Fruits of Simpoh

There are 2 types of fruits that occur in the genus of Dillenia. There are the indehiscent fruits as well as the dehiscent fruits. However, it is still hard to determine which evolves first. Logically, the dehiscent fruits are assumed to be more primitive compared to those indehiscent ones. The arillate seeds as compared to ex-arillate seeds also tells us a different story on this genus. Almost all of the dehiscent fruits are covered by the red aril or soft red membrane; however i didn't get the chance to check all of them in field yet. Somehow, it is true for D. suffruticosa (below) and D. excelsa. Four species of Dillenia consists of D. suffruticosa, D. excelsa, D. pulchella & D. albiflos in Peninsular Malaysia have dehiscent fruits while the rest of the six species have indehiscent fruits. The arillate membrane are unnoticeable under herbarium specimens as they dried off as a thin transparent sheet of membrane.

Meanwhile, in the indehiscent fruits, i managed to find two types of seeds which are arillate as well as exarillate. Till now, i had only few chances to disect a few species of fruits for inspections. I found out that D. indica have soft white membrane covering its seeds meanwhile D. ovata and D. reticulata has ex-arillate seeds. A little contradictory to what literature reviews written that D. reticulata have arillate seeds. Below are photos of the fruit of D. reticulata that i disected recently for inspection in field. I found out that the fruits of simpoh when being freshly cut had a tinge smell of guava. The young fruits of simpoh are green in colour and will turn yellowish-green to orangey when ripe. The rotten fruit will turn brown and later on black. The seed on the other hand are white when young and turning into brown to black when matured. According to Corner that had done the study on the infloresences of Dillenia, he found out that the evolutionary of the flowers and fruits are reticulate and both flowers and fruits evolves separately. For me, i think much characters still needed to be inspected before one can determine the phylogenetic relationships of the species in this genus.

D. ovata in bloom!

On my recent trip to Taman Negara, i was delighted to be able to witness a bloom of Dillenia ovata. The stamens are as what i had expected. They are hardly differentiated into two rows. The stamens are yellowish while the carpels are white. There are abundance of this species in the area. Much of them are fruiting and some flowering or still in bud stage. I also managed to bump into other 'simpoh' species that are fruiting such as D. reticulata and D. grandifolia besides D. ovata on the new trail being built that link the hind of intepretive room towards Bumbun Hide that link through the swamp loop. Below is the photo of D. ovata on the new trail.

Flowers of simpoh

Basically, the most powerful source of recognizing Dillenia to its' species is through its flower. However, when you are in a hurry, you might not be lucky enough to bump into a flower no matter how frequent your visits are. That's what i went through in my crazy venture looking for Dillenia. This is because simpoh tree have odd flowering period and sometimes you will only find one tree flowering or fruiting while the rest are in a sterile state.

However, don't be too frustrated though. I found out from my analyses lately that we can actually differentiate the species of Dillenia through it's vegetative organ such as petiole, type of venation, the indumentum on the leaves as well as the colour of dried leaves. So far, i'm positive that this is enough to help to determine Dillenia species in Peninsular Malaysia.

As far as i'm concerned, i found out that generally Dillenia flowers are found in two forms. The two forms are:

1) The anther are approximately almost the same length and not clearly divided

2) The anther are divided into two groups where the inner stamen are longer with its' apex a little bit curved outwards while the outer stamens are shorter

If you noticed, you'll found out from the photo above that the sepals of simpoh are divided into tow types where the Dillenia species with dehiscent fruits have thin sepals while the species with indehiscent fruits are of thick sepals. Guess you can figure out from the picture which belong to which right? From top view, we can see that the carpel look like a spreading star (D. indica; top). The purple colour of the stamens is a very distinctive character only occur in D. excelsa that differentiate it from other species in Peninsular Malaysia.

Latest discovery!

I'd currently completed my write-up and throughout my analysis, i found out that i had misidentified two species that i'd formerly collected on field. This causes me to go into havoc in search for that species; D. sumatrana as time is scarce and i had to repeat my anatomy work. In order to do things fast, i am lucky to be able to set foot on the nearest forest in UKM itself (Bangi FR) in search of the species. It took me two trips into the forest before i manage to bump into this tree. On the left is the photo of me and two of my helpful friends that i'm indebted for their willingness to accompany me to the forest and they even help me climbed up the tree to get some leaves as my voucher speciments. For acknowledgement, the species that i'd collected in Kuala Lompat that i referred as D. sumatrana earlier is actually D. excelsa while the tree i thought to be D. excelsa which i bumped into on my first trip in search of Dillenia in Ayer Keroh, Malacca had turn out to be other species and not Dillenia. What an experience! That is why it is quoted by previous taxonomist who deal in Dilleniaceae that it is hard to identify Dillenia species without reproductive structure and it is almost worthless if we have only sterile speciments. I agree with him pretty much. Bravo to all taxonomists!