| Nepenthes villosa | |
|---|---|
 | |
| Upper pitcher ofNepenthes villosa fromMount Kinabalu | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Nepenthaceae |
| Genus: | Nepenthes |
| Species: | N. villosa |
| Binomial name | |
| Nepenthes villosa Hook.f. (1852) | |
| Synonyms | |
| |
Nepenthes villosa/nɪˈpɛnθiːzvɪˈloʊzə/, or thevillose pitcher-plant,[4] is a tropicalpitcher plantendemic toMount Kinabalu and neighbouringMount Tambuyukon in northeasternBorneo. It grows at higher elevations than any other BorneanNepenthes species, occurring at elevations of over 3,200 m (10,500 ft).Nepenthes villosa is characterised by its highly developed and intricateperistome, which distinguishes it from the closely relatedN. edwardsiana andN. macrophylla.[5]
Thespecific epithetvillosa isLatin for "hairy" and refers to the denseindumentum of this species.
Nepenthes villosa wasformally described in 1852 byJoseph Dalton Hooker. The description was published inIcones plantarum and accompanied by an illustration.[6]
The species was first collected in 1858 byHugh Low when he made his second ascent ofMount Kinabalu together withSpenser St. John.[4]
In an issue ofCurtis's Botanical Magazine published in 1858, an illustration of an upper pitcher ofN. veitchii was incorrectly identified asN. villosa by J. D. Hooker's father,William Jackson Hooker.[7][8] That year,N. villosa was also covered inFlore des Serres et des Jardins de l'Europe byLouis van Houtte, in which the same illustration was reproduced along with the incorrect identification.[9]
In 1859,N. villosa was again described and illustrated in J. D. Hooker's treatment of the genus published inThe Transactions of the Linnean Society of London.[note a][10] The illustration and description were reproduced inSpenser St. John'sLife in the Forests of the Far East, published in 1862.[11]
B. H. Danser treatedN. edwardsiana in synonymy withN. villosa in his seminal monograph "The Nepenthaceae of the Netherlands Indies", published in 1928. The work included a revisedLatin diagnosis and botanical description ofN. villosa.[note b][3]
Danser listed four herbarium specimens that he identified as belonging toN. villosa. These include two collected byGeorge Darby Haviland fromMount Kinabalu in 1892. One of these,Haviland 1656/1232, was collected at an elevation of 2,400 m (7,900 ft). It includes male floral material and is deposited at the Herbarium of theSarawak Museum. The second specimen,Haviland 1813/1353, was collected from theMarai Parai plateau at an elevation of 1,650 m (5,410 ft); it likely representsN. edwardsiana. It is also deposited at the Herbarium of the Sarawak Museum. It does not include floral material. G. D. Haviland explored the Mount Kinabalu area with his brother H. A. Haviland between March and April, 1892, and must have collected these specimens during this time.[12][13]
Additionally, Danser lists two specimens collected byJoseph Clemens in 1915. The first,Clemens 10627, was collected on November 13 from Paka Cave to Low's Peak. It includes female floral material. The second,Clemens 10871, was collected at Marai Parai between November 22 and November 23, and does not include floral material. Both specimens are deposited at theBogor Botanical Gardens (formerly the Herbarium of the Buitenzorg Botanic Gardens) inJava.[3]
InLetts Guide to Carnivorous Plants of the World, published in 1992, a specimen of the naturalhybridN. × kinabaluensis (N. rajah ×N. villosa) is labeled asN. villosa.[14]
In 2004, professional horticulturist Robert Sacilotto published a summary of measured tolerances of six highlandNepenthes species, includingN. villosa, based on experiments conducted between 1996 and 2001.[15]
Many of theN. villosa plants in cultivation today originate from a particularly vigoroustissue culture clone introduced by Phill Mann ofAustralia and later sold by theSri Lankan-based plant nursery,Borneo Exotics.[16]
Nepenthes villosa is a weak climber, rarely exceeding 60 cm (24 in) in height,[4] although the stem may grow to 8 m (26 ft) in length and 10 mm (0.4 in) in diameter.Internodes are cylindrical and up to 10 cm (4 in) long.[5]
