The real problem is when a product based in verum, is adulterated in part with the much cheaper anisatum. This is a serious problem that should be handed by professionals. Only a chemical analysis can identify it.
If you see many hexagonal calcium oxalate microcrystals under a microscope is a red flag of presence of anisatum (but not a guaranteed presence). Beware also that the lack of hexagonal crystals does not guarantee absence of poisonous anisatum in the product. You need a really good microscope to see it clearly, SEM is better, and is a really expensive machine.
Epidermis of seed is said to show a red fluorescence in verum (yellow in anisatum). Endospermum is said to show a blue fluorescence in verum (brown in anisatum). You need specialized lab stuff to see it and this patterns does not occur always so is not a reliable character.
There are differences in striation of cuticle and in shape and size of some specialized cells but they overlap extensively in both species. Unreliable
In resume: if you have the entire seeds the presence of 'big' astrosclereids in the columela tissue are the only reliable character. Branched microsclereids (astrosclereids) over 350 micrometers large is characteristic of verum. If you have a powder made of Illicium, only a chemical analysis can help you.