Plectocomiopsis

Abstract: Summary. The taxonomy and morphology of the Calamus longipinna (Arecaceae) group is revised and discussed. This group of rattan species from New Guinea and the Solomon Islands is defined by the possession of a distinctive, inflated ocrea at the mouth of the leaf sheath and rather uniform A striking feature of the New Guinea species of the rattan genus Calamus is the frequent presence of elaborate ocreas. The ocrea is widespread in some other rattan genera, namely Korthalsia, Plectocomiopsis, Laccosperma, Eremospatha and Oncocalamus. In most cases, the structure is merely a low, inconspicuous, tubular extension of the leaf sheath above the insertion of the petiole. However, in some species of Calamus, Korthalsia and Laccosperma, the ocrea is enlarged, highly conspicuous and widely variable in morphology. For example, some ocreas are inflated and clasp the stem or diverge from it at an acute angle. Ants often colonise inflated ocreas, cultivating scale insects for honeydew on the leaf sheaths and aggressively defending their home, and, at the same time, the rattan (Dransfield 1979). In a few species of Korthalsia and one species of Calamus, the ocrea consists of a reticulum of fibres which is tightly adpressed to the sheath or else expands into an open funnel. A number of Calamus species (e.g. C. paspalanthus Becc. in west Malesia and C. zebrinus Becc. in New Guinea) possess greatly enlarged ocreas, sometimes as long as 1 m or more, that disintegrate and fall not long after emergence. Approximately 14 species of Calamus in New Guinea possess such enlarged ocreas. The C. longipinna Lauterb. & K. Schum. group, the subject of this paper, is characterised by its inflated ocreas that clasp the stem and a characteristic yet rather simple flagelliform inflorescence morphology. The group is distinguished from the ocreate species related to C. macrochlamys Becc. and C. zebrinus Becc. because it does not possess the unusual floral cluster architecture that is so remarkable in this group (Dransfield & Baker, submitted). Calamus humboldtianus Becc. is not included in the C. longipinna group because it bears bizarre inflorescences with congested branches as well as unusual leaf and ocrea morphology. The fibrous, fragile ocrea and robust rachillae of C. klossii Ridl. set it apart from other New Guinea ocreate rattans. Calamus distentus Burret may yet prove to be a relative of the C. longipinna group, but the ocrea diverging from the stem and very slender inflorescence morphology are not congruent with such a placement.

Abstract: Summary. The generic limits of the rattan palm genera Plectocomiopsis, Myrialepis and Bejaudia are re-examined and Bejaudia reduced to synonymy with Myrialepis. Areas of nomenclatural and taxonomic confusion are discussed. A new combination, Myrialepis paradoxa, is published for the only species in the genus, and five species are recognized in Plectocomiopsis, one of them new. Plectocomiopsis and Myrialepis are dioecious, hapaxanthic rattan genera found in the South East Asian region. Although two taxa, one in each genus, are abundant in disturbed habitats in botanically relatively well-known Malaya, they and their genera remained obscure until relatively recently. Beccari described the genus Plectocomiopsis to accommodate Griffith's Calamus geminiflorus which because of inflorescence details was obviously misplaced in Calamus. In coining the generic name, Beccari hinted at similarities with another Asiatic rattan genus Plectocomia. Specimens collected by Father Scortechini of a rattan somewhat resembling Plectocomiopsis geminiflora in inflorescence structure but bearing superficially very different fruit covered in minute scales, were the basis for another new genus, Myrialepis. As Beccari described it, Myrialepis was defined by this fruit character; thus staminate material without accompanying fruit could not be matched. Although Myrialepis was defined by fruit characters, Beccari transferred Calamus triqueter to it, a curious Bornean rattan with three-angled stems known at that time from sterile material only. Later Beccari referred Calamus triqueter to synonymy with Plectocomiopsis geminiflora var. borneensis; however, even this has proved to be incorrect (Dransfield 1980)-Calamus triqueter represents a quite distinct species of Plectocomiopsis. Calamus paradoxus was described by Kurz, based on a staminate specimen from Burma and then transferred by Beccari to Plectocomiopsis; during the present study it has proved to belong to the genus Myrialepis. Adding further confusion, Gagnepain described a new genus Bejaudia based on very imperfect staminate material from Cambodia; Gagnepain indicated the affinity of this genus with Plectocomiopsis and Myrialepis but distinguished it mainly on the structure of the flower. Gagnepain's interpretation is however totally erroneous, and Bejaudia is shown

Abstract: Rattans are one of the most unique and economically important plants for most tropical countries. There is however, a lack of interest in the specific study of the rattan spines. In this paper, we tested a new hypothesis concerning the functional role of rattan spines. We proposed that rattan spines also serve as a visual deterrent against herbivores or seed predators. In our proposed method we used an Imaging software, ImageJ, to measure the spine area of four species of rattan (Calamus insignis, Myrialepis schortechinii, Plectocomiopsis geminifloru s and Calamus caesius) from two different orientations (root to shoot and vice versa). Our results showed that rattan spines were very heterogeneous and highly variable between different species. One common trait that the rattan spines share is that spine area measurements of shoot to root (ShR) are larger than root to shoot (RH) orientation. We propose that the downwards spine angle might be specifically designed to discourage climbing leaf and seed predators.

Abstract: Rattan is a potential non-timber forest product. It grows in almost all parts of Indonesia, and has been widely used and traded. Indonesia as the largest rattan producer in the world supplies about 85% of world rattan needs. Bukit Lubuk Pekak Forest is part of the Production Forest Management Unit (KPHP) area, Merangin District, Jambi Province. The threat form rattan exploitation is increasing, especially in the Bukit Lubuk Pekak. Therefore, it is necessary to conduct study on the potency of rattan in that area for future conservation efforts. This study aimed to investigate rattan species in Bukit Lubuk Pekak forest, Merangin District, Jambi Province. Information of the potency of rattan is essential to support rattan industries. To complete data of rattan potency from Sumatra, an exploration in this area was carried out in July 2016 in Bukit Lubuk Pekak Forest. The study was conducted by purpossive sampling. Identification on morphological characteristics of rattan were performed on all parts of plants including fruits and seeds (if available). The results showed that there were four rattan genus in Bukit Lubuk Pekak Forest: Calamus, Daemonorops, Korthalsia, and Plectocomiopsis. They consisted of nine species, namely Calamus caesius , C. exillis , C. insignis var. longispinosus , C. laevigatus , C. tumidus , Daemonorops micracantha , D. didymophylla , Korthalsia flagellaris , and Plectocomiopsis geminiflora . Among the nine species, two species that is Calamus caesius and Daemonorops didymophylla have been cultivated for industry raw materials and drug, respectively.