Leaves arecoriaceous andpetiolate. Thelamina isspathulate to oblong and may be up to 25 cm (10 in) long and 6 cm (2.4 in) wide. The apex of the lamina isemarginate. Thepetiole iscanaliculate, up to 10 cm (3.9 in) long, and bears anamplexicaul sheath. One to three longitudinal veins are present on either side of themidrib.Tendrils may reach 50 cm (20 in) in length.[5]
Lower and upper pitchers are very similar. They areurceolate toovate in shape. The pitchers grow up to 25 cm (10 in) high[4] and 9 cm (3.5 in) wide. A pair of fringed wings (≤15 mm wide) runs down the front of the pitcher, although it may be reduced to ribs in aerial traps. The pitcher mouth isoblique and elongated into a neck at the rear. The glands on the inner surface are overarched and occur at a density of 200 to 1,300 per square cm (30 to 200 per square in).[3] Theperistome is cylindrical in cross section and up to 20 mm (0.8 in) wide. It bears well developed teeth and ribs. The lid oroperculum iscordate and has a pointed apex.[5] It has a pair of prominent lateral veins.[17] An unbranchedspur, ≤ 20 mm (0.8 in) long, is inserted at the base of the lid.[5]
Nepenthes villosa has aracemoseinflorescence. Thepeduncle may be up to 40 cm (16 in) long, while therachis grows to 20 cm (8 in) in length.Pedicels arefiliform-bracteolate and up to 15 mm (0.6 in) long.Sepals are round to elliptic and up to 4 mm (0.2 in) long.[5][18] A study of 490pollen samples taken from two herbarium specimens (J.H.Adam 1124 andJ.H.Adam 1190, collected at an elevation of 1,800–3,400 m (5,900–11,200 ft)) found the mean pollen diameter to be 37.2 μm (SE = 0.2;CV = 6.7%).[19]
The species has a denseindumentum of long, brown hairs that covers all parts of the plant.[5]
Nepenthes villosa isendemic to the upper slopes ofMount Kinabalu and neighbouringMount Tambuyukon inSabah,Borneo.[20] It generally grows at 2,300–3,240 mabove sea level,[20] the highest elevation of all BorneanNepenthes species; onlyN. lamii fromNew Guinea is found at greater elevations.[5][20][21] On Mount Kinabalu,N. villosa is common along theMesilau Trail (between Pondok Magnolia and the meeting point with the old summit trail) and almost all the way up to the Laban Rata rest house;[22] a particularly large population has been reported at around 3047 m.[23] On Mount Tambuyukon, an altitudinal inversion has been noted, wherebyN. villosa is more common at much lower elevations of 1600–1900 m, being replaced byN. rajah towards the summit.[20] The exposed, uppermost slopes of Mount Tambuyukon can become very hot during the day and this might explain the inability ofN. villosa to colonise them.[20] Plants from Mount Tambuyukon generally produce slightly more elongated pitchers.[24]
Nepenthes villosa often grows inmossy forest and sub-alpine forest dominated by species of the generaDacrydium andLeptospermum, particularlyLeptospermum recurvum. It has also been recorded growing among shrubs, grass, and boulders in open areas. Here the soil may become relatively dry, althoughrelative humidity is usually close to 100% as the slopes are often enveloped in clouds. Like manyNepenthes from the Mount Kinabalu area, it is endemic toultramafic soils.[1][4][5]
Although many plants grow along Mount Kinabalu's summit trail and are easily accessible to climbers, all known populations of the species grow withinKinabalu National Park and so their collection is illegal. In 1997,Charles Clarke suggested a revised assessment ofConservation Dependent based on this. Clarke writes thatN. villosa "has a secure future", although he adds that climbers have had a significant impact on populations of the species growing along the summit trail, with the number of plants having declined in recent years.[5] A 2002 study found 1,180 individualN. villosa growing in 11 plots, each measuring 0.01hectares, at elevations of between 2,610 m (8,560 ft) and 2,970 m (9,740 ft) on Mount Kinabalu. This number constituted 94% of the pitcher plants recorded from the plots, the rest beingN. × kinabaluensis.[citation needed]
Nepenthes villosa is most closely related toN. edwardsiana andN. macrophylla. There has been much taxonomic confusion surrounding the status of these threetaxa.
