Nepenthes naga Akhriadi, Hernawati, Primaldhi & M. Hambali

Nepenthes naga is a tropical pitcher plant endemic to the Barisan Mountains of Sumatra. It is characterised by a forked sub-apical appendage on the underside of the lid and an undulate lid margin.^[2] The specific epithet naga is the Indonesian word for "dragon" and refers to the distinctive lid appendage of this species as well as the large size of its pitchers. The name also references local folklore, which tells of dragons occurring in this species's habitat in the past.^[2]

Botanical history

Nepenthes naga was first collected by Indonesian hobbyists between March and July 2007 as part of an expedition by Division Nepenthes Indonesia. The herbarium specimen A.Primaldhi & M.Hambali DivNep052 is the designated holotype, and is deposited at the herbarium of Andalas University (ANDA), near Padang, West Sumatra. An isotype is deposited at Herbarium Bogoriense (BO), the herbarium of the Bogor Botanical Gardens. The specimen was collected by Alfindra Primaldhi and Muhammad Hambali on July 27, 2007, at an elevation of between 1500 and 2000 m.^[2]

The species was formally described^{[note a]} by Pitra Akhriadi, Hernawati, Alfindra Primaldhi and Muhammad Hambali in a 2009 issue of the botanical journal Reinwardtia.^[2] The description includes a line drawing of the type specimen by Hernawati, showing lower and upper pitchers as well as a female inflorescence.^[2]

Description

Nepenthes naga is a climbing plant growing to a height of around 5 m. The stem is up to 1 cm in diameter. Internodes are circular to rhomboid in cross section and up to 14.8 cm long.^[2]

A rosette pitcher with a greatly expanded peristome

The leaves are sessile. The lamina or leaf blade is spathulate to oblong in shape and coriaceous (leathery) in texture. The leaves of rosettes are up to 27 cm long by 7.8 cm wide, whereas those of the climbing stem are up to 16 cm long by 6 cm wide. The base of the lamina clasps the stem by one half to three quarters of its circumference. The midrib is concave on the upper surface and triangular on the lower surface. Three longitudinal veins are present on either side of the midrib, although they are only distinct on the underside. Pinnate veins are indistinct. The lamina has an entire margin and a slightly emarginate to rotundate apex. In rosettes, the tendrils are up to 41 cm long and have a peltate attachment, joining the lamina around 0.3 cm before its apex. Tendrils produced on the climbing stem are inserted apically and are up to 28 cm long.^[2]

Rosette and lower pitchers are ovoid in the lower part, becoming cylindrical above. They are large, growing to 33.5 cm high by 6.8 cm wide. A pair of fringed wings (≤0.5 cm wide) runs down the ventral surface of the pitcher cup. Fringe elements are up to 1.9 cm long. The pitcher mouth is ovate and elongated into a short neck at the rear. The greatly expanded peristome may be up to 5.8 cm wide at the sides. Its inner margin is lined with distinct teeth, with those of the neck reaching 0.4 cm in length. The pitcher lid or operculum is ovate and has an unusual undulate margin. It measures up to 8.5 cm in length by 7.2 cm in width and has a cordate base. Four to five pairs of veins are visible on the upper surface of the lid. The lid bears two prominent appendages on its lower surface. The first is a hooked basal crest up to 0.7 cm long. The second is a triangular, dichotomous appendage present near the apex. This unique feature measures up to 1.4 cm in length and bears large nectar glands (0.5 to 1 mm in diameter). Smaller glands (0.1 to 0.5 mm in diameter) are concentrated along the midrib. An unbranched spur (≤2.8 cm long) is inserted near the base of the lid.^[2]

The underside of the lid of N. naga, showing a prominent hook-shaped basal crest and the forked sub-apical appendage for which it is named

Upper pitchers are infundibular in the lowermost part, becoming ovoid and then cylindrical above. They may be up to 24.3 cm high by 4.5 cm wide. A pair of ribs is present instead of wings. The mouth is ovate and has a neck. The peristome is much narrower than that found in lower pitchers, measuring only up to 1 cm in width. Its teeth, although distinct, are also much shorter, with those of the neck reaching 1.3 mm. The fringed lid is ovate, has a cordate base, and measures up to 6.1 cm in length by 5.5 cm in width. Three to four pairs of veins are visible on the upper surface of the lid. As in their terrestrial counterparts, the lid of aerial pitchers bears two appendages on its underside. The hook-shaped basal crest is up to 0.3 cm long, while the forked sub-apical appendage reaches 1.5 cm. The latter bears large nectar glands (0.5 to 1 mm in diameter), with smaller ones (0.1 to 0.2 mm in diameter) concentrated along the lid midrib's lower surface. The spur (≤1.4 cm long) is flattened and has a bifurcate apex.^[2]

