IAWA Bulletin n.s., Vol. 11 (1), 1990: 61-70 RATIANS - STEM ANATOMY AND TAXONOMIC IMPLICATIONS by Gudrun Weiner and Walter Liese'" Ordinariat fUr Holzbiologie, Universitat Hamburg, Leuschnerstrasse 91, 2050 Hamburg 80, F. R. G. Su.mmary Introduction The stem anatomy of 114 species of the Rattans, the climbing palms, belong to the 13 rattan genera of the subfamily Calamoi­ subfamily Calamoideae (Uhl & Dransfield deae has been examined and described. Char­ 1987). This subfamily is composed of 22 acters of taxonomic and diagnostic signifi­ genera with more than 650 species. Of these cance are the number of metaxylem vessels 13 are rattan genera which occur in two geo­ and phloem fields in the vascular bundles, graphic regions: West Africa, with 4 genera the type of ground parenchyma, and the tis­ of which three are endemic (Eremospatha, sue arrangement in the cortex. The 13 rattan Laccosperma, Oncocalamus, Calamus), and genera can be distinguished on the basis of Southeast Asia, the much larger and more these features. important area with ten genera (Fig. 1). Of There is a distinct correlation between these latter genera, nine are present in Penin­ anatomical features and the taxonomical sub­ sular Malaysia, although the most species­ division of the Calamoideae. Hapaxanthic rich area is Borneo (Dransfield 1981). rattans possess one phloem field in the vas­ In both Peninsular Malaysia and Borneo cular bundles, while the pleonanthic rattans rattan is of considerable economic impor­ have two phloem fields. Taxonomic relation­ tance. However, only about 20 species are ships can be strengthened by such anatomical traditionally used in furniture production, a evidence. major commodity, whereas others are said to Key words: Palmae, Calamoideae, rattan, be of poorer quality. stem anatomy, vascular bundles, phloem, This investigation is an attempt to differ­ xylem, parenchymatous tissue, morphol­ entiate the rattan genera on the basis of ana­ ogy, taxonomy. tomical differences. A further study will deal ~ Distribution of the rattan genera Fig. l. Distribution of the rattan genera. '" Dedicated to Prof. Dr. Helmut J. Braun on his 65th birthday. Downloaded from Brill.com10/06/2021 10:24:47AM via free access - 0- o 62 IAWA Bulletin n.s., Vol. 11 (1), 19900- Downloaded from Brill.com10/06/2021 10:24:47AM via free access Weiner & Liese - Stem anatomy of rattans 63 with possible relations between anatomical The samples were boiled in distilled water structure and certain properties. and embedded in polyethylene glycol (PEG) 2000 MW (Weiner & Liese 1988). Trans­ Material and Methods verse and longitudinal sections were double­ In this study 114 species of the 13 rattan stained with acridin/chrysoidin red and astra­ genera were examined (Table 1). blue. For macerations Jeffrey's method was used. Table 1. Investigated material. Results and Discussion Genus Number of General anatomy of rattan species investigated The stem anatomy of the rattans corre­ sponds to the general structure of the mono­ Calamus 44 cotyledons, represented by collateral vascular Calospatha 1 bundles embedded in ground parenchyma. Ceratolobus 6 The stem is covered by an epidermis consist­ Daemonorops 13 ing of a single cell layer (see Fig. 10). The Eremospatha 2 thickness of the cuticle and the form of the Korthalsia 25 epidermal cells vary (Siripatanadilok 1983). Laccosperma 2 The cortex between epidermis and the vas­ Myrialepis 1 cular system consists of parenchyma cells, Oncocalamus 1 fibres and incomplete vascular bundles. The Plectocomia 9 endemic genera from West Africa possess Plectocomiopsis 5 fibre rows below the epidermis (Fig. 11); the Pogonotium 2 Asian genera, however, have fibre strands Retispatha 3 (Fig. 10). The central cylinder begins with the first Information about the herbarium vouchers fully developed vascular bundles, which is available from the authors. Only specimens form a complete circle in all genera. In the used for illustrations or of species with an inner part of the culm the vascular bundles aberrant anatomy are cited in this paper. are diffusely scattered. The material came from: Australia, China, The vascular bundles consist of the con­ India, Indonesia, Malaysia, New Guinea, the ducting tissue, phloem and xylem, and fibres Philippines, Sri Lanka, Taiwan, Thailand and which provide structural support (Fig. 2). West Africa. Most of the samples were taken The phloem consists of sieve tubes with from herbaria. For this reason the exact loca­ companion cells. Parthasarathy (1968) re­ tion of within-stem samples is not recorded. corded simple sieve plates in transverse to Some material was collected in the field with oblique end walls for this subfamily with the an adequate record of the sample location. exception of the genera Eremospatha and Fig. 2. Plectocomia elongata Becc. (FRI 36081). Vascular bundle with one phloem field and one metaxylem vessel, cross section; FS = fibre sheath, PH = phloem field, MX = metaxylem vessel, PX = protoxylem, PS= parenchyma sheath. -,Fig. 3. Myrialepis paradoxa Becc. (FRI 36057). Vascular bundle with one phloem field and two metaxylem vessels, cross section.