18 January 2009

Mangrove mysteries at Pulau Semakau

Inspired by Dr Jean Yong to take a closer look at mangrove trees at Pulau Semakau, today I really examined closely some of the trees I came across.This intriguing Avicennia is different from the 'standard' Avicennia alba. But Dr Jean Yong did emphasise with many examples during our earlier walk, that Avicennia alba can take different forms especially if they are shaded, or lack nutrients or face other difficult circumstances.

Nevertheless, I take a real close look at the fruits and flowers.And here's an even closer look.Square stems, big flowers, the fruits that odd shape. Hmmm...The tree is tall (about 2-3m).With long pointy pneumatophores. I couldn't quite get a photo of the bark though.

Nearby was another tree also with intriguing flowers and squarish stems.
A closer look.And another flowering branch.And a bunch of tiny developing 'fruits'.
Here's a closer look.
The tree was standing all by itself and was also quite tall, about 2-3m.Here's a closer look at those pointy pneumatophores.Both trees were growing in a shallow almost enclosed lagoon, at the furthest end from the inlet for seawater.

My new found love affair with Avicennia marina makes me see one in every odd Avicennia. But I hesitate to say anything until Dr Jean Yong kindly has a look at these photos. They are probably just another variation of Avicennia alba. Sigh! [Afternote: Dr Jean Yong has kindly confirmed that both trees are Avicennia marina!!! This is way too exciting!]

There was a pretty little treelet nearby with fresh green leaves and pinkish tinges.
I recall Dr Jean Yong showing me that the faint pink blush at the tips of the leaves are a sign that this is Sonneratia alba.Indeed, there were slight pinkish bits (at yellow double arrow), not so obvious in the photo.

The obsession with rare mangrove trees makes me poke Eric and Marcus into taking common Bruguiera. Sorry guys!
Here's one that got me excited. With the sepals spreading. But this is probably just the common Bruguiera cylindrica which has sepals pointing upwards. These propagules are probably still young and as they grow up, the sepals will start to point upwards?A look at the beautiful flower of the tree.And some really young propagules just starting out.

A blossoming Bruguiera gymnorrhiza tree is one of the most arresting sights in the mangroves.The bright red, thick sepals which Dr Jean Yong says are like lipstick, really brighten up the mangrove forest. The actual petals of the flower are thin, brownish and delicately fringed. The petals are spring loaded to explode and annoint visiting sunbirds with a puff of pollen on their heads. The petals soon fall off leaving behind the thick plasticky sepals.

Next to the sea wall, wedged among the replanted mangroves was a nice Ceriops tree.
Dr Jean Yong had earlier explained that Ceriops tagal is identified by a white collar around the propagules (long thing growing out of the 'fruit'). This one didn't have the distinctive white collar but it's probably Ceriops tagal. It has a smooth brown 'fruit'.

I'm so thrilled Dr Jean Yong has confirmed that the little Ceriops I saw yesterday is Ceriops zippeliana and that this is the first record of this tree for Pulau Semakau!Ceriops zippeliana has a textured 'fruit'. WOW, cool! Additionally, Dr Jean Yong shares that Ceriops tagal flowers have much longer stalk (normally more than 1 to 2 cm, often longer in deep shade) while Ceriops zippeliana flower stalk is often less than 0.5 cm and is very close to the stem, unlike Ceriops tagal.

To get me even more excited, Dr Jean Yong has just kindly shared that we should be on the lookout for yet another species of Ceriops which has yet to be recorded for Singapore. Ceriops australis has a red collar ("Motor cycle helmet" clayx shape) BUT without the characteristic patterning of Ceriops zippeliana! Wah! Makes me want to go right back in to the mangroves to go look some more.


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