Studies of reproductive characters in Laurales as a tool for oriqin of monocots

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Tobe investigated embryology of Monimiaceae and Gomortegaceae and observed anatomical development of anthers, ovules, and seeds. Takahshi worked with Lauraceae a tectate pollen and additionally worked with fossil pollen from Cretaceous of Fukushima Pref.in order to contribute to understanding of the geographic depth of origin of monocotyledons.Concerning embryology of lauralean families, four of the five subfamilies of monimiaceae (Hortonioideae, Atherspermoideae, Siparunoideae, and Mollinedioideae) were studied. As a result, Monimiaceae were found to have an outer integument shorter than an inner integument, non-pachychalazal ovules or seeds. In addition, as incompletely reported previously, the family, for instance, Atherospermoideae, have a glandular, rather than amoeboid, anther tapetum. Gomortegaceae also were found to have non-pachychalazal ovules or seeds in agreement with Monimiaceae, but, unlike Monimiaceae, were clarified to have an outer integument as long as an inner integument for the first time.As regards pollen of Lauraceae, it was discussed that it is classified as a non-aperturate pollen destitute of tectum but has an extremely thin sporopollenin wall with micropapillae dispersed on surface. Intine is thick, in which tuberous structures are characteristically radially interspersed. Fossil pollen from late Cretaceous of Fukushima Pref.is likely to be one of monocots, suggesting that monots were already diversified early in evolution of angiosperms.