Malayan Bignoniaceae, their taxonomy, origin and geographical distribution

1. An outline of the taxonomy is given, together with the geographical distribution. 2. It has turned out that the monotypic genus Haplophragma P. Dop. (1925) possesses a second species in Sumatra, viz. H. macroloba (Miq.) vSts. 3. To emphasize the fact that the Australian Dolichandrone I's are separated from the other species, it is suggested that Dolichandrone (Fenzl.) Seem is constituted of 2 sub-genera, viz. Coriaceae vSts. (Australia) and Membranaceae vSts. (Africa, S. E. Asia, Malaya, New Guinea, New Caledonia). 4. A scheme of the phylogenetic relations within Tecomanthe H.Bn. is made, based on the structure of the ovary, together with the habitus and geographical distribution. (Fig. 16.) 5. There are striking indications that within Tecomanthe H. Bn. parallelly developed montane and alpine species can be distinguished. 6. The affinities with the neo-tropical Bignoniaceae make it probable that the Malayan Bignoniaceae have originated from neo-tropical ones and have taken part in a Tertiary flora. A hypothesis is made about the routes along which these tropical genera have migrated. Most probably they have gone along N. America, to N. E. Asia, China and Japan along the Behring-Straits Bridge and perhaps also along the Alutian Islands; the bulk of them belong to the Tecomeae-stem. One part has gone to the east: Malaya, Philippines, New Guinea and Australia. Others have migrated to British India and E. Africa, perhaps along the north of the Arabian Sea, but certainly also directly to E. Africa over Ceylon, the Mascarenes, Seychelles and Madagascar (Wegener). Thus the Bignoniaceae point to the same genetic-phytogeographical relations as many other families do. (Fig. 17). 7. The Bignoniaceae are most probably at least of Tertiary age. They show many endemic species and genera, but the latter often also with highly disjunct area's. These genera are partially extinct nowadays, but must have Ï possessed a greater spreading in earlier times. This fact cannot be explained with W i 11 i s’ “Age and Area” hypothesis, this theory being only of value for very young flora’s. Only in Radermachera and Tecomanthe some rather young species occur, these being progressive endemics, which can also easily be understood without the “Age and Area” hypothesis. My main argument against Willis is that generally one is unable to distinguish at first sight the difference between a progressive- and a relic-endemic. Only a close monographical study may clear up the phylogenetic relations. Relic-endemism is not rare in the Angiosperms and is not only due to Ice-ages, but relic-endemism is also to be found in the tropical primeval forests (and Rainforests), which also are. composed of members of earlier floras and are not only the result of progressiveendemic development in agreement with the ingenious outline of genetic-phytogeography of A. Eng 1er. Moreover “Age and Area” is a statistical (mathemathical) theory, not keeping account with the biological peculiarities of the species. 8. The geographical distribution of the Malayan Bignoniaceae may be explained by Weber’s Line, though some of them existed already in Malaya before this line represented a real barrier for biological distribution. Fig. 18.