The 'Nepenthes alata group'

[Sockhom]

Hello,

It appears we have now an official 'N. alata group':

- N. alata (Blanco,1837), now restricted to Northern Luzon;
- N. copelandii (Merr. ex. Macfarl., 1908), Mindanao on Mts Apo and Matutum;
- N. graciliflora (Elmer, 1912), Southern Luzon to Mindanao;
- N. mindanaoensis (Sh. Kurata, 2001), Mindanao;
- N. negros (Jebb & Cheek, 2013), Negros and Biliran Islands;
- N. ramos (Jebb & Cheek, 2013), Mindanao in Surigao;
- N. saranganiensis (Sh. Kurata, 2003), Sarangani.


That group would be defined by the following features: 'a basal appendage on the lower surface of the pitcher lid; a terete stem, a distinct, but winged petiole, the petiole wings patent and spreading, decurrent from the blade; the peristome finely ridged, the outer edge not or only slightly lobed, the inner surface lacking conspicuous teeth; the mouth ovate, oblique, without a well-developed column.' (quote from the N. ramos paper).

More on this here:
carnivorousockhom.blogspot.fr/2013/08/the-nepenthes-alata-group-resurrection.html

Feel free to debate here. I would especially be interested to hear the insight of the people who grow/saw/studied 'alata plants' in the wild.

All the best,

François.


PS: Bob,I have strictly kept what could be loosely regarded as 'personal attacks'on my blog. That said, I would perfectl y understand if you do not like the tone of this post and decide to moderate / delete it. François.

[John Brittnacher]

François, you know that almost by definition, formal taxonomy is a method for filing dead organisms into boxes in a museum. It may or may not make sense with respect to real life and there is nothing to say it has to. I have been faced with this reality since I was in graduate school (and not working with plants). Now I have gotten to the point where I just roll my eyes and move on. Well, OK, sometimes I do get a little hot too. It is frustrating to be working on some group of organisms and not having a set of names that make sense.

According the rules of the taxonomy game, the next step is for someone to go into the field and make more collections demonstrating that in fact there are intermediates between each of these "species". Or even better yet, collecting even more specimens and doing a huge multivariate analysis showing whether or not the existing variation falls into associations or not. But as you point out, you can probably bring those plants into a different environment and get different results.

If all else fails, you can just ignore all these names and/or write your own world list of Nepenthes species.

[ICPS-bob]

François, why would we delete your post? Vigorous debate and differences of opinion is what makes science robust. We strongly discourage personal attacks of a vicious nature. But, well reasoned discussion is not only tolerated, it is welcomed. Taxonomy, in particular, is opinion. Over time, differing opinions tend to converge, but not always.

[marcel]

Couldn't agree more so nothing to add to my two colleagues

[John Brittnacher]

The problem with these arguments about whether you have a hyper-variable species, a species group, or a massive hybrid swarm in genera like Nepenthes where there are no reproductive barriers between species is there are no objective methods for making a decision which it is. Of course you could revert to molecular studies but that is only useful if it actually confirms what you already want to believe. Chances are it will muddy the waters even more.

Robert Gibson did a massive study of the Drosera peltata species group with cluster analysis of measurements on dead plants. Even after good results his revisions of the group are not widely accepted yet. Some people don't think the differences he found are great enough even if they are statistically different.

I don't know anything about the supposed Nepenthes alata group but I do know about Sarracenia. We have the situation where the recently published Flora of North America treats the Sarracenia rubra species group totally different from the recently published Sarraceniaceae of North America. The authors of both publications have valid reasons for their decisions. It doesn't do any good to look at the ICPS sites for guidance because for exactly the same reasons the two books disagree, you will find different answers by different ICPS-associated authors. I have my personal preferences but they are not guided by dead plants. One criterion I call the 20/20 rule. If you can tell live plants apart at 20 feet they are different species. Another related approach is how they grow and flower. Under these criteria there are 6 species in the Sarracenia rubra species group. Again these are live plant observations and taxonomy is dead plants. My way of deciding personally on these plants is not valid taxonomically. I don't consider that my problem.

[Dave Evans]

Aug 29, 2013 2:48:38 GMT John Brittnacher said:

Robert Gibson did a massive study of the Drosera peltata species group with cluster analysis of measurements on dead plants. Even after good results his revisions of the group are not widely accepted yet. Some people don't think the differences he found are great enough even if they are statistically different.

I have been waiting for this paper... I must have missed it somehow...?

[Dave Evans]

Aug 29, 2013 2:48:38 GMT John Brittnacher said:

The problem with these arguments about whether you have a hyper-variable species, a species group, or a massive hybrid swarm in genera like Nepenthes where there are no reproductive barriers between species is there are no objective methods for making a decision which it is. Of course you could revert to molecular studies but that is only useful if it actually confirms what you already want to believe. Chances are it will muddy the waters even more.

Hello John,

I can't say this statement makes much sense to me. Maybe if one wasn't familar with Nepenthes, you might have an idea like this, from studying other plants that do do this, but Nepenthes clearly maintain species and do not tend to form hybrid swarms.

Lately, human habitat destruction has been applying pressure on many species, pushing them together in marginal habitats in which none of the species are evolved to deal with specifically. In these unnatural conditions, hybrids can have an advantage.

[marcel]

Aug 29, 2013 20:44:39 GMT Dave Evans said:

Aug 29, 2013 2:48:38 GMT John Brittnacher said:

Robert Gibson did a massive study of the Drosera peltata species group with cluster analysis of measurements on dead plants. Even after good results his revisions of the group are not widely accepted yet. Some people don't think the differences he found are great enough even if they are statistically different.

I have been waiting for this paper... I must have missed it somehow...?

Ask and you will recieve...
www.publish.csiro.au/paper/SB11030.htm