26 September 2013

Thelymitra petrophila - Granite Sun Orchid

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Thelymitra petrophila - Granite Sun Orchid

This attractive species is quite common in soil pockets on and around granite outcrops, favouring the heavier reddish brown loams that frequent these environments. Locally, it can also be found in a similar soil over limestone where light seepage gravitates through it to a lower-lying granite environment.

Although this orchid enjoys moist soils, it seems to dislike humid conditions, preferring the drier inland by staying well away from the southwest of the State or coastal regions either side of Perth. The extensive area where it does occur is from Kalbarri to the Nullarbor, plus the southeastern coastal area extending inland to the northwest of Kalgoorlie.

Most plants mature at 30 cm (12”) in height, although some can reach twice that size when they grow through low vegetation. They seldom develop in exposed locations, but probably due to browsing animals like kangaroos, tend to frequent open shrubby copses.

There are up to ten flowers to 2 cm (3/4”) diameter, which open readily on warm sunny days between August and November. Their colour varies to include pink, purple and blue, with the latter being the norm around Esperance.