Seeds of South Australia
Caladenia dilatata (Orchidaceae)
Late Spider-orchid
List of species for Caladenia
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Seed collecting:
December to February
Herbarium region:
South Eastern
NRM region:
South East
IBRA regions
Mount Gambier (SVP02)Southern Volcanic Plain
 Vulnerable   (IUCN: VU B2ab(i,ii,iii))   (Probable Decline)   [change in forestry man'ment a threat]
Bridgewater (NCP01)Naracoorte Coastal Plain
 Near Threatened   (Probable Decline)   [weeds a threat]
Glenelg Plain (NCP02) 
 Vulnerable   (IUCN: VU B2ab(i,ii,iii))   (Probable Decline)   [change in forestry man'ment a threat]
Lucindale (NCP03) 
 Vulnerable   (IUCN: VU B2ab(i,ii,iii))   (Probable Decline)   [nthn records prob wrong ID]
RSCA map:
Regional Species Conservation Assessments per IBRA subregion. Please click the thumbnail map.
AVH map:
Australian distribution map (external link)
SA Census:
Census of South Australian plants (external link)     [genus Caladenia]
Name derivation:
Caladenia from the Greek 'callos' meaning beauty and 'aden' meaning a gland, referring to the colourful labellum and the glistening glands at the base of the column that adorn many of the species. Dilatata from the Latin 'dilatare' meaning widen, dilated or expanded, referring to the spreading segments of the sepals which have expanded glandular tips.
Distribution:
Found in the South-east in South Australia, growing in heathlands and coastal scrublands, often in areas of high rainfall or in dry exposed environments in a variety of soil types. Also found in Victoria and Tasmania.
Status:
Native. Very rare in South Australia. Common in the other States.
Plant description:
Annual terrestrial orchid growing from an underground tuber to 40 cm tall, with a single flower (rarely two). It has a single basal leaf to 6 cm long, oblong to elliptical or lanceolate and hairy. The flower is 20-80 mm mostly green with variable crimson median stripes on the sepals, the labellum is white with green lateral lobes, a maroon tip and calli. This is part of a complex of similar species but can be distinguished by its late flowering time, moderately large flowers and flattened clubs on both the petals and sepals. Flowering between October and November.
Fruit type:
Brown papery ellipsoid capsule.
Seed type:
Very small brown ellipsoid seed with a long cylindrical translucent brown mesh-like covering.
Seed collecting:
Collect fat capsules as they start to dry and turn brown. Pods will split and release the seeds quickly and will require monitoring. To increase the chances of collecting mature pods, it is recommended that a small breathable bag (ie. Organza bags) be used to enclose the developing capsules.
Seed cleaning:
Place the capsules in a container that will hold fine seeds and leave to dry for a few weeks or until the capsule split. Then carefully hold the capsule and tap it gently to release the seeds. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place, refrigerator or in liquid nitrogen.
Seed viability:
For the NVC South East Orchid Project two populations consisting of more than 200 individuals in total were recorded from the Geegeela and Big Heath Conservation Parks. Approximately 328,000 seeds (0.22 g) were banked from these populations. Seed viability ranged from 60% to 75%.
Seed germination:
Seed germination in Caladenia species is difficult without compatible mycorrhizal fungi.