>Could someone please tell me what the difference between these
>two species is.
_P.parvifolia_ is a smaller edition of and closely related to
_P.heterophylla_ (ill-defined and perhaps not distinct at specific rank).
It has small (name!) long, narrow and obtuse (-acute?) summer leaves, and
flowers with a short spur.
_P.rotundiflora_ is a very distinct species. It has broad, few, almost
circular summer leaves, many small, lingulate winter leaves, a completely
(!) glabrous scape, flowers which are round in outline (name!), with a spur
of intermediate length (up to 1 cm), and very distinctive hairs in the
throat (with a berry-like head, use a lens or microscope!). It can hardly
be confused with any other species when in flower.
Kind regards
Jan