Nephelium ramboutan-ake

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Nephelium ramboutan-ake


Tree, mostly less than 10 m, sometimes up to 36 m high, dbh up to 60 cm, with up to 2.40 m high buttresses. Leaves (1-foliolate or) 1-7-jugate; Inflorescences axillary, partly together pseudoterminal. Sepals slightly or up to halfway connate, 1-2.75 mm long. Petals absent. Stamens 5-8. Ovary 2- (rarely 3-)celled. Fruits ellipsoid to subglobular, 4-6.5 by 2.5-5 cm, glabrous, coarsely spiny, spines up to 1.5 cm long, bulbous-based and often confluent at the base, or sometimes knobby, knobs short tongue-shaped;


Asia-Tropical: Assam (Assam present); Borneo present; Jawa (Jawa present); Malaya (Peninsular Malaysia present); Maluku (Maluku present); Philippines (Philippines present); Sumatera (Sumatera present), Burma present
Assam, Burma, and Malesia: Sumatra, Malay Peninsula, Borneo, Java (doubtful), Philippines, Moluccas (indigenous?).


Cultivated as a fruit tree; the timber is also used. See .


1. This species is rather a variable one, as already noted by Blume in his specific epithet mutabile. 'Typical' material, as it is commonly found in Malaya, Sumatra, Java, and Borneo, is characterized by thin-pergamentaceous leaflets which are commonly rolled up in the herbarium, unlike most other species of Nephelium; they are reddish brown above and glaucous beneath; the midrib is slightly raised and slender above, the nerves are rather steeply ascending, and distinctly curved; domatia are common; the reticulation is fairly lax and usually visible above.
The most distinct form is restricted to Borneo and is characterized by 1-3-jugate leaves, relatively large, thin-coriaceous leaflets which are glabrous above and often so beneath, lack domatia, have a midrib that is hardly raised to slightly sunken and more rounded above, and dense, steeply ascending, and; nearly straight nerves. The veins and veinlets are clearly different, the former being mostly rather densely scalariform and raised on both sides, the latter more vaguely laxly reticulate. This form resemb es N. lappaceum var. xanthioides but differs in its leaflets, which are nearly glabrous beneath, at least on the midrib, by the midrib itself, which is at least at the base slightly raised above, and the mainly axillary inflorescences and especially infructescences. Nephelium lappaceum var. xanthioides has the midrib densely hairy beneath, slightly sunken above at the base, and has terminal inflorescences and infructescences. The Philippine material lies more or less in between the typical form and the Bornean form.
Nephelium intermedium represents a morphologically extreme population from the Philippines, mainly characterized by the relatively long and slender fruit appendages. The only character given by Radlkofer which does not fit with N. ram-boutan ake is the hairiness of the disk. This could not be checked in the very fragmentary type material left; otherwise comparable Philippine collections have a glabrous disk. However, one of the syntypes of N. intermedium, Warburg 13109, is Dimocarpus longan Lour, subsp. malesianus Leenh. and this flowering specimen has a hairy disk, so this may be the source of the mistake. Apparently, with the name intermedium Radlkofer intended to express that this species was in between N. rambohtan-ake and N. lappaceum L. var. pallens (Hiern) Leenh., in both general appearance as well as in some characters.
The fruits of Kostermans 13333 (E Kalimantan, Sangkulirang Dist., Mt Medadem, N of Sang-kuliranj;) are quite unusual: the appendages are very dense, thick knobby, c. 5 mm high, and lack an apical part; they resemble small fruit heads of a Pandanus.
2. It is difficult to say whether the rather few and mostly old collections from Java were gathered from wild trees, even though at least West Java lies within the natural area of the species. The occurrence in the Moluccas does not seem natural: it lies distinctly outside the area of the species, and the collections seen by me represent the typical western form, not the Philippine one, and at least the collections made by Labillardière in the early 1790's were derived from cultivated trees, which were said to have been imported by Chinese.
3. Nephelium ramboutan-ake may easily be confused with Dimocarpus longan Lour. var. ech-inatus Leenh. because of a sometimes strong resemblance in the leaves; the fruits are nearly identical. In principle, both species are clearly different in the kind of hairs they bear; the former has solitary hairs, the latter stellate hair tufts. However, both may be nearly glabrous, Nephelium ramboutan-ake then having only very sparse minute appressed hairs on the lower leaf side, Dimocarpus longan var. echinatus having a few minute hair tufts on the lower side of the nerves but so minute that even at x 10 magnification they are hardly visible. A good additional character is that the bark of the twigs is usually white in Dimocarpus longan, brownish in Nephelium ramboutan-ake.
4. The fruits of the present species may resemble those of N. macrophyllum; for differences between the two species, see there.
5. Nephelium lappaceum var. pallens may resemble N. ramboutan-ake. Good characters in which the former differs from the latter are among others the midrib which is flat to sunken above instead of mostly raised, veins and veinlets that are slightly raised above instead of inconspicuous, the reticulation is rather dense, not lax.


Valeton 1902 – In: Bull. Inst. Bot. Buitenzorg: 7
Radlk. 1933 – In: Engl., Pflanzenr. 98: 963
Ridley 1922 – In: Fl. Malay Penins.: 501
Hiern 1875 – In: Hook. f., Fl. Br. India 1: 686
Backer 1911: Schoolfl. Java: 266
Radlk. 1933 – In: Engl., Pflanzenr. 98: 967
Backer & Bakh. f. 1965 – In: Fl. Java: 138
Ridley 1930: Dispersal: 344
Koord. & Valeton 1903 – In: Bijdr. Booms. Java: 192
Ridley 1900 – In: J. Str. Br. Roy. As. Soc.: 66
Miq. 1859 – In: Fl. Ind. Bat.: 555
H.S. Yong 1981: Magnificent Plants: 128
Meijer 1968 – In: Bot. Bull. Herb. Sandakan: pl. between p. 111 and 112 (seedling)
Corner 1940: Wayside Trees: 593: f. 215
Ceron 1892: Cat. Pl. Herb. Manila: 54
Merr. 1923 – In: Enum. Philipp. Flow. Pl.: 505