Caladenia exstans explained

Caladenia exstans, commonly known as the pointing spider orchid, is a species of orchid endemic to a small area in the south-west of Western Australia. It has a single, hairy leaf and one or two green, yellow and red flowers with a labellum which does not curl downwards but "points" forward.

Description

Caladenia exstans is a terrestrial, perennial, deciduous, herb with an underground tuber and which has a single erect, hairy leaf, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide. One or two green, yellow and red flowers NaNsigfig=2NaNsigfig=2 long and NaNsigfig=1NaNsigfig=1 wide are borne on a stalk NaNsigfig=1NaNsigfig=1 high. The dorsal sepal is erect, NaNsigfig=1NaNsigfig=1 long and about 3sigfig=1NaNsigfig=1 wide at the base. The lateral sepals are NaNsigfig=1NaNsigfig=1 long, NaNsigfig=2NaNsigfig=2 wide at the base, closely parallel to each other and curve forward and upwards. The sepals have thin, yellowish glandular tips. The petals are NaNsigfig=1NaNsigfig=1 long, about 2sigfig=1NaNsigfig=1 wide at their bases and curve backwards. The labellum is NaNsigfig=1NaNsigfig=1 long, NaNsigfig=2NaNsigfig=2 wide and delicately hinged. It is greenish-yellow with a dark reddish-purple tip which is not curled under but points forward. The edges of the labellum are smooth and there are four or more rows of deep red calli along its centre. Flowering occurs from September to early November.[1] [2] [3]

The cryptic colouration of this orchid and the relatively small flower on a long stem make this orchid difficult to find but it is the only greenish spider orchid with a smooth-edged labellum occurring east of Esperance.[4]

Taxonomy and naming

Caladenia exstans was first described by Stephen Hopper and Andrew Brown in 2001 from a specimen collected near Esperance. The description was published in Nuytsia.[5] The specific epithet (exstans) is a Latin word meaning "projecting" referring to the pointed labellum.

Distribution and habitat

Pointing spider orchid is found between Esperance and Israelite Bay in the Esperance Plains biogeographic region where it grows in swamp yate forest and in shallow soil on and near granite outcrops.

Conservation

Caladenia exstans is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.

Notes and References

  1. Book: Jones. David L.. A complete guide to native orchids of Australia including the island territories. 2006. New Holland. Frenchs Forest, N.S.W.. 1877069124. 96.
  2. Book: Brown. Andrew. Dundas. Pat. Dixon. Kingsley. Hopper. Stephen. Orchids of Western Australia. 2008. University of Western Australia Press. Crawley, Western Australia. 9780980296457. 119.
  3. Book: Hoffman. Noel. Brown. Andrew. Orchids of South-West Australia.. 2011. Noel Hoffman. Gooseberry Hill. 9780646562322. 147. 3rd.
  4. Web site: Archer. William. Caladenia exstans. Esperance Wildflowers.
  5. Web site: Caladenia exstans. APNI. 2 February 2017.