No abstract

HA, C. O., SANDS, V. E., SOEPADMO, E. & JONG, K., 1988. Reproductive patterns of selected understorey trees in the Malaysian raia forest: the apomictic species. Garcinia is the predominant representative of the Clusiaceae in the understorey of the lowland rain forest of Peninsular Malaysia. In Pasoh Forest Reserve the dioecious species G. paruifolia was investigated since no male trees, but only trees with structurally hermaphodite flowers which later set fruit, were found there. Pollination and embryological studies indicated a condition of non‐pseudogamous agamospermy, with no viable pollen grains being formed in the staminodes, and the unfertilized egg cell giving rise to the embryo. Supportive studies were made of microspore development in G. forbesi, and of embryogenesis and seed development in G. malaccensis and G. scortechinii which also appear to be agamospermous. The role of either facultative or obligate apomixis in gene fixation in these dioecious species is discussed, and the possible adaptive significance of reproductive versatility among certain rain forest trees is examined.

HA, C. O., SANDS, V. E., SOEPADMO, E. & JONG, K., 1988. Reproductive patterns of selected understorey trees in the Malaysian rain forest: the sexual species. Investigations were carried out on the floral, fruit and seed biology, and the embryology of representatives of the Sapindaceae and Bombacaceae which occur in the lower canopy of the lowland rain forest of Peninsular Malaysia. Pollination studies indicated cross‐compatibility and outbreeding in all species examined, associated with self‐compatibility in the polygamous monecious Pometia pinnata and Allophylus cobbe and, to a limited extent, in the effectively dioecious Xerospermum intermedium. In these sapindaceous species, together with the self‐incompatible androdioecious Nephelium lappaceum, the structurally hermaphrodite flowers were determined embryologically to be functionally female with no anther dehiscence. The self‐incompatible Durio griffithii of the Bombacaceae, and X. intermedium, N. lappaceum and P. pinnata were shown by embryological studies to form a sexual zygote. The observations on these outcrossing species are considered in relation to their potential for gene exchange and their contribution to the maintenance of species diversity in the lowland rain forest.