The cryptic Hoya caudata

This Hoya has thin wiry stem and tough leaf that looks like its lichen covered. It is a native of Thailand and Malaysia (east and west) and perhaps Kalimantan as well. The mesophyll of the leaf are arranged so that the tissue are densely cross-linked, so the leaves are actually quite tough and resistant to tearing.
A specimen in the wild - as we climbed up a steep limestone slope, we saw one perfectly camouflaged plant scrambling along the mottled rocks.
The corolla of the flower is hairy and there is a long protruding anther appendages. This plant likes to climb on a pole and may rot if pot bound. It is a slow grower and definetely a good plant for people who does not like to mess around with vigorous vines running amok in the nursery. A related but much smaller species is H. flagelata which has similar but smaller speckled leaves and a very different flower.