Caryota (PROSEA)
Introduction |
Caryota L.
- Protologue: Sp. pl. 2: 1189 (1753); Gen. pl., ed. 5: 497 (1754).
- Family: Palmae
- Chromosome number: x= 14, 16, 17; C. cumingii: 2n= 17, C. mitis: 2n= 28, 32, 34, C. urensL.: 2n= 32
Vernacular names
- Fishtail palm (En)
- Indonesia: nibung, sarai
- Malaysia: rabok, tukas
- Philippines: pugahan (Filipino), anibong (Tagalog).
- Burma (Myanmar): minbaw
- Thailand: tao rang
- Vietnam: dùng dình, móc.
Origin and geographic distribution
Caryota comprises about 12 species occurring from Sri Lanka and India to Indo-China, southern China, Burma (Myanmar), Thailand, throughout the Malesian region towards the Solomon Islands and northern Australia.
Uses
Caryota stems yield an inferior timber sometimes used for construction purposes such as planking, rafters, roofing, partitioning and fencing. In Papua New Guinea it is commonly used for flooring and for making spears.
Most species are multipurpose palms. Several are commonly planted for ornamental purposes. The trunk yields starch (sago). In Sarawak the sago of C. no is favoured by the native Punan for its high yield and sweet flavour. The inflorescences, especially those of C. rumphiana, are tapped to produce sugar or palm wine. The palm cabbage (apical meristem) and palm heart are edible when cooked. The fruits and seeds are edible but the mesocarp contains needle-like crystals that cause irritation. The seeds may be chewed as a substitute for betel nut (Areca catechu L.). The leaf sheath fibre ("kittul") of the larger species are used to caulk boats, make rope, brushes and brooms, and the finer fibres for tinder and to make fishing lines or sewing thread. In the Philippines the leaf sheath is sometimes split to weave baskets.
Production and international trade
The use of Caryota wood and of the other products is fair, but on a local scale only.
Properties
Cortex black with white streaks and narrow; central cylinder delimited by a wide peripheral zone of congested vascular bundles; central vascular bundles diffuse, each with a fibrous phloem sheath, xylem sheathed by parenchyma, metaxylem with 2 wide vessels, phloem undivided; ground parenchyma cells secondarily expanded in old stems, becoming somewhat lobed and enclosing wide air spaces.
The wood of C. rumphiana is the most durable palmwood in the Moluccas. The best quality wood is obtained when harvested just before flowering. This may be partly because less starch is stored at this time in the stem.
The average fibre length of C. cumingii is 1.5-2.2 mm.
Botany
- Unarmed, monoecious, hapaxanthic, solitary or clustered, small to large palms up to 40 m tall; pole straight, unbranched, up to 70 cm in diameter, obscured at first by persistent fibrous leaf bases and sheaths, conspicuously ringed with narrow leaf scars, internodes elongated.
- Leaves bipinnate (pinnate in juveniles), induplicate with a terminal leaflet; sheath triangular, disintegrating into strong black fibres, densely hairy; petiole channelled above; leaflets numerous, obliquely wedge-shaped, upper margin irregularly toothed.
- Inflorescence axillary, solitary, pendulous, branched to 1 order or rarely unbranched, bisexual; prophyll tubular; peduncular bracts up to 8, large; distal portion of rachis bearing spirally arranged, protandrous triads of 2 male flowers and 1 female flower.
- Flowers with 3 sepals and 3 petals. Male flower with free petals; stamens 6-many, filaments short, sometimes connate at base. Female flower globose; petals connate up to halfway; ovary superior, 3-locular with a single ovule per cell, stigma 3-lobed.
- Fruit a globose, smooth drupe, 1-2-seeded, orange or red to dark red or purple; mesocarp fleshy, with irritant, needle-like crystals.
- Seed with ruminate endosperm.
- Seedling with epigeal, remote-tubular germination; eophyll bifid with rhombic, divergent, praemorse segments.
Vesicular-arbuscular mycorrhizae have been found in C. urens. When mature, the tree produces an inflorescence from the uppermost leaf axil and in a period of several years it flowers from subsequent downward axils. It dies after the last inflorescence has fruited. C. urens develops according to Holttum's architectural tree model, characterized by a single apical meristem which differentiates completely into an inflorescence after initial vegetative development. In Java C. no was observed to start flowering after 16 years, suggesting a life cycle of about 20 years. The fruits are eaten by monkeys and other mammals, e.g. civet cats and bats, as well as by large birds such as hornbills and cassowaries thus dispersing the seeds.
Caryota is in need of a taxonomic revision, as the identity of many species and forms is unclear. It is closely related to Arenga and Wallichia with which it forms the tribe Caryoteae of the subfamily Arecoideae. Caryota is easily recognized by its double pinnate leaves, bisexual inflorescence and seeds with ruminate endosperm. C. urens is a tall palm from Sri Lanka, India and Burma (Myanmar) that was probably introduced to Vietnam and Thailand, and which has been used for construction and for tapping sugar and palm wine.
Ecology
Caryota is found in primary and secondary, lowland to montane forest, up to 2000 m altitude. It occurs in monsoon and perhumid climates. In Peninsular Malaysia C. mitis is characteristic of secondary forest and of forest on limestone.
Silviculture
Caryota can be propagated by seed, which remains viable for 4-6 weeks. Seeds of C. urens germinate in 18-30 days but those of C. cumingii do not start germinating until 10 months after soaking in water for several days. The daily yield per tree of sap for wine and sugar from C. urens is 20-27 l; its trunk yields 100-150 kg of starch. The harvest of Caryota for sago and other purposes is mainly from wild and semi-wild populations.
Genetic resources and breeding
C. no has been identified as a vulnerable species by the International Union for the Conservation of Nature (IUCN).
Prospects
It is unlikely that the use of Caryota wood will increase in the near future, but it has potential as an ornamental. Furthermore, its products for human consumption (sap, starch, palm cabbage, palm heart) make it an interesting multipurpose agroforestry species, in particular C. mitis.
Literature
70, 86, 150, 163, 236, 278, 285, 323, 324, 338, 402, 436, 499, 500, 563, 720, 733, 873, 978, 1051, 1059, 1100, 1110, 1176, 1210.