Comparative embryological study of Dipterocarpaceae with the putative related taxa

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We have studied embryology of four species of three genera (Dipterocarpus, Shorea and Vateriopsis) in dipterocarpaceae. Thirteen embryological features common to three genera are found as follows : 1) The ovule is anatropous, 2) The ovule is bitegmic, 3) both the inner and outer integuments are 3-9 cell-layered, 4) The megaspore mother cell produce a linear tetrad, 5) The embryo sac is Polygonum type, 6) Vasculatures are observed in only outer integument, 7) Matured embryosac is ellipsoidall in shape, 8) Endosperm formation is the Nuclear type, 9) the perisperm is absent, 10) The funicle is very short, 11) the embryo in mature seed is symmetrical, 12) the short palisadal cells are formed in exotegmen, 13) The anther is tetrasporangiate without fibrous endothecium.However, three embryological features different among three genera are found as follows : 1) the micropyle is formed by both the integuments in Dipterocarpus and Vateriopsis, but by the only inner integument in Shorea, 2) The pachycharazy is formed in only Vateriopsis, 3) The hypostase is formed in Dipterocarpus and Shorea.Thus, we suggest that Dipterocarpus is more related with Shorea than Vateriopsis by the embryological features up to the present time.