A UNIQUE ROCK ORCHID          by Sue Meech
 
Dockrillia striolata subsp. chrysantha
    Photo: Christine Howells
Dockrillia striolata subsp. striolata 
& subsp. chrysantha
Dockrillia is a recently described genus that was segregated from Dendrobium because of several distinctive characteristics. Mainly tropical, the genus is distributed as far as Fiji and Tahiti but has its greatest development in Australia and New Guinea. Sixteen species occur in Australia, mostly in Queensland and northern NSW. It is represented in Tasmania by one species consisting of two subspecies, Dockrillia striolata subsp. striolata and the newly described Dockrillia striolata subspecies chrysantha. Striolata means faintly striped or grooved, chrysantha means - golden yellow. The genus is named after Alick Dockrill, a contemporary Australian orchidologist. 
Description 
This lithophytic (which means growing on rocks) clumping, rock dwelling orchid grows in spreading
pendulous clumps up to 50cms long, Rhizomes are about 0.2cms thick and are tough and horny. It has short, often curved thick and fleshy terete leaves. Short racemes have 1-3 yellowish upside down flowers 1 .5-2cms across that have dark stripes, which are particularly prominent on the outside of the perianth segments. The labellum is white with greenish deeply crisped margins. It flowers in late September and October. 
Distribution
The subspecies striolata is restricted to the Furneaux group of Islands, from Cape Barren Island and
Flinders Is., in lowland areas up to 400m, it also occurs in NSW and Victoria. Subsp. chrysantha is endemic to mainland Tasmania where it is locally fairly common on the central and northeastern east coast up to 200m. It has brighter butter yellow petals and sepals that lack stripes or are only faintly striped, the flowers also tend to be larger - about 25mm across. 
Habitat
Dockrillia grows on rock faces and boulders, mostly granodiorite and granite, occasionally on dolerite &
sandstone, in open eucalypt forest. Most colonies are found on east-facing sites directly exposed to
moisture laden sea breezes. In these exposed situations the roots penetrate crevices and low areas where litter collects and may grow as scattered individuals or in huge clumps covering boulders or whole cliff faces. 
Propagation 
The species is readily adaptable to cultivation and is especially suited to our temperate climate here in
Tasmania, where they tend to grow more strongly. Dockrillia can be persuaded to grow on rocks or even
on trees in the right garden situation, although I believe snails and slugs are rather partial to them. 
Being a natural in the pendulous department, it could look quite attractive hanging through wire baskets or something similar. The plants are very tolerant of long periods of dryness but a feed of liquid fertilizer during the warm months does them a favour. 
Propagate by dividing the clumps (establish quickly in fresh sphagnum moss) or from seed. Dockrillia roots spread widely over rock surfaces and crevices. As they are not insulated by soil, the plants are very vulnerable to all but low intensity ground fires. Subsp. chrysantha is well represented in reserves, but subsp. striolata is only in the Strzelecki National Park. 
Dockrillia striolata subsp. chrysantha
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