I had the pleasure of doing some botanising in the jungles of Peninsula Malaysia recently where I encountered some interesting Begonias. 2 of them are those that you would often expect to see in the jungle here, while the other 2 are rare and restricted in their distribution.
Right up in the northern state of Kedah, there is a small little plant growing on precipitous sandstone slopes that Ruth Kiew called "Shilling Begonia". Its latin name is Begonia sibthorpiodes - attributed to its likeness to the pennywort- Sibthorpia. It had very small leaves (1-2 cm diameter) and was growing on a misty vertical cliff about 15-20 m from me so if it had not been for the relatively large pink flowers, I would have dismissed it completely.
Other than being very small, it is also very rare. It has only been recorded growing on the summit of 2 mountains in Kedah, at the altitude of 700 - 1200m.
Way down at the southernmost state of Johore : 2 hours on tarred road (from Singapore), 1 hour of 4X4 and yet another hour of an ascending jungle track by foot took us to the locality of the only remaining habitat of the beautiful Begonia rajah.
This plant was discovered in 1890s where specimens from Trengganu were brought to UK from which all of the plants in the horticulture trade descended from. Although cultivated plants are readily available, the wild plants were supposedly extinct as no specimens were ever seen again.
In 2002, the plant was rediscovered at a remote location in Johore, about 300 km from its last known locality ! As you can see, not only is this plant very rare (at least in the wild), it is also very pretty, which explains its popularity amongst the hobbyists.
The plants we saw were growing on steep rocks close to the stream or adjacent to or even on cascades and waterfalls.This is not an easy condition to replicate in cultivation, which explains why many growers find them difficult.
Under this optimal conditions, some of the plants became quite large, certainly much larger than those I saw in cultivation ....
Along the muddy paths further away from the stream, we saw plenty of this errect Begonia barbellata, a common plant in undisturbed forests throughout S. Thailand and eastern side of Peninsula Malaysia. This plant is attractive due to its red hairy stem and pink flowers but like many Begonias here, its not easy to grow.
This one is growing with some cup fungus .....