Adinandra

Abstract: Adinandra belukar is a species-poor forest dominated by Adinandra dumosa (Theaceae) found in Singapore and southern Peninsular Malaysia. It is the product of secondary succession after exhaustive agricultural exploitation on land cleared of primary lowland rain forest. A high degree of similarity in vegetation between different sites was found for seven 225 m2 plots in a dinandra belukar in Singapore. Adinandra dumosa was dominant or codominant in all plots, generally found in association with the woody species Dillenia suffruticosa, Fagraea fragrans, and Rhodamnia cinerea, the climber Gynochthodes sublanceolata, the fern Dicranopteris linearis and the terrestrial orchid Bromheadia finlaysoniana. All sites had extremely acidic (pH 3.3–3.9) surface (0–20 cm) mineral soils with very low total nitrogen (0.06–0.14%) and total phosphorus (11–29 μg g-1) contents and very high carbon/nitrogen ratios (33–48). Adinandra belukar is interpreted as a heath forest because of its floristic and physiognomic similarities with this forest formation.

Abstract: During the past three decades, molecular taxonomy has made considerable changes in the systematic delimitations of several families in the order Ericales which were formed earlier based on morphology. For instance, the Pentaphylacaceae s.l. has been treated differently by both modern and traditional taxonomists. Modern molecular taxonomists constituted this family by combining the traditionally defined Pentaphylacaceae s.s. (Pentaphylax), Sladeniaceae s.s. (Sladenia), the subfamily Ternstroemioideae with 11 genera of Theaceae s.l. and the genus Ficalhoa. There are also treatments placing the genus Pentaphylax with Ternstroemioideae in Pentaphylacaceae and Ficalhoa with Sladenia in Sladeniaceae. Because most of these genera are poorly studied, investigations on all aspects are important to understand the phylogeny to settle the issues surrounding the treatment of the 14 genera in this family. In the present study, DNA sequences of nrITS and trnL-F genes from species of 11 genera from these 14 genera were generated and analyzed together with sequences from other closely related members of Ericales. The results suggested existence of four distinct lineages viz., Sladenia, Pentaphylax, and tribes Frezierieae (9 genera) and Ternstroemieae (2 genera). Further, it demonstrated that within the biggest lineage, Frezierieae, the Visnea remained sister to the clades Adinandra+Cleyera, Euryodendron+Symplococarpon, Freziera, and finally, Eurya. Based on the evidence, it can be concluded that Sladeniaceae and Pentaphylacaceae are very close to each other and the proposal of merging them into a mega family Pentaphylacaceae s.l. with four tribes, i.e., Sladenieae, Pentaphylaceae, Ternstroemieae, and Freziereae should be considered seriously.

Abstract: . Sun leaves from 37 species of tree and shrub were collected in four forest types on Pulau Ubin, Singapore. Evidence of habitat-related variation in the form of leaves is presented. The species were from the habitats: mangrove, beach forest, adinandra belukar (secondary forest on degraded soils) and secondary forest on undegraded soils. The mangrove forest species sampled had thicker leaves with a lower specific leaf area than the beach forest species. Leaves of species from the adinandra belukar were thicker and smaller, with more dry weight per unit area, than those of pioneers from undegraded sites. This is interpreted as oligotrophic xeromorphy in adinandra belukar.