A New Nepenthes species… from Australia?

[Source]

Those well-versed in Nepenthes geography should be somewhat familiar with the three Nepenthes species of Cape York, namely N. mirabilis and the two endemic species, N. rowaniae and N. tenax. However, that wasn’t always the case — Frederick Manson Bailey, a prominent botanist in the flora of Queensland, described 10 endemic species to the Cape York area from 1881 to 1905 (numbers are links to herbarium specimens):

N. albolineata (1898) [1] = N. mirabilis
N. alicae (1898) – note the small stature [1] = N. mirabilis
N. armbrustae (1905) [1] = N. mirabilis
N. bernaysii (1881) [1] = N. mirabilis
N. cholmondeleyi (1900) – note the small stature [1] = N. mirabilis
N. garrawayae (1905) [1] = N. mirabilis
N. jardinei (1897) [1], [2] = N. mirabilis
N. moorei (1898) [1] = N. mirabilis
N. pascoensis (1905) [1] = N. mirabilis
N. rowaniae (1897) [1]

Plus von Mueller’s contribution:

N. kennedyana (1865) = N. mirabilis

made for a total of 11 endemic Australian Nepenthes; Nepenthes mirabilis brings the tally up to 12 (for a sense of scale, there are 13 species of Nepenthes in Sulawesi). In 1928, Danser’s monograph The Nepenthaceae of the Netherlands Indies synonymized all of these species with N. mirabilis (including N. rowaniae). Field work by Clarke and Kruger (2005) led to the reinstatement of N. rowaniae (which is now typically accepted) and the description of a new species, Nepenthes tenax; leading to what we generally accept today.

Bailey’s original drawing of N. rowaniae, 1897 [SOURCE]

Nepenthes kennedyana (=mirabilis) in The Gardeners’ Chronicle, 1882 [Source]; this name was also applied to specimens from New Guinea

But now, it appears we can add a 13th Nepenthes to the list from Cape York with the description of Nepenthes parvula (Gary W. Wilson and Stephanus Venter, 2016) in the journal Phytotaxa. N. parvula is separated from N. tenax by its smaller vegetative and floral stature (which the authors claim is maintained in cultivation; adult pitchers up to 50 mm, cylindrical instead of infundibular in N. tenax) as well as its higher gland density, red coloration on the lid underside, and its ecological preference for continuously wet conditions. The authors also note that spent leaves remain on the stem, forming a “skirt” of leaves (much like an adult Drosophyllum). Apparently, the species is occasionally sympatric with N. mirabilis, N. rowaniae, and N. tenax.

Nepenthes tenax, photo by Stewart McPherson; unsurprisingly, this taxon also has the red lid underside mentioned in the paper

So what can we make of this “mini-tenax“? In my unqualified opinion, there certainly isn’t enough justification to separate Nepenthes parvula from N. tenax when taken in the larger context of Nepenthes taxonomy. Larger morphological differences haven’t led to such separation (e.g. N. mirabilis var. globosa — which was somewhat controversial too, as many called for its elevation to species status, but has never been contested). Can these cultivated specimens prove that N. parvula isn’t just a stunted, neotenic, or geographical form of N. tenax? Without further details from the authors, I’m highly skeptical of this new taxon. Furthermore, it would be interesting to see if the authors reviewed Bailey’s herbarium material, because two of his species, N. alicae and N. cholmondeleyi, appear to be very small forms of Cape York Nepenthes as well. Time will tell.

Photograph from the Australian Tropical Herbarium Facebook page

More photos of N. parvula in situ can be found here: link

Photograph from the Australian Tropical Herbarium Facebook page