This is the ‘Red’ form of longiciliata and does grow true from seed (no variation in my batch of seeds, at least).  It is covered in a large prickly hairs and can get leaves the size of a dinner plate with time, but it often stays much smaller in terrarium conditions.  In a greenhouse, it will grow larger.

For those of you who have been in the hobby a little while, this species used to be named sizemoreae, until it was found the ‘typical’ sizemoreae was actually a unique variety of longiciliata.  Prior to that, it was known as Begonia U388.

From begonias.org,

“B. U388 was collected in North Vietnam November 6, 1996 by Mary Sizemore. It was growing terrestrially on the bank of a river near Hanoi…. in the American Begonia Society’s Unidentified Species Listing compiled by Freda Holley, there is as listing for B. 0388 but no date and no data. Going through The Begonian from 1999 through the latest publication of 2003 the only reference was in 2000. This leads us to believe it was given its number sometime in 2000.”