12 new carnivorous plant species from the Philippines

Carnivorous plants such as Nepenthes (pitcher plants), which attract, trap, digest and assimilate animals, while looking bizarrely beautiful to humans, have long attracted attention from both scientists and the cultivators of tropical plants. Numerous doctorates have been completed on plant-animal interactions in several species of Nepenthes, and every year recently, one surprising new discovery after another has been made on the mechanisms that these species have evolved in order to obtain nutrients from animals. 

I could write pages on the subject! Yet, I was completely unaware, until I read a recent article by Dona Paranayil in the Independent on Sunday, that there are numerous new, important commercial engineering applications based on the construction of the slippery surfaces of these plants. And only in the last year did I realise that, apart from the commercial market for live Nepenthes species for collectors, there is an even bigger horticultural market in artificial hybrids, which are spectacular and more vigorous in growth than the wild species. (I still campaign to have them removed from Kew’s live science collections - if you are trying to work out one species from another as we taxonomists do, it does not help to have hybrids to contemplate).   

Given the value to humanity of Nepenthes, in terms of the market in live plants, commercial applications for 21st century needs, and perhaps relief from boredom, it seems especially regrettable that species should be going extinct in the Philippines. Most of the 12 new species described in 2013 are threatened and our Nepenthes extincta, published just before Christmas, probably IS extinct already (see the most recent issue of the European Journal of Taxonomy), due to ongoing open-cast mining for nickel which is used in making the stainless steel that we all use. 

Destruction of natural habitat in the Philippines has been huge. In 1925 two-thirds of forest was considered intact (Sohmer and Davis, 2007) while 75 years later it was estimated that only 3% of primary vegetation survived (Myers et al., 2000). Sohmer and Davis estimate that species extinction levels due to habitat destruction in one representative, mainly forest, genus, Psychotria (Rubiaceae), has been between 9 and 28% so far, and habitat destruction continues apace, caused by  oil palm, pineapple and other plantations, as well as open cast mining.  

No other Nepenthes specialist had ever seen most of these specimens, yet several had been collected as long as 100 years ago! Each herbarium had material that was not duplicated at other herbaria. In analysing the specimens, in addition to gross morphology, microscopic examination of the lower surface of the lid of the pitcher (an important part of the trapping mechanism) and for the first time in detail, the precise trichome complements of the surfaces of the pitchers, leaf-blades and stems, proved vital to delimiting the taxa. Inflorescence characters were less useful, perhaps because Nepenthes have only generalised insect pollinators, compared with the often specific animal groups that their pitchers target. 

The outcome of the detailed examination of taxonomically useful characters in these specimens was the astounding discovery that 12 new species had lain undiscovered amongst Kew’s collections. All twelve were formally named and described in 2013 in the publications detailed below. 

Are there more unknown species out there? Almost certainly!