Only the female inflorescence of N. naga is known. It is a raceme measuring up to 14.5 cm in length, of which the peduncle makes up 7 cm and the rachis 7.5 cm. Partial peduncles are one- or two-flowered. Their unbranched basal portion is up to 0.5 cm long, while the branches reach 0.9 cm. Bracteoles are linear and up to 1.2 cm long. Tepals measure up to 0.5 cm. Fruits are up to 1 cm long by 0.4 cm wide.^[2]

Nepenthes naga lacks a conspicuous indumentum; most parts of the plant are glabrous.^[2]

Ecology

Nepenthes naga is known only from a small population in the Barisan Mountains of North Sumatra. It grows epiphytically in mossy montane forest and has an altitudinal distribution of 1500–2000 m above sea level.^[2][3] The vegetation in this habitat is dominated by Fagaceae and Gleicheniaceae, as well as various montane shrubs.^[2]

Nepenthes naga occurs in an unprotected area. Plantations of the Pará rubber tree (Hevea brasiliensis) at the foot of the hill inhabited by N. naga pose a threat to this species. Population decline is also attributed to plant collectors, who have removed a number of plants and collect seeds in such numbers that few are left to germinate naturally.^[2]

The species has no known natural hybrids.^[4]

Related species

An upper pitcher of N. naga bearing a highly developed filiform appendage and frilled lid, which distinguish this species from its closest relatives in the genus

In their description of N. naga, the authors compared it to the Sumatran endemics N. ovata and N. spathulata, contending that it can be distinguished from these species on the basis of its dichotomous lid appendage and frilled lid.^[2] Nepenthes naga is nonetheless very similar to these species and to N. bongso, and may prove to be an aberrant form of one of them.^[4] Populations of N. bongso exhibiting a similarly branching lid appendage have been discovered and "[m]ost authorities believe that [N. naga] falls within the range of variation of N. bongso".^[3]

Notes

References

Wikimedia Commons has media related to Nepenthes naga.

Nepenthes naga adalah tanaman kantong semar endemik Bukit Barisan, Sumatra. Bentuk unik yang membedakan tanaman ini adalah rupanya yang mirip badan botol dan organ yang berbentuk seperti lidah ular yang keluar dari bagian bawah penutup kantongnya.^[1] Nama naga diambil dari bahasa Indonesia yang merujuk pada bentuk penutup kantong dan badan eksternalnya serta ukurannya yang besar. Nama ini juga merujuk pada cerita rakyat di Bukit Barisan yang disebut-sebut sebagai habitat naga pada masa lalu.^[1]

Referensi

Nepenthes naga Akhriadi, Hernawati, Primaldhi & M.Hambali, 2009 è una pianta carnivora della famiglia Nepenthaceae^[2], endemica dei Monti Barisan, a Sumatra, dove cresce a 1500–2000 m.

Conservazione

La Lista rossa IUCN classifica Nepenthes naga come specie vulnerabile.^[1]

Note

Bibliografia

• Akhriadi, P., Hernawati, A. Primaldhi & M. Hambali 2009. Nepenthes naga, a new species of Nepenthaceae from Bukit Barisan of Sumatra. Archived 2016-03-04 at the Wayback Machine. Reinwardtia 12(5): 339–342.
• McPherson, S.R. 2009. Pitcher Plants of the Old World. 2 volumes. Redfern Natural History Productions, Poole.

龙猪笼草（学名：Nepenthes naga）是婆罗洲巴里桑山脉特有的热带食虫植物。其特点为笼盖下表面末端附近具有分叉的附属物，且笼盖的边缘呈波浪状。^[1]种加词“naga”来源于印尼文，意为“龙”，指该物种独特的笼盖附属物，以及巨大的捕虫笼。这个名字也来源于当地的民间传说，其记叙道该物种的原生地曾有龙出没。^[1]

植物学史

2007年3月至7月，由印度尼西亚猪笼草爱好者首次采集到龙猪笼草，该发现为印度尼西亚猪笼草属植物考察分队的一部分考察结果。编号为“A.Primaldhi & M.Hambali DivNep052”的标本被指定为模式标本，其存放于西苏门答腊省巴东附近的安达拉斯大学植物标本馆（ANDA）。在茂物植物园植物标本馆（BO）还存放着一个等模标本。2007年7月27日，Alfindra Primaldhi和穆罕默德·汉巴里（Muhammad Hambali）在海拔1500米至2000米的地区采集到了这些标本。^[1]

2009年，Pitra Akhriadi、Hernawati、Alfindra Primaldhi和穆罕默德·汉巴里在植物学杂志《分类生物学、植物社会学、植物生态学杂志》（Reinwardtia）上发表了关于该物种的正式描述^{[注 1]}。^[1]该描述包括一幅由Hernawati创作的模式标本线条画，其展示了下位笼、上位笼和雌性花序的形态。^[1]