Joseph Dalton Hooker, who described bothN. edwardsiana andN. villosa, noted the similarity between the two species as follows:[10]
This most remarkable plant [N. villosa] resembles that ofedwardsiana in so many respects, especially in the size, form and disposition of the distant lamellae of the mouth, that I am inclined to suspect that it may be produced by young plants of that species, before it arrives at a stage when the pitchers have elongated necks.
Günther Beck von Mannagetta und Lerchenau was the first to treatN. edwardsiana in synonymy withN. villosa when he published his monograph on the genus in 1895.[25]
In his 1908 monograph,John Muirhead Macfarlane wrote the following with regards to the two species: "Examinatione microscopica probatur, illas species distinctas esse".[26] This is probably "based on the old belief that plants, which differ anatomically, can not be forms of the same species".[3]
B. H. Danser united the species "[w]ith some hesitation" in his 1928 monograph "The Nepenthaceae of the Netherlands Indies". He suggested thatN. villosa is a stunted form ofN. edwardsiana from higher elevations, which flowers at a "juvenile stage of development".[3] Danser acknowledged that theindumentum ofN. villosa is more dense than that ofN. edwardsiana, but noted that it "is a difference only of degree".
The two taxa differ considerably in their altitudinal distributions.Nepenthes villosa usually occurs at ultrahighland elevations, 2,300–3,240 m (7,550–10,630 ft),[20] whereasN. edwardsiana is found between 1,500–2,700 m (4,900–8,900 ft).[5] Where their altitudinal distributions overlap, they are still identifiable as distinct species.
Nepenthes macrophylla was originally described in 1987 as asubspecies ofN. edwardsiana byJohannes Marabini.[27] It was later elevated to species status byMatthew Jebb andMartin Cheek.[28] This interpretation was supported byCharles Clarke, who noted thatN. edwardsiana andN. villosa "have more in common" thanN. edwardsiana andN. macrophylla.[5] WhereasN. edwardsiana andN. villosa are restricted to the Kinabalu area,N. macrophylla is only found near the summit ofMount Trus Madi.[5]
Matthew Jebb and Martin Cheek suggest thatN. villosa is related toN. mira, a speciesendemic toPalawan in thePhilippines.[29][30]N. villosa also shows affinities toN. peltata ofMindanao.[31]
Two naturalhybrids involvingN. villosa have been recorded.[20]
Nepenthes × harryana is the natural hybrid betweenN. edwardsiana andN. villosa. Its two parent species are very closely related and soN. × harryana, which is intermediate in form, may be difficult to distinguish from either of them.
It was originally described as a species in 1882 byFrederick William Burbidge.[32]John Muirhead Macfarlane was the first to realise its hybrid origin and described it as such in his monograph of 1908.[26] Danser wrote thatN. × harryana could be a hybrid as Macfarlane suggested, or a form ofN. villosa together withN. edwardsiana.[3]
Nepenthes × harryana can be distinguished fromN. villosa on the basis of its pitcher morphology. The pitchers of the hybrid are more cylindrical than those ofN. villosa, whereas theindumentum is more dense than that ofN. edwardsiana. The hip of the pitcher cup, which is found just below the peristome inN. villosa and in the lower quarter ofN. edwardsiana pitchers, is located around the middle ofN. × harryana pitchers. However,N. villosa plants fromMount Tambuyukon are easier to confuse with this hybrid, as they produce pitchers that may be elongated slightly above the hip.[5]
Nepenthes × harryana is known from a ridge above theUpper Kolopis River and from two locations along the Kinabalu summit trail. SinceN edwardsiana does not grow along the summit trail, it cannot be confused with this hybrid there.[5] Burbidge wrote thatN. edwardsiana,N. × harryana, andN. villosa "are quite distinct in zone of the mountain".[32]
