Borassus heineanus
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Contents
Habitat and Distribution
Borassus heineanus is found in New Guinea. Endemic to New Guinea.
Description
Stem to 25 m tall, stem diameter unknown. Leaves 20 – 28 in the crown; petiole and sheath 150 – 300 cm long; petiole 3.1 – 5.2 cm wide at midpoint, green with very sharp black margins, but no spines; costa 130 – 150 cm long; adaxial hastula conspicuous, to 1.2 cm, abaxial hastula absent; lamina radius to 180 cm maximum; leaflets 50 – 90, 3.9 – 7.1 cm wide, apices bifid and cuspidate, shortest leaflet 110 – 130 cm long, leaf divided to 76 – 92 cm; commissural veins 3 – 6 per cm, leaf anatomy dorsiventral. Staminate inflorescences branched to one order, upper subtending branches terminating in 1 rachilla; rachillae brown and catkin-like, ± 70 cm long, 2.7 – 4.3 cm diameter; rachilla bracts forming pits containing a cincinnus of 6 – 12 flowers. Pistillate inflorescences spicate; flowerbearing portion 37 – 49 cm long with 7 – 22 flowers arranged spirally. Staminate flowers exserted from pits individually, 0.4 – 1 cm long, bracteoles 1 × 1 cm; calyx 0.3 × 0.8 cm, shallowly to deeply divided into three sepals, petal lobes 0.2 × 0.1 cm; stamens 6 with very short filaments, 0.11 × 0.15 cm, anthers 0.18 × 0.06 cm; pistillode distinct, 0.2 – 0.5 × 0.02 cm. Pollen monosulcate, elliptical, 51 – 70 mm long, aperture 41 – 63 mm long, polar axis 37 – 57 mm long; tectum perforate, sparsely covered with supratectal gemmae. Pistillate flowers 2.5 × 2 cm; bracteoles large, 1.5 cm diam., sepals 1.5 × 2 cm, petals 1.0 × 1.5 cm. Fruits large, 12 – 15 × 8 – 10 cm, ovoid with a slightly pointed apex, greenish black; pyrenes 1 – 3, 9.2 – 10.5 cm × 4.8 – 7.0 cm × 4.0 – 4.5 cm; endocarp sometimes with flanges that penetrate the seed. (R.P. Bayton. 2007)/Palmweb. Editing by edric.
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Borassus heineanus is by far the most distinctive species in the genus and this led Beccari (1924) to speculate that it should be transferred into Borassodendron. Both B. heineanus and Borassodendron occur in humid rain forest, generally an atypical habitat for Borassus. Unlike all other Borassus species, the petiole is always unarmed, the leaves have a dorsiventral leaf anatomy and cuspidate leaflet apices, the staminate inflorescence branches to one order only and the staminate flowers have a large pistillode. However, the pollen is very similar to that found in the other Borassus species; it has a sulcate aperture that is almost the length of the grain and a perforate tectum with sparse supratectal gemmae. In contrast, the pollen of Borassodendron has a porate aperture and no gemmae (Ferguson et al. 1986). Preliminary results from the molecular study confirm the monophyly of Borassus in its current circumscription (including B. heineanus) and suggest that Borassodendron is sister to Borassus (Bayton 2005). The pyrenes of Borassus heineanus are rather unusual for the genus. In most Borassus species, pyrene length and breadth are similar or equal, but in B. heineanus, the pyrenes are much longer than wide. In some specimens, the endocarp has a number of internal flanges that penetrate the seed. The flanges are perpendicular to the main endocarp wall and are only visible when the pyrene is viewed in transverse section. A sectioned pyrene in the type specimen does not have internal flanges. This character distinguishes Borassodendron (with internal flanges) from all other Borassus species and could indicate that a second unidentified Borassus species occurs in New Guinea. However, no additional morphological characters could be found to distinguish between specimens with or without internal flanges. The adaptive significance of these flanges is uncertain. While living material of B. heineanus has never been collected outside New Guinea, two endocarps (Degener & Degener 24625, BH) found on a beach on the Pacific island of Canton (Phoenix Is., Kiribati) were identified as belonging to Borassus (Degener & Degener 1974) and are probably attributable to this species. The endocarps are rather long and narrow and have perpendicular internal flanges (see Gunn & Dennis 1976: 177). These characters set them apart from all other Borassus species. However, typical endocarps of B. heineanus have a small hole in the apex to allow the cotyledonary stalk to exit. The Canton endocarps have deep V-shaped clefts at the apex, usually filled with black fibres (fibres eroded in one pyrene). There is a great deal of natural variation in the endocarps of better-known Borassus species. Perhaps when more material is collected in New Guinea, the presence of internal flanges or apical V-shaped clefts in the endocarp will fit into the natural range of variation exhibited by B. heineanus. (R.P. Bayton. 2007)/Palmweb. |
Culture
This palm may also be cultivated. Cold Hardiness Zone: 11
Comments and Curiosities
Etymology: After Georg Heine, administrator with the German New Guinea Company, who collected the type specimen.
Conservation: Data deficient. Borassus heineanus has been collected in only seven locations in New Guinea. Kjær (2003) reported a stand of approximately 300 × 300 metres in an area by the Sepik River in Papua New Guinea. Additional localities may exist, and further collections are needed. (R.P. Bayton. 2007)/Palmweb.
- IMAGE GALLERY
PNG National Botanic Garden, Morobe, Papua New Guinea. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Papua New Guinea. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Lae Botanic Garden, Papua New Guinea. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Papua New Guinea. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Papua New Guinea. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Papua New Guinea. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Lae Botanic Garden, Papua New Guinea. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
A 30 m tall individual of Borassus heineanus towering over the village of Maramba: notice the villagers at the foot. The palm was grown from a seed planted about 60 years ago as a symbol of the ties between the old settlement, Kamangauwi Village, near the main population of Borassus heineanus, and the new settlement in Maramba Village. Photo-palms.org.
Close-up of 30m palm in Maramba Village. Photo-palms.org.
The “Spirit House” in Maramba Village. More than 20 canoe loads of Borassus leaves were brought the long way down the Sepik River to built the house in the traditional ways of the ancestors. Large parts of the roof and the pale parts of the walls was constructed with Borassus leaves, and for the rest, sago leaves were used. Photo-palms.org.
Field assistant David Hambut with a leaf and an infructescence of Borassus heineanus. Photo-palms.org.
Queensland, Australia. Photo by Luke Nancarrow.
Queensland, Australia. Photo by Luke Nancarrow.
Borassuss heineanus for Palms of New Guinea, published also in Kew Bulletin, Volume 62(4), 2007, 561-586 (p. 570). pen and ink on bristol board.
Papua New Guinea. Photo by Dr. Anders S. Baford/Palmweb.
External Links
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- http://www.palms.org/palmsjournal/2003/bheineanus.htm
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).
Bayton, R.P.2007. A revision of Borassus L. (Arecaceae). Kew Bulletin 62: 561-586.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.
