_P.agnata_ has very short spurs (a few mm) to the corolla and a yellow
palate, the corolla lobes being obtuse and not broadening towards the apex.
The "summer" leaves are generally not upturning at the margin, and they
look like the "winter" leaves.
_P.moranensis_ has very long spurs (always longer than 1 cm), no yellow in
the corolla, the lobes cuneiform and +/- truncate at the apex. The "summer"
leaves are upturning at the margin and they are much larger than the
"winter" leaves.
At least these two species can't be confused with each other.
>Personally I fear that the majority of Mexican pings are either moranensis or
>>agnata :-).
Remember _P.heterophylla_ is from Mexico, too. Most "new" species in
cultivation do belong to _P.moranensis_ or _P.agnata_, however 8-(
Kind regards
Jan