It is more than likely a sales gimmick with the name 'Tamaya'. What I could find on the web has some mention of it but according to Steve's Leaves, it is more than likely B. albo-picta ‘Rosea’.

https://stevesleaves.com/tamaya-or-not-tamaya/

http://ibegonias.filemakerstudio.com.au/browserecord.php?-action=browse&-recid=17009&p=photo&-recnum=1

The second link looks like a garden variety B. coccinea var. hort. which I have plenty of - red, pink, and white blooming varieties.

Begonia seedlings all start out the same - small leaves until they are big enough to start differentiating on what they will eventually become. B. semperflorens aka wax begonias will develop a bit of a stem but nothing like a cane begonia. Once they hit a more mature growth, you will plainly see what they are and what they are not. I have a weedy wax type begonia that always comes back from seed outdoors without a care in the world. Well, I did have to water it some this summer since we had drought of many weeks - August through a hot early October.

To post photos - note the icons below the text box (B, I, bullet points, Photo, etc.) Click on Photo and browse to the photos you want to include (you can add them later with an edit). To make life easy, make sure your photo has been resized to say 8" width with a small resolution - this will downsize your photo to less than 500 KB which is perfect for online posting. If you do the original size, the download may time out and you will lose your message. Another good reason to submit your message first and come back to include photos with an edit. You can add ten photos per post which is a far cry from the way GW used to be. I use FastStone image resizer and do all the photos in a folder at one time and have the output go to a child folder called "email" under the parent folder. This makes life so much easier. FastStone resizer is freeware but I did send the developer $20 after I had used it for a couple of years.

seeds germinate quickly if they are viable (fresh works best but some people say they've germinated seed in the refrigerator over ten years old)

Problem is moving them up to a bigger pot - HAHA! A lot will die off from being shaded out by the more vigorous seedlings.

You still need to move these up as well. Unless you are just playing around like I have done, it is much easier to get beautiful begonias from many different sources (online, local nurseries, trades, and best of all - join the American Begonia Society and buy some seed).

Here is a tray of cuttings and seedlings I tried a few years ago - most of the seedlings died - too wet or too dry or simply not enough strength to compete with the cuttings when they sprouted.

The small bright green pellets are begonia seedlings.

a cane seedling which are the easiest - just came up on its own.

and then my cane seedlings that I grew from harvested seeds from my mother maculata plant.