Saturday, March 12, 2011

Hoya campanulata lookalikes part1

Warning: This may be a bit dry for some people .....

There are 2 groups of Hoyas from SE Asia with white, waxy, bell-shaped flowers which has caused confusion amongst growers and taxonomists alike due to their apparent similarities and vendors applying errorneous tags without due diligence. The first is the Hoya campanulata group which appeared widespread in SE Asia and the second are from the wallichii complex which was collected mostly (maybe even exclusively) from Borneo.

Now let us examine the following 3 photos:

Vegetatively and in flower they look so different from other Hoyas and so similar to each other that one can almost be excused for thinking that they are one and the same. Even R.E. Rintz, who published an excellent early paper on Hoyas of Peninsula Malaysia, lumped them into a single species - Hoya campanulata.

Now, let's do some closeups of the corona ....

.... the top most plant has a rather fat and succulent corona (the star-shaped protrusion at the centre of the flower). It had been named Hoya wallichii for a very long time until it was recently deemed to be a separate species - H. danumensis, based on some subtle difference. This plant appeared to be confined to Borneo.

The lower 2 plants have slender corona and are collectively lumped under an umbrella called Hoya campanulata - although as I will show later, there appear to be more than 1 species there. This group has a wider distribution, from Malay Peninsula, Borneo, Java and Sumatra.

And here's a portrait of the real Hoya campanulata from Curtis Botanical Magazine, renown for accurate taxonomic depictions of many exotic plants collected all over the world during 1800s. The picture clearly shows the slender corona similar to the latter 2 plants here. It is taken from Simones' excellent web site.

So hopefully, we got these 2 rather different species sorted out.

I shall end this post by flashing another Borneo native that looked like a H. wallichii (or danumensis, take your pick) by virtue of the fat corona, and yet looked distinct in its smaller flatter corolla that curl backwards as shown below :

Any idea what is this ?

Hoya campanulata lookalikes part2

In this follow up post I will focus on the Hoya campanulata complex. An in-situ photo of the plant is shown above; the vine scrambling on rocks, tree trunks and even on the ground of the forested banks of a jungle stream . Beyond twenty metres or so from the stream, it is nowhere to be found - hence one can deduce that it requires very high humidity.

From my conversation with taxonomists and growers, H. campanulata is quite variable in terms of the colour, size and curvature of the bloom. However, this is not in agreement with David Liddle, who had generously shared with me his knowledge until he unexpectedly passed away. Accordingly to him, there is a smaller form known as H. cysthiantha aff (for affiliate)and another form known as the true campanulata.

By the way, the suffix aff was appended because it was believed that the name Hoya cysthiantha was not validly published. However weeks ago Miss Christine Burton told me that Kew had accepted its validity after all.

As you can see from below, these 2 forms are quite different in terms of size, shape and even colour. The yellowish form at the lower picture is believed to be the real H. campanulata while the white one is believed to be H. cysthiantha aff.
Attached below is the closeup of the corona. The yellowish flower on the left clearly showed a more slender and curved corona.
I shall leave it to the taxonomists to argue over this subject - but for me, they are clearly distinct irregardless of their latin names.

For those who does not care much about all this mumbo jumbo, here are a couple of portraits of the attractive flowers. And did I say they smell like lemon too ?

Wednesday, March 9, 2011

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 ....

Sunday, March 6, 2011

Gift from the fallen

Years ago a fallen tree branch from the forest yielded a big rotting clump of orchid on the ground from which I made a cutting and nursed it back to health. Since its full recovery , the Coelogyne pandurata had been rewarding me with this bloom year after year.

This is a large orchid from SE Asia and is often called "Black Orchid" by some due to the fierce looking dark markings on its lips. Although some vendors tried to pull a fast one by touting it to be rare its is actually quite common in lowland forests although it may not always be free flowering.

Friday, March 4, 2011

Alocasia scalprum

Peter Boyce and Alistair Hay officially described this plant in 1999 which has so far only been seen in cultivation with the nickname "Samar Lance". This is the dark form of the variable species known from the island of Samar in the Philippines. While cultivated plants are not uncommon, it is rare or may even be extinct in the wild - no body knows for sure because the island is a hot spot for political unrests and understandably nobody seems keen to survey there.

It differs from the closely related A. heterophylla by its dark coloured cardboard-like leaf blade and a very shallow sinus at the top of the leaf Its a small plant, with adult plant having blades no more than 20cm long. The plane of the leaf lies mostly horizontally which is also quite unlike A. heterophylla, which has errect greener leaves. After growing it for 8 years, I have yet to see it flower for me.

As with most Alocasias, this plant is rather temperamental but I seemed to have to have more success growing in on the ground.

Tuesday, March 1, 2011

How does Heaven look like ?

....I hope its a good place to retire.

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