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Pitcher Plants

jimscott

Tropical Fish Enthusiast
Are the Sarracenias, Heliamphoras, Nepenthes, and Cephalotus plants related to one another or are they from different areas of the earth that evolved to occupy the same niche? Analogous or homologous?
 
Nepenthes and Cephalotus are both in their own families. I'm not sure how they're related above that classification. Sarracenia, Heliamphora and Darlingtonia are all in the same family. I could be wrong, but I think Heliamphora is supposedly the most primitive of the 3. As far as evolving to occupy the same niche, I'm not sure the 3 families occupy the same niche. Yes, they all evolved carnivory, but I think the plants in the Cephalotus family,Nepenthes family, and Sarracenia family occupy different niches. I think the carnivory is an afterthought, so to speak.
 
Even Sarracenias don't all occupy the same niche. Their ranges do overlap, but S. purpurea can go much further north, S minor can go further south (I think), S alata can go further west, and so on. S purpurea can go just about anywhere a Sarracenia can go, but has a much less effective trapping mechanism than the others. I guess S. leucophylla has the smallest range, but what an effective trap they have. Geographic range doesn't equal niche, but it's an aspect of it.

There is even more variation among Neps, I suppose.
 
I was thinking in terms of bogs and carnivorous features.
 
Sarracenias, Neps, etc. evolved pitchers independently as a solution to nutrient limitations. Nutrients, especially fixed nitrogen, are scarce in temperate bogs due to denitrification, leaching, and the limited supply delivered by precipitation. But I remember reading years ago that CPs are absent from the most severely N-deficient temperate bogs. That would suggest they trap insects for something other than N. I wish I could remember the details.  I suspect I saw it when doing research for biogeochemistry or physiological ecology term papers I used to write.  Since I wasn't focused on them, I doubt I ever recorded the source.
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