Does the skeleton come to a point on the bottom (somewhat cone shaped), or is it flat? If it's flat then wellso, but if it comes to a point then trachy. However, this is just a general rule of thu,b and isn't necessarily definitive. Also, the Wellsophyllia radiata is now believed to be a variety of trachyphyllia.
not really sure when I got it about 1 1/2"-2" it was rounded but now it is about 4"-5" it is flattening out. also the orange is allot bigger now and the center looks small compared to the edge
Good question, I'm not sure. Most of the T. radiata I have seen are quite a bit larger (especially when fully expanded), but I have seen some smaller ones on LiveAquaria too.