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| Nepenthes maximoides Cheek, in King & Cheek, 2020. DOI: 10.7717/peerj.9899 |
Abstract
Nepenthes maximoides sp. nov. (Sect. Alatae) is described and assessed as Critically Endangered (Possibly Extinct) from Luzon, Philippines and appears unrecorded in 110 years. The spectacular, large, narrowly funnel-shaped upper pitchers, lids with recurved basal and filiform apical appendages, unlike any other species in the Philippines, closely resemble those of N. maxima (Sect. Regiae) of Sulawesi–New Guinea, likely due to convergent evolution. Following recent phylogenomic analysis, sect. Alatae is divided into two, Sect. Alatae sensu stricto of Luzon to Sibuyan (including N. maximoides), and Sect. Micramphorae, expanded and recircumscribed to encompass those species of the southern Visayas, and Mindanao. A key is provided to the six species now recognised in the newly narrowly recircumscribed Sect. Alatae. The number of Nepenthes species recorded from Luzon has increased from two in 2001, to eight in 2020, all but one of which are endemic to that island, and four of which appear to be point endemics.
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| Figure 1: Nepenthes maximoides Cheek. Photo of the type specimen Curran s.n. (Univ. Pennsylvania sheet 70707), PH. Note that material is mounted pitchers facing downward. Photo by Martin Cheek. |
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| Figure 2: Nepenthes maximoides Cheek. (A) Habit, showing climbing stem with two upper pitchers; (B) exterior of upper pitcher showing junction of peristome, lid and spur.; (C) lower surface of the lid of the upper pitcher showing basal and apical appendages; dotted line indicates outer limit of nectar glands which are absent from the lid margin; (D) detail outermost lid nectar glands on underside lid; (E) detail lid nectar glands near/on basal appendage (same scale as D); (F) detail basal appendage with gland distribution; (G) detail apical appendage; (H) minute branched and stellate hairs of lid margin; (I) peristome near lid, viewed from exterior; (J) inner edge of peristome near lid; (K) peristome of upper pitcher, transverse section, outer surface of pitcher to the right; (L) midrib of leaf blade, adaxial surface, showing simple hairs; (M) sessile depressed-globose glands on abaxial leaf-blade surface; (N) margin of young leaf-blade showing hairs (all: Curran s.n. Univ. Pennsylvania sheet 70707). Drawn by Andrew Brown. |
Nepenthes maximoides Cheek, sp. nov.
Differing from Nepenthes graciliflora Elmer in the upper pitchers narrowly infundibulate, widest in the distal half at the peristome (not ovoid-cylindric, widest in the proximal half), the peristome broad, flattened, and lobed on the outer edge (not narrowly cylindrical and entire on the outer edge), the lid with an asymmetrically hooked basal appendage and a filiform apical appendage (not symmetrical non-hooked, and absent, respectively).
Type: Curran s.n., Herb. Univ. Pennsylvania sheet number 70707, Academy of Natural Sciences Philadelphia sheet number 01113309 (holotype PH; isotype PNH destroyed, not seen), Philippines, Luzon, ‘Tayabas Province’ (deduced to be Mt Banahaw, Quezon Prov.) st. December 1911.
Etymology. Meaning that the species looks like Nepenthes maxima Nees (since it looks so similar to this species that it was confused with it).
Conclusions:
The dramatic rise in the numbers of Philippine species of Nepenthes in the 21st century (see “Introduction”) is mirrored in other plant groups such as Rafflesia R.Br. (Rafflesiaceae). Before 2002 only two species of Rafflesia were thought to be known from the Philippines (subsequently two additional, long-overlooked species came to light), and, as in Nepenthes, the genus was thought to be most diverse in Borneo and Sumatra. Intensive fieldwork in remaining patches of forest in the Philippines, however, has raised species numbers steadily from two species in 2002 to 13 species in 2019, and Philippines now is the most species-diverse country for Rafflesia globally (Barcelona, Pelser & Cajano, 2007; Barcelona et al., 2009; Pelser et al., 2013, 2019).
The number of flowering plant species known to science is disputed (Nic Lughadha, Bachman & Govaerts, 2017), but a reasonable estimate is 369,000 (Nic Lughadha et al., 2016), while the number of species described as new to science has been at about 2,000 per annum for at least 10 years (Cheek et al., 2020). The conservation status of 21–26% of plant species has been established using evidence-based assessments, and 30–44% of these rate the species assessed as threatened, while only c. 5% of plant species have been assessed using the IUCN (2012) standard (Bachman, Nic Lughadha & Rivers, 2018). Newly discovered species such as Nepenthes maximoides, are likely to be threatened, since widespread species tend to have been already discovered and it is the more localised, rarer species that remain to be found although there are exceptions such as Gouania longipedunculata Cahen, Stenn & Utteridge (2020) which is widespread. This makes it urgent to discover and protect such localised species before they become extinct due to habitat clearance as was the case with Nepenthes extincta Cheek & Jebb (2013a). However, it may be too late for Nepenthes maximoides, which may be extinct already, although efforts to rediscover it should be made in case not.
Charles King and Martin Cheek. 2020. Nepenthes maximoides (Nepenthaceae) A New, Critically Endangered (possibly Extinct) Species in Sect. Alatae from Luzon, Philippines showing Striking Pitcher Convergence with N. maxima (Sect. Regiae) of Indonesia. PeerJ. 8:e9899. DOI: 10.7717/peerj.9899
