>I've sometimes wondered what makes Darlingtonia deserve a separate
>genus, rather than just being a Sarracenia with peculiar pitchers.
>Obviously I haven't yet had chance to study the flowers closely, but
>from what I remember, they are fairly similar too. I'm not a botanist,
>just interested, so what in the publication of these genera
>distinguishes them?
1. Range (i.e. not only recent distribution but also a separated
evolutionary history).
2. Perianth, ovary(!), and style(!!) morphology.
>A noteable difference is that the Sarracenia buds are developing on
>a naked stem, whilst what I assume to be a developing Darlingtonia
>bud is on a peculiar structure with leaves/scales on it.
Yes, but _Sarracenia_ peduncles do at least have scales (bracts) just below
the flower (i.e. not the outer perianth lobes but at least a few mm apart
from the flower itself).
Certainly, the two north American genera are closer to each other than any
of these is to _Heliamphora_, but within the three recognized genera of
Sarraceniaceae s.l. (not in the STUDNICKA sense) the species are definitely
closer to each other than to any species outside. Thus, I think the
"traditional" classification is still fully justified.
Kind regards
Jan