The best way to ID any given species is through DNA analysis, although this is not so frequently done by many people. Most simply don't have the access. Flowering will not tell you accurately, since many plants(most organisms, for that matter)share nearly identical phenotypes; it is in their genotypes that hold the key to their identification.
Furthermore, over the years even wild type Crypts have cross-bred for who knows how long or how much. Any particular Crypt we have is likely a result of cross-bred specimen. Unless you can pin-point its P1, F1, F2,....basically its geneology, it is too hard to be able to narrow down to the species level, without molecular analysis.
Paul