形态特征

龙猪笼草的下位笼，示其发达的唇

龙猪笼草为藤本植物，其可攀至5米的高处。其茎直径可达1厘米，呈圆形至菱形。节间距可达14.8厘米。

龙猪笼草的叶片革质，无柄，呈匙形至长圆形。莲座状植株的叶片可长达27厘米，宽至7.8厘米；攀援茎的叶片可长达16厘米，宽至6厘米。叶基包住茎部周长的二分之一至三分之一。叶片上表面的中脉处凹陷，下表面呈三角状凸起。中脉的两侧各有3条纵脉，但仅在叶片的下半部较为明显。羽状脉不明显。叶片全缘，叶尖微缺至圆。莲座状植株的笼蔓可长达41厘米，在距叶尖0.3厘米处与之衔接，呈盾形。攀援茎的笼蔓可长达28厘米，与叶尖连接。^[1]

龙猪笼草笼盖的下表面，示其基部钩状的附属物和末端附近叉状的附属物

龙猪笼草下位笼的下半部为卵形，上半部为圆柱形。其可高达33.5厘米，宽至6.8厘米。腹面具一对可宽达0.5厘米的笼翼。翼须可长达1.9厘米。笼口为卵形，基部拉长成短唇颈。唇的两侧可宽达5.8厘米。唇内缘有明显的唇齿，唇颈处的唇齿可长达0.4厘米。笼盖呈卵形，边缘呈特殊的波浪状。其可长达8.5厘米，宽至7.2厘米，基部呈心形。笼盖的上表面具有4至5条可见的叶脉，下表面具有两个突出的附属物。第一个位于笼盖基部，呈钩状，可长达0.7厘米。第二个位于笼盖末端附近，为三角形或二岐，这个独特的附属物可长达1.4厘米，并具有大型的蜜腺，其直径为0.5至1毫米。笼盖下表面的中线处密布大量小蜜腺，其直径为0.1至0.5毫米。在笼盖基部后方具有一根可长达2.8厘米的笼蔓尾。^[1]

龙猪笼草上位笼的下部为漏斗形，中部为卵形，上部为圆柱形。其可高达24.3厘米，可宽至4.5厘米。笼翼缩小为一对隆起。唇较下位笼窄，宽仅可达1厘米。唇齿虽然明显，但大大缩短，唇颈处也仅可达1.3毫米。笼盖为椭圆形，基部为心形，可长达6.1厘米，宽至5.5厘米。中脉的两侧可见3至4条纵脉。与下位笼一样，上位笼的笼盖也具有两个附属物。钩状附属物可长达0.3厘米，叉状附属物可长达1.5厘米。叉状附属物上覆盖着大型的蜜腺，其直径为0.5至1毫米，而笼盖下表面的中线处聚集着大量小蜜腺，其直径为0.1至0.2毫米。笼蔓尾扁平，末端二叉。^[1]

仅已知雌性龙猪笼草的花序结构。其为总状花序，可长达14.5厘米，其中总花梗可长达7厘米，花序轴可长达7.5厘米。每个花梗带一朵或两朵花。分支花梗的基部可长达0.5厘米，分叉处可长达0.9厘米。苞片为丝状，可长达1.2厘米。花被片可长达0.5厘米。果荚可长达1厘米，宽至0.4厘米。^[1]

龙猪笼草无明显的毛被；植株的大部分无毛。^[1]

生态关系

龙猪笼草的上位笼，示其发达的丝状附属物和波浪状的笼盖，这两者即是与其他猪笼草属植物相区别的特征

龙猪笼草仅少量存在于北苏门答腊省的巴里桑山脉。其作为附生植物生活于海拔1500米至2000米的苔藓森林中。^[1][2]其原生地的植被主要由壳斗科（Fagaceae）和里白科（Gleicheniaceae）植物及各种山地灌木组成。^[1]

龙猪笼草存在的地区未受到保护。在龙猪笼草所处的山脚下人工种植了大片的橡胶树（Hevea brasiliensis），这对其生存构成了威胁。但是植物收藏者的过度采集也是导致龙猪笼草种群数量下降的一方面原因。过多的采集植株和种子，自然会使得新生植株数量的减少。^[1]

尚未发现龙猪笼草的自然杂交种。^[3]

相关物种

在龙猪笼草的描述中，作者将其与苏门答腊特有的卵形猪笼草（N. ovata）和匙叶猪笼草（N. spathulata）进行了对比，并指出可以基于二岐的附属物和边缘波浪状的笼盖将龙猪笼草与它们区分开来。^[1]此外，龙猪笼草也与其他许多猪笼草比较相似，如邦苏猪笼草（N. bongso），龙猪笼草很可能会被证明是其中一个物种的特殊变型。^[3]已发现了存在类似分叉笼盖附属物的邦苏猪笼草种群，同时“也可相信龙猪笼草的分布范围包含在邦苏猪笼草的分布范围内”。^[2]

注释

参考文献

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