Nepenthes × kinabaluensis is the natural hybrid betweenN. rajah andN. villosa. It was first collected nearKambarangoh on Mount Kinabalu byLilian Gibbs in 1910 and later mentioned byJohn Muirhead Macfarlane as "Nepenthes sp." in 1914.[33] Although Macfarlane did not formally name the plant, he noted that "[a]ll available morphological details suggest that this is a hybrid betweenN. villosa andN. rajah".[34] It was finally described in 1976 byShigeo Kurata asN. × kinabaluensis. The name was published inNepenthes of Mount Kinabalu, but it is anomen nudum, as it had an inadequate description and lacked information on thetype specimen. The name was subsequently republished by Kurata in 1984[35] and byJ. H. Adam andC. C. Wilcock in 1998.[36]
The pitchers ofN. × kinabaluensis may be quite large, but do not compare to those ofN. rajah orN. × alisaputrana (N. burbidgeae ×N. rajah).N. × kinabaluensis can only be found on Mount Kinabalu (hence the name) and nearby Mount Tambuyukon, where the two parent species occursympatrically.[5] More specifically, plants are known from a footpath near Paka Cave and several places along an unestablished route on a south-east ridge, which lies on the west side of theUpper Kolopis River.[33] The only accessible location from which this hybrid is known is the Kinabalu summit trail, betweenLayang-Layang and thehelipad, where it grows at about 2,900 m (9,500 ft) in a clearing dominated byDacrydium gibbsiae andLeptospermum recurvum trees.N. × kinabaluensis has an altitudinal distribution of 2,420 m (7,940 ft) to 3,030 m (9,940 ft).[37] It grows in open areas in cloud forest.
The hybrid is generally intermediate in appearance between its parent species. Raised ribs line the inner edge of the peristome and end with elongated teeth. These are more prominent than those found inN. rajah and smaller than those ofN. villosa. The peristome is coarse and expanded at the margin (but not scalloped like that ofN. rajah), the lidorbiculate orreniform and almost flat. In general, pitchers are larger than those ofN. villosa and the tendril joins the apex about 1–2 cm (0.4–0.8 in) below the leaf tip, a feature which is characteristic ofN. rajah.[38] In older plants, the tendril can be almost woody.N. × kinabaluensis is an indumentum of villous hairs covering the pitchers and leaf margins, which is approximately intermediate between the parents. Lower pitchers have two fringed wings, whereas the upper pitchers usually lack these. The colour of the pitcher varies from yellow to scarlet.N. × kinabaluensis seems to produce upper pitchers more readily than either of its parents. In all respectsN. × kinabaluensis is intermediate between the two parent species and it is easy to distinguish from all otherNepenthes of Borneo. However, it has been confused once before, when the hybrid was misidentified as bothN. rajah andN. villosa[39] inLetts Guide to Carnivorous Plants of the World, published in 1992.[14]
- Ascidia magna, ore lamellis latis disciformibus annularibus remotis instructo.
- Nepenthes Villosa, H. f. (Hook, Ic. Pl. t. 888).
—Ascidia magna turgida late pyriformia coriacea, 5" longa, 3½" lata, alis anticis mediocribus grosse dentatis, ore aperto annulo maximo! lamellis annularibus distantibus disciformibus rigidis, 1" diam., cristatis posticis in spinas rigidas ½" longas, fundum ascidii spectantibus productis, collo elongato erecto, operculo orbiculato intus densissime glanduloso dorso basi longe cornuto. (Tab. LXIX.)
- Hab.—Borneo (Lobb), Kina Balu, alt. 8,000–9,000 feet (Low).
Folia mediocria petiolata, lamina obovato-oblonga v. lanceolata, nervis longitudinalibus utrinque 2-3, vagina caulem fere totum amplectente;ascidia rosularum ignota;ascidia inferiora magna, breviter ovata, costis 2 ad os alatis fimbriatis; peristomio operculum versus in collum elongato 6-12 mm lato, costis altis 3-12 mm distantibus, dentibus 1-3 x longioribus quam latis; operculo rotundato-cordato v. paulum reniformi, facie inferiore plano;ascidia superiora magna, parte inferiore ventricosa os versus cylindrica, costis 2 prominentibus; peristomio operculum versus in collum elevato, 12-22 mm lato, costis altis 3-12 mm distantibus, dentibus 1-3 x longioribus quam latis; operculo rotundato-ovato v. paulum reniformi, facie inferiore plano;inflorescentia racemus pedicellis inferioribus 12 mm longis omnibus 1-floris;indumentum villosum.
