Henekelia platypus and a crinkly relative

I have sighted Henckelia platypus numerous times in primary forests of Malaysia and Thailand and it seemed to prefer slopes near the water. This is one of the habitat of the plant, perched on a rocky bank beside the stream. It is supposedly still found in Singapore BTH but it must be very rare now.

It has a trunk up to waist high with a rosette of textured leaves, which in itself would be quite attractive. When in full flowering glory however, the plant is magnificent. The flowers may be white or mauve with yellow stripes at the throat.

There is also smaller relative of this plant growing in my plot which has similar flowers but extremely crinkly leaves. It is very neat - but I have yet to find a name for it since these plants are so little known and literature is scarce.

Cultivation of these interesting gesneriads are not widespread however, as they like hot humid environment which are not easily replicated at home. On top of that, their sensitive foliage is very sensitive to stagnant water and chemicals.

A Gesnid limestone specialist

A rather interesting Paraboea from the steep limestone karst of Southern Thailand.

The rosette of hirsute leaves is vegetatively similar to the one I had previously posted except that the flowers are larger and the cymes are less branched.

Paraboeas are specialised limestone plants that are fully adapted to the free draining substrate and bright light. Some of them can be tree-like but generally they are small to mid size plants. They are closely related to Boea, both having hairy leaves but differing in the hairs being simple for Boea and cobweb-like in Paraboea. As a general guide, those that has white or silvery reflective leaves grow in the most exposed places while those with green leaves require some shade. As you can see from the next 2 photos, they have resurrection abilities - tolerating extreme drought by rolling up the leaves and shrivelling and reviving once water becomes available again.

A sample of terrestrial Borneo Gesneriads

A mix bag of the ground herbs from the African Violet Family encountered during a couple of trips in Sarawak..... posting here in the hope of getting them identified.

This smallish herb with Henckelia-like habit appeared to be from genus Hexatheca, maybe H. fulva. It was found on shady ledges at the bottom of a limestone hill in West Sarawak.

Found on the same limestone hill as the previous species but on highly exposed high grounds subjected to dry winds and direct sun is this Paraboea with silvery felty leaves. It reminds me of Sinningia leucotricha commonly found in gesneriad collections and utilised the same strategy to reflect sun rays and heat from the leaf surface.

Borneo is very rich in Cyrtandra species and this is one of them - but exactly what species I do not know. The leaves are glabrous and quite succulent. It is also confined to limestone.

This last species is probably most horticulturally interesting, with its shiny variegated leaves - and tidy size (less than one foot tall). I had initially thought it was some kind of Scorpion's tail (genus Pentaphragma) but closer inspection showed Cyrtandra-like bloom between the leaves. Unfortunately the habitat which I had found it had been destroyed and had not seen it anywhere else. Unlike the other species, it inhabits sandstone embarkments by the side of the forest.

If readers can ID any of the plants please share it here.

Cheers.

Spelaeanthus chinii

This is the only species in the genus - found on limestone slopes in peninsula Malaysia. It appears to have a rather limited distribution and hence vulnerble to any habitat disturbances. It has filmsy hairy leaves and has white widely opening flowers borned on a branched panicle.
I found this plant perched on a damp dark limestone wall in Pahang. This appears to be too dark for most competing plants.

Not far from it is a carpet of the curious giant one-leaf Gesneriad, Monophyllea horsfieldii.

An Epithemia

An ephemeral Epithemia that would set seed and die off suddenly - this one has been growing wild at my plot for years now - originally probably coming from seed heads from a limestone hill in Pahang.

Stripey lipsticks from Borneo

I obtained this unique lipstick vine from Borneo a few years ago - a cutting from a friend. The short flower with stripped corolla coupled with the shallow dish shaped fused sepals is quite eye catching. It is reported to be common on palm plantations in Sarawak but I have only seen it once growing at a depleted forest. I did witness an impressive display of mass flowering at a private garden, where a dense carpet of this vine cover a trellis over a 3 metre square area sprouting multitudes of red dots along their lengths. There are 2 forms shown here, one with pink and the other with red sepal. Despite its uniqueness, I could only pin it down to be Aeschynanthus tricolor recently The reason is that there is another similar species from Borneo - Aeschynanthus hians. I found Anthony Lamb's article in GardenWise showing rather blurred photographs of both species but all it said was that the difference was in the calyx. I only understood what he meant when I eventually found this curious stripped flowered Aeschynanthus with larger flaring calyx. This would be the A. hians, which is a rarer species confined to northern Sarawak. From these pictures one can see the difference lie in the larger, widely serrated calyx - the flower is similarly stripped.