­ Fig. 4. Plectocomiopsis wrayi Becc. (FRI 36074). Cross section: ground parenchyma type C. - Fig. 5. Plectocomiopsis geminiflora (Griff.) Becc. (FRI 36077). Longitudinal section: ground parenchyma type C. - Fig. 6. Calamus caesius Blume (DRI 36076). Vascular bundle with two phloem fields and one metaxylem vessel, cross section. - Fig. 7. Calamus caesiu Blume. Cross section: ground parenchyma type A. - Fig. 8. Daemonorops angustifolia (Griff.) Mart. (FRI 36056). Cross section: ground parenchyma type B. - Fig. 9. Calamus manan Miq. (FRI 36068). Longitudinal section: ground parenchyma type A and B 'stacks of coins'. Downloaded from Brill.com10/06/2021 10:24:47AM via free access > 64 IAWA Bulletin n.s., Vol."0 11 (1), 1990 Downloaded from Brill.com10/06/2021 10:24:47AM via free access Weiner & Liese - Stem anatomy of rattans 65 Laccosperma. In these genera simple or tran­ Noteworthy are also the 'yellow caps', sitional sieve plates occur mixed with very i.e., fibre sclereids at the outer side of the oblique compound ones. In the present study fibre sheath of the first vascular bundles be­ also the Calamus species were found to have low the cortex (Fig. 12). Because of their compound sieve plates in very oblique end striking appearance they have been named walls (Fig. 15). The length of a sieve tube 'yellow caps' by Siripatanadilok (1974). The member varies from one to more than three feature 'yellow cap' is present only in the rnillimetres. genera Korthalsia, Myrialepis, Plectocomia, Regarding the arrangement of the phloem and P lectocomiopsis. two types have to be distinguished: one The parenchyma sheath always covers the phloem field (Fig. 2) or two separate fields metaxylem vessel(s) and the protoxylem tra­ (Fig. 6). Also of interest is the arrangement cheids. Parenchyma cells in direct contact of the sieve tubes within a phloem field with a metaxylem vessel are of elongated rec­ (Figs. 18, 19). tangular fonn with an intensive pitting of the The xylem is composed of metaxylem, cell walls (Fig. 17). The other parenchyma protoxylem and an associated parenchyma cells of this sheath have not such intensive sheath. The metaxylem consists of either one pitting and their fonn is more roundish. (Fig. 2) or two (Fig. 3) vessels. The diam­ The ground tissue consists of isodiametric eter of metaxylem vessels varies from 150- parenchyma cells with simple pits. Three 250-450 ~m. In the genera Pogonotium and fonns can be distinguished in a cross section: Retispatha the metaxylem vessels are much Type A: cells are weakly branched leaving smaller (130-140 ~m) than in the other regular rounded intercellular spaces be­ genera. The vessel perforations are mostly tween them (Fig. 7); simple. Bhat et al. (1988) describes multiple Type B: smaller, rounded cells with irregu­ perforation plates in smaller metaxylem ves­ larly shaped intercellular spaces (Fig. 8); sel elements for Calamus species. These sca­ Type C: cells thin-walled, large and round larifonn perforations have been observed with relatively small intercellular spaces also in some of the other investigated genera. (Fig. 4). The cell walls exhibits oval, half-bordered pits in an opposite arrangement (Fig. 16). When viewed in a longitudinal section types The protoxylem tracheids bear annular or A and B appear like 'stacks of coins' (Fig. 9). helical secondary wall structures. The dia­ Type C shows short and elongated cells ori­ meter of the protoxylem tracheids is 30-80 ented perpendicularly to each other (Fig. 5). Ilm, i. e., much smaller, than that of the meta­ Some other features, e.g. so-called 'ducts', xylem vessels. raphides and silica bodies (Fig. 13) or 'steg­ The phloem and xylem are surrounded by mata' recorded by Tomlinson (1961) appear­ fibre and parenchyma sheaths (Fig. 2). The ed to be present in all genera investigated. size of the fibre sheaths differs between spe­ cies. The fibres are one to three millimetre Structural features of taxonomic significance long, often contain septa and generally have Based on a comprehensive anatomical polylamellar cell walls (Fig. 14) (Parames­ analysis of the 114 species from the 13 gen­ waran & Liese 1985). era, the following parameters were found to Fig. 10. Ceratolobus subangulatus (Miq.) Becc. (FRI 36064). Cross section: epidermis (EPI) and cortex with fibre strands (arrow). - Fig. 11. Laccosperma secundiflorum O. Kuntze (Dransfield 7253, K). Epidermis and cortex with fibre rows below the epidermis (arrow). - Fig. 12. Korthalsia rigida Blume (FRI 36063). First vascular bundles with the 'yellow caps' (arrow). - Fig. 13. Calospatha scortechinii Becc. (FRI 36070). Si02 body, longitudinal sec­ tion; x 5,000. - Fig. 14. Calamus caesius Blume (FRI 36076). Cross section of vascular fibres exhibiting polylamellate walls; x 3,800. Downloaded from Brill.com10/06/2021 10:24:47AM via free access 66 IAWA Bulletin n.s., Vol. 11 (1), 1990 Fig. 15. Calamus manan Miq. (FRI36068). Sieve tube with compound sieve plate in very oblique end wall.