Calamus tetradactylus
| Calamus (KAL-ah-muhs) tetradactylus (teh-trah-dahk-TIHL-uhs) | |||||||
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 Guandong, China. | |||||||
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Contents
Habitat and Distribution
China (Yunnan, exact location unclear, and South-east China), Thailand (East and South-east),
C. tetradactylus is frequently found in areas north to 23°30'N, including southern parts of Guangdong, Guangxi and Fujian as well as in Hainan Island and the center of distribution is in Huilai, Huidong, Zhuhai, Yangjiang, Gaozhou and Qingzhou. The species is found over low hills and terraces with an altitude below 600 m and scarcely above on Hainan Island [1]. The south-western areas of Hainan Island are rather dry and hot, with an annual rainfall of 1000 mm and dry season of 5-7 months. In the valley, the plants of this species are naturally abundant, with an annual mean temperature of 21-25°C annual sunshine of 1900-2400 hrs, annual precipitation of 1000-2300 mm. The distribution is uneven in areas with dry season from November to February, occasionally with spring rains in the areas. The co-efficient of water to temperature is 1.5-2.5 and the annual mean relative humidity above 79%. (See external link - Growth and phenology of Calamus tetradactylus)
Description
Calamus tetradactylus is a clustering, slender, dioecious rattan, climbing to 30 m or more, distributed in tropical and sub-tropical China. The species is one of the most important commercial rattans because of its superior quality and high economic value. With characteristics of fast growth, rich sprouting habit and strong adaptation, C. tetradactylus is very suitable for plantations. On the basis of continuous experiment and cultivation practices in several sites, the techniques to establish plantations of C. tetradactylus have been well developed. The paper mainly deals with the biological and ecological characteristics of C. tetradactylus.
Slender clustering rattan. Stems climbing to 10 m or more long, without sheaths 0.3–1 cm in diam., with sheaths 0.7–1.8 cm in diam., internodes up to 18 cm long. Leaf ecirrate; sheaths mid green, tending to dry pale, with scattered yellow brown narrow triangular spines 0.2–1.5 cm long, with dark tips, armature variable in abundance; ocrea inconspicuous; knee conspicuous, generally unarmed; flagellum to 1.8 m long; petiole 3–10 cm long; rachis 20–60 cm long; leaflets broadly lanceolate, up to about 10 on each side of the rachis, grouped in pairs except at the apex where a group of 4 in all, and at the very base where occasionally solitary, leaflet grouping sometimes irregular, largest leaflets 11–28 x 2–6.5 cm, the margins usually bristly. Inflorescences male and female superficially similar, the male branched to 3 orders, the female to 2 orders, with up to 4 rather distant diffusely branched partial inflorescences; male rachillae to 12 x 1.5 mm; female rachillae 15–50 x 2 mm. Mature fruit spherical, briefly beaked, about 0.9 cm in diam., covered in about 15 vertical rows of pale straw-coloured scales with narrow darker margins. Seed rounded, flattened on one side, about 0.5 x 0.4 cm; endosperm shallowly ruminate. Editing by edric.
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When Conrard (in Gagnepain & Conrard 1937) cited only Bon 3549 in naming C. tetradactylus var. bonianus he implicitly made this the lectotype. Although Conrard attributed the variety to Beccari it is more correctly cited as shown, since Beccari published the name at another rank. Beccari (1910) diagnosed C. cambojensis on the basis of its 'slender and flaccid spadix with narrower, longer and more closely sheathing spathes' and C. bonianus by its 'denser partial inflorescences with more spikelets and these with more flowers' and also by the sessile involucrophore and possibly smaller fruit (although these latter he had only seen immature). He mentioned that C. bonianus may well be only a local form of C. tetradactylus. Extensive new material has allowed a reassessment of the various forms. Calamus bonianus is certainly synonymous with C. tetradactylus. Calamus cambojensis is perhaps more distinctive since material from Cambodia, Kontum Province (Vietnam) and southernmost Laos shows inflorescences where (with the slight exception of Evans, T 59) all primary branches are well exserted from their bracts and so all primary bracts, including the first, are tightly sheathing, whereas the material from elsewhere in Vietnam and China shows one or more of the more proximal primary bracts inflated (always including the most basal) because their corresponding primary branches are inserted within them. However, both types of inflorescence can be seen in the material from Sisaket Province (Thailand) and in view of the obvious variation in the expression of this character (perhaps related to environmental factors governing the exact rate of extension of the inflorescence), together with the great number of other details which are similar between plants from these two areas, we prefer to place all of them in a single, variable species. There may be an argument for recognising two subspecies. However, before doing so it is important to note that variation occurs in several other characteristics, especially around the Annamite mountain chain south of about 18'N. The following examples suggest that further taxa may need to be named in this economically important group once more material and field observations have been collected in this region: 1) plants from one locality in Bolikhamxay Province (Laos) have unusually small leaflets with smooth margins and a strangely 'pinched', acuminate tip, as well as pronounced orangey scale margins on the dry fruit (Oulathong 207, 208 and 209). 2) some plants from Champassak Province (Laos) are particularly robust with broad leaflets drying green and long partial inflorescences (up to 35 or even 40 cm) (e.g. Klackenberg, J. 1090 and 1327, Khamphone 410), whilst others (e.g. Evans, T 59) are more delicate and dry bright yellow. 3) the material from South Annam and Cochinchina (Vietnam) has a waxy coating on the abaxial surface of the leaflets that is thick, floccose (when viewed under 30x magnification) and whitish, almost sufficient to be described as whitish indumentum, and the involucrophore is noticeably pedicelliform (e.g. in Poilane 21614, 21718, 22271 and 23814). 4) some plants bear a curious comb of flexible spines at the sheath mouth, even though the rest of the sheath is sparsely armed (e.g. Averyanov, L. 1525). The involucre on the male plant varies from specimen to specimen between almost discoid and quite deeply cupular, and the rachilla axis of the male plant also varies in thickness. There is a wide range of leaflet sizes, even in Tonkin and south- east China. The longest leaflet on a leaf ranges from 11 to 31 cm in the specimens seen, with most values in the range 14 - 26 cm. Except for the Central Lao specimens all have bristly margins and most have the leaflet surfaces naked, but occasional bristles occur on the middle vein on plants throughout the species' range. The fact that some specimens dry yellow may not be significant - there are two fully fertile and apparently identical sheets of Clemens, J. & M. S. 3100 in BM and of these one has dried uniformly bright yellow, the other uniformly mid-green. (J. Dransfield, A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina. 2002)/Palmweb. |
Culture
Cold Hardiness Zone: 10a
Comments and Curiosities
Uses: The cane is of high quality and is probably important in trade, especially in Vietnam. Vu Van Dung & Le Huy Guang (1996) report that a species to which they give this name has been cultivated by smallholders around Hanoi for over 100 years and the practice is now spreading. This appears to be one of the oldest rattan cultivation systems known.
Conservation: This widespread, common and widely cultivated species is unlikely to be under serious threat. If smaller localised taxa are recognised some of these may be under greater threat.
- IMAGE GALLERY
Guandong, China. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Guandong, China. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
Guandong, China.
External Links
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- Growth and phenology of Calamus tetradactylus Growth and phenology of Calamus tetradactylus Institute of Botany of Guangdong Province
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
J. Dransfield, A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina. 2002
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.