Giant gesneriads

For most gardeners, giant tree-like plant is not something associated with members of Gesneriad family. Out of the three thousand plus species in this large family, there are actually a quite a few giants that are very little known compared to their smaller cousins.

While scrambling up an open slope on a steep limestone hill in Sarawak, I came across this giant Paraboea - its a man's height even before blooming, its multiple branched inflorescence adding a further metre or so.



I reckon this is either a P. havilandii or the related P. treubii - both of which, according to literature, can be up to 2m high. The spiralling seed pod is characteristic of this genus - the pod builds up internal pressure and eventually implodes with a twisting action that catapult the seeds from mother plant. Note also the retention of dried leaves at the base, the function of which is a mystery.

There are many more examples of giant Gesneriads - like the Brazilian Paliavana , which I found from the excellent web site by Mauro. While visiting one of Europe's botanical gardens, I unexpectedly stumbled upon this striking Jamaican native, - Rhytidophyllum tomentosum, which I know nothing of except that its likely pollinated by bats.
The felty leaves remind me very much of the Henckelia back home but the stiff flowers are quite unique.


I do not think any of these large and drab plants will be popular to gardeners soon unless hybridisers manage to perform some miraculous makeovers. Still, they are interesting botanical curios for me ....

Unknown Gesneriad

Found this stunning Gesneriad growing on a sandstone mountain slope in southern Sarawak.



I have absolutely no idea what it is - if I have to make a guess it would be a Henckelia.... suggestions much welcome.

Unusual resurrection plant

This interesting Gesneriad was found growing on bare limestone hills of S Thailand. You can see that in nature, the dead leaves are left wrapped at the base of the plant.
On several occasions when I failed to water the plant, the leaves withered totally to the brown colour of the dried leaves seen above. Upon dunking it in water several times, the plant miraculously revived - with the same brown leaves turning green once more.

The plant produced multiple branching inflorescence once or twice a year
the bloom appeared to be typically Paraboea but it has yet to set seed naturally so far, which would verify its standing.
The leaves are hirsute on both sides, with brown hairs at the leaf edges, venations and petioles.

I am guessing its some kind of Paraboea but its specific name remain to be identified. Any suggestions are much welcome.

Henckelia malayana

This is a fairly commmon relative of African violets and appears to be confined to hills and highlands in Peninsula Malaysia. Like so many local members of this family, it is not well known nor commonly grown although it does has merits - its felty leaves for example, and its yellow flowers which is relatively unusual amongsts local gesneriads.

The genus Henckelia was revived by prominent Asian Gesneriad researchers Anton Weber and B. L. Burt in 1998 to include the bulk of the species formerly grouped under Didymocarpus. One would usually encounter members of this large genus, comprising of about 200 species, during a casual walk in a primary lowland forest around the Malesian region. According to Weber and Burt, Didymocarpus now comprises mostly temperate or highland species which may be periodically dormant - not a common trait for lowland tropical gesneriads here.

The trick for growing this plant successfully is cool climate and high humidity, which is not easy to duplicate at home unless you have a bright bathroom with air-con. I collected some seed pods for trial in the lowland and although germination rate is pretty ok, survival has been dismal.

This population is found growing about 50 metres from a mountain stream under very little shade.

Here's another example from the genus Henckelia

The gloriously yellow Aeschynanthus flavidus

A striking lipstick vine that I initially thought was a very fine hybrid, but had my doubts when I verified the origin of the plant. A possible ID was suggested by experts from an institution - a plant first described by Mary Mendum in 1997. Besides the shocking colour, it also has a very tall and flaring calyx.

I wanted to get the publication to confirm the ID but there were always more pressing issues. Eventually, I obtained a copy from an acquaintance. I cannot verify the presence of glanduular hairs inside the flower but the other characteristics matched very well with this plant - the leaf shape, flower colour right down to the "crimson central line and the broken dots and dashes either side" of the lower corolla lobe. According to Mary's paper, when her specimen first flowered, the calyx was short (1.5-2 cm) but subsequent flowers had longer calyx of 2.7-3.4cm, as my series of photos also showed. The shrub also appeared to be rather rare, being found in only 3 localities in North Sarawak.

Just for the record, I had attached the published line drawing from Mary's paper for comparison. What the paper failed to emphasise is the very unique leaf colour -velvety purple-green hairy at the top and brighter green at the edge and pink at the bottom, very pretty even when not in bloom.

This is a treasured gift from my gesneriad friend from Borneo.

Addenda (28 May 2010)
Scroll down this emag for an interesting article by Dr Anthony Lamb
Lipstick flowers of Sabah and Sarawak