Nepenthes eymae /nɪˈpɛnθiːz ˈeɪmaɪ/ is a tropical pitcher plant endemic to Sulawesi in Indonesia, where it grows at elevations of 1,000–2,000 m (3,300–6,600 ft) above sea level.

[7] Nepenthes eymae was formally described by Shigeo Kurata in a 1984 issue of The Journal of Insectivorous Plant Society.

[2][8] The holotype, designated as Kurata, Atsumi & Komatsu 102a, was collected on the northern spur of Mount Lumut in Central Sulawesi,[9] at an altitude of 1850 m, on November 5, 1983.

[7] The repository of these four specimens is not indicated in the type description and they have not been located, but if they were deposited in a public institution this is likely to have been the herbarium of the Nippon Dental College (NDC).

[7] Despite this, the species name is valid per Article 37 of the International Code of Botanical Nomenclature, and Kurata's description includes an illustration of the holotype on page 44.

[7] Almost concurrently with Kurata's publication, John Turnbull and Anne Middleton described the same species under the name N. infundibuliformis in the journal Reinwardtia.

[6][7] Turnbull and Middleton's description is based on the specimen J.R.Turnbull & A.T.Middleton 83148a, which was collected by the authors on September 20, 1983,[note a] from Mount Lumut Kecil in Sulawesi at the coordinates 1°03′S 121°41′E / 1.050°S 121.683°E / -1.050; 121.683, at an altitude of 1500 m.[7] In their description of the species, Turnbull and Middleton stated that the type material was deposited at Herbarium Bogoriense (BO), the herbarium of the Bogor Botanical Gardens, but Matthew Jebb and Martin Cheek were unable to locate it and wrote that it "appear[s] not to have been deposited at Bogor as stated".

[note b] Most authors regard N. eymae as a distinct species and it has been treated as such in all major monographs on the genus, including Matthew Jebb and Martin Cheek's "A skeletal revision of Nepenthes (Nepenthaceae)" (1997)[10] and "Nepenthaceae" (2001),[4][7] as well as Stewart McPherson's Pitcher Plants of the Old World (2009).

[4] Whatever the status of this taxon, the vast majority of plants cultivated under the name N. eymae do not exhibit the abruptly contracted upper pitchers commonly associated with it.

[13] Nepenthes eymae is a climbing plant growing to a height of up to 8 m.[4] The stem, which may be branched,[4] is two-ridged and up to 8 mm in diameter.

[4] It clasps the stem for around half of its circumference and is abruptly decurrent, sending off a pair of low ridges to the node below.

A pair of wings (≤2 cm wide) is present on the ventral surface of the pitcher cup; the fringe elements are up to 8 mm long.

[4] Characteristically, the hollow pitcher tube continues past the curved basal portion of the trap and for a few centimetres up the tendril.

The peristome is flattened,[7] glossy and up to 1.5 cm wide, being of approximately equal width across its span[4] or broader towards the rear.

Developing pitchers have laterally appressed walls and a pronounced bulge at the rear, which holds the spur upright.

[4][7] Upper pitcher are predominantly yellow, sometimes bearing red to purple flecks on the inner surface and lid underside.

Nepenthes eymae has no confirmed natural hybrids, although introgression may take place where this species is sympatric with N. maxima.

[1] In 2009, Stewart McPherson wrote that the species is "widespread and locally abundant" across its range and that most populations are "remote and not seriously threatened at present".

[4] Nepenthes eymae is known to occur in one protected area (Morowali Nature Reserve), although the full extent of its range is unknown.

[4] Nepenthes eymae produces an extremely thick, mucilaginous pitcher fluid that coats the entire inner surface of the traps in a thin film.

[6] A 2011 study that used cultivated material of N. eymae recorded a mean digestive fluid relaxation time of 0.096 seconds (± 0.000) for this species.

[16] As for the majority of studied highland Nepenthes (but not lowlanders), this value differed significantly (P < 0.001) from that of distilled water, leading the authors to categorise N. eymae as a viscoelastic species.

[16] Similarly viscous pitcher fluid is found in the group of closely allied Sumatran species that includes N. aristolochioides, N. dubia, N. flava, N. inermis, N. jacquelineae, N. jamban, N. talangensis, and N. tenuis.

[17] Nepenthes eymae is very closely allied to the extremely polymorphic N. maxima, which is widespread across Sulawesi, New Guinea, and the Maluku Islands.

While some forms of N. maxima also produce entirely infundibular aerial traps, these are not usually as abruptly contracted (and therefore wine glass-shaped) as in N. eymae, and may or may not have fringed wings.