I had a look at that site but I'm really skeptical of those claims. There's 418 accepted species of Garcinia but as far as I'm aware there's no Garcinia species in Japan. Not that I've checked them all out. Perhaps they mean it was a cultivar developed in Japan. They look like a slight aberration of the normal Garcinia mangostana, and I suspect that's what they are. The nurseries here sell some species of Garcinia that are claimed to be smaller and earlier fruiting than G. mangostana. But the fruit is also fairly different. For the price they're asking for 6 seeds you could buy about 4 plants of the 'smaller, earlier flowering ones' in 200mm pots. There's probably some people prepared to give them a try though. Would be interesting to see what they thought later.

That's true, for the price they're asking for you could have bought a few small plants of the other different garcinia species. I did do a little research and found a thread about this kind of mangosteen with picture on the other tropicalfruitforum

someone on there said it's called a "masta/mesto mangosteen"

I'm ashamed to say this, but I must admit, I'm one of those somebody that actually forked over $60 bucks for those seeds:(

I found that forum after I already bought them, so for now....my thoughts would have to be later much later if I mange to keep them alive that long since i don't even have a green house

Here is a link that might be useful: Masta mangosteen

I've done a bit of reading on this, there are variations within the G. Mangostana; including color, size, and shape based on geography.

Mature at two years don't sound like G. Mangostana.

I doubt that there are any varieties that can survive a Japanese winter with out assistance.

Any Mangosteen seed purchase though the mail would be risky, and I believe that are not even in season right now, so extra risky.

Soaht,
Did they germinate?

After further review, they are in season depending on where you are.

Doglips-
I haven't received them yet, just order them when I post this thread. It is coming from Singapore so may take a week or 2. The seller has great reviews, so I hope I didn't get juked by a false seller. As they're are many false Borneo seed sellers on ebay base on one of the forum I saw.

" Forty-nine Garcinia species have been recorded in Malaysia (Whitemore 1973), and 30 of these species have edible fruit, of which G. mangostana is the most important one producing round fruit with slightly flat distal ends and naturally seeded, referred commonly as "manggis". The other less common type of mangosteen, known as "Mesta", produces obovoid fruit with slightly pointed distal ends (found in Pahang and Sabah, Malaysia) have very thick mesocarp and are mostly seedless or have undeveloped seed. "

http://www.itfnet.org/contents/fruit/fruitInfo/html/trdLevel1511.html

Apparently "mesta" is extremely close in appearance to the regular "manggis" mangosteen variety, at first glance a bit hard to differentiate.

also from the same previous article:

" Technically, the so-called "seeds" are not true seeds they are adventitious embryos, or hypocotyl tubercles, in as much as there has been no sexual fertilization. Because the seed does not arise from fertilization, genetic variation was thought to be almost non-existent. Since the seed arises from the cell wall of the female flower and is effectively a clone of the mother tree, the seedling has her genes intact and unchanged for generation after generation. Several experiments have been conducted taking advantage of the most current DNA and RNA analysis techniques and it turns out that there is significant variation globally amongst the different populations of the mangosteen. There is a large proportion that has essentially the same genetic make-up (genotype) but there are significant numbers that do not. "

So slightly different varieties of Mangosteen (G. mangostana ) are known to exist.

Of course this would not truly be "Japanese Mangosteen", that would be Garcinia subelliptica, which is indeed native to the Southern Japanese island of Okinawa, Taiwan, and the Philippines. In Japan it is known as Fukugi.

http://www.asianplant.net/Clusiaceae/Garcinia_subelliptica.htm

fruits are yellowish to orange, although I find no mention to them being edible, however okomori bats eat the fruits off the trees at night

" Here’s more info on the Mangosteen we eat which is Garcinia mangostana – referred to as the Queen of Fruits. It is thought that mangosteens we eat originate from a natural hybridisation of two species Garcinia malaccensis and G. hombrioniana. It is quite surprising that the mangosteen reproduces from seeds which are not fertilised (a phenomenon called apomixis). This means that the mangosteens we eat are genetic clones of the first natural hybrids. But there are variations that occur in the mangosteen so it is plausible that the mangosteen arose from different hybridisations and not from one. One such cultivar is given the cultivar name ‘Mesta’ (so in full it would be Garcinia mangostana ‘Mesta’. You will find it in some mangosteen shops being sold as Japanese mangosteens. These have a “sharp pointed bottom” as described in the blog i eat i shoot i post. (Botanical term for such a shape – obovoid). This particular cultivar has very tiny seeds so it feels like it is seedless! "

https://lovemacritchie.wordpress.com/2015/10/01/10-amazing-plants-in-our-macritchie-forest/

" Another gem that you can find at 818 Durians is their very special “Japanese” Mangosteens. If they are available, make sure you grab a bag. These Mangosteens are easily recognized by their sharp, pointed bottoms as compared to the usual Mangosteens which are round. The flesh is crisp, sweet and tangy and amazingly, there the seeds are so small that most of them are edible! I found that you might get one seed that you would need to spit out in every Mangosteen you split open! It’s the best Mangosteens I have ever come across! "

I posted some pictures in this thread: "Mangosteen may not be a true species"

It appears that these "Japanese mangosteens" are real, although they're not Japanese.

Not unusual for plants to get an incorrect geographic tag in their common name. It's all to do with marketing rather than anything to do with accuracy. Look at all the plants that have "Hawaiian" in their name but come from anywhere but Hawaii. It's just marketing.