are regularly spaced and the species has short, brown lamina calli in four to six spaced rows. The dorsal sepal is erect and slightly curved over the column. The lateral sepals spread obliquely, are broad at the base and suddenly constrict into narrow points at the approximate middle, and petals are smaller and upswept behind the flower (Bates 2011).

The Little Dip Spider-orchid is endemic to south-eastern South Australia. The orchid is highly localised and poorly conserved in coastal sands between Canunda Conservation Park and Kingston, and is often near salt-lakes. The species also has an outlying population near Meningie (Bates 2011; Jones 1991b; Jones 2001 pers. comm.; SA DEH 2007c).

The Little Dip Spider-orchid grows in a range of habitats from exposed limestone cliffs to sheltered coastal mallee vegetation, in closed forests and low coastal scrub on grey calcareous sands, often found in leaf litter (Jones 1991b; Jones 2001 pers. comm.) and on the inland side of coastal dunes (Bates 2000 pers. comm.).

Flora associated with the Little Dip Spider-orchid include Coastal Daisy-bush (Olearia axillaris), Coast Beardheath (Leucopogon parviflorus), Coastal Mallee (Eucalyptus diversifolia), Dryland Tea-tree (Melaleuca lanceolata), Drooping Sheoak (Allocasuarina verticillata), Muntries (Kunzea pomifera), Bower Spinach (Tetragonia implexicoma), Swainson's Pea (Swainsona lessertifolia) and Coast Velvet-bush (Lasiopetalum discolor) (SA DEH 2007c).

The Little Dip Spider-orchid produces a single leaf, growing up to 16–22 cm long, in winter (SA DEH 2007c). The species then flowers between late September and early November (Jones 1991b). After flowering, all vegetative parts of the Little Dip Spider-orchid die off and the plant reverts to dormancy as an underground tuber, where it remains for approximately six months (SA DEH 2007c).

This Little Dip Spider-orchid has affinities with Melblom's Spider-orchid (Caladenia hastata) but can be immediately distinguished by its much larger leaf and its greenish-yellow flowers with much broader sepals and petals, shorter sepalline osmophores on the petals. Melblom's Spider-orchid, by comparison, has white to creamy coloured flowers with very dark clubs (Bates 2011; Jones 1991b).

The Little Dip Spider-orchid is most closely related to the Robust Spider-orchid (Caladenia valida), but is distinguishable by its consistently dark brown clubs, calli and fringing (Bates 2011).

Threats to the Little Dip Spider-orchid include herbivory by the Rabbit (Oryctolagus cuniculus), Hares (from the genus Lepus), kangaroos (Macropodidae sp.) and domestic stock; competition from weeds including Bridal Creeper (Asparagus asparagoides), Blue Periwinkle (Vinca major) and Myrtle-leaf Milkwort (Polygala myrtifolia); and habitat destruction and fragmentation from road maintenance, urban development and recreational activities (SA DEH 2007c).

Beachport District Development Association (BDDA) (SA) received $1400 of funding through the Threatened Species Network Community Grants in 2001–02. This grant was intended to be used for training of volunteers for weeding activities at two locations containing this species and for monitoring of orchid populations.

A Recovery Plan for the Little Dip Spider-orchid is currently in preparation. Recovery actions outlined in the document will include the following (SA DEH 2007c):

• Population monitoring.

• Identifying potential habitat.

• Ensuring that all populations and their habitat are protected.

• Managing threats to populations: for example, weed's, herbivory and disturbance.

• Collection and storage of seed and mycorrhizal fungi.

• Supporting the community and landholders to effectively manage Little Dip Spider-orchid habitat.

• Research on the ecology and management of Little Dip Spider-orchid.

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
Uncategorised:Uncategorised:threats not specified Caladenia richardsiorum in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006di) [Internet].

Bates, R.J (2011). South Australia's Native Orchids. Compact disc. Native Orchid Society of South Australia.

Bates, R.J. (2000). Personal Communication.

Council of Heads of Australasian Herbaria (CHAH) (2005). Australian Plant Census. [Online]. Australian National Herbarium, Australian National Botanic Gardens and Australian Biological Resources Study . Available from:

Jones, D.L. (1991b). New Taxa of Australian Orchidaceae. Australian Orchid Research. 2. Essendon: Australian Orchid Foundation.

Jones, D.L. (2001). Personal Communication.

South Australian Department of Environment and Heritage (SA DEH) (2007c). Threatened Flora of the South East- Little Dip Spider-orchid Caladenia richardsiorum. [Online]. South Australia: South East Natural Resources Management Board, DEH. Available from:

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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 richardsiorum in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: Accessed Tue, 23 Sep 2014 10:25:56 +1000.