II. LITERATURES REVIEW
2.1. Malesia Region
Malesia is the floristic region that comprises the following political entities: Malaysia, Singapore, Indonesia, East Timor previously Portuguese
Timor, the Philippines, Brunei Darussalam, and Papua New Guinea. The concept and demarcation of this floristic region was firstly proposed by Van
Steenis in the late 1940’s, under the name “Malaysia” Van Steenis 1950. To avoid confusion with the State of Malaysia granted independence from
the British in 1953, the name Malesia was introduced to replace the previous name Whitmore 1975.
In the original demarcation Van Steenis 1950 did not include the islands surrounding the mainland of New Guinea, namely the Bismarck,
Solomon, and New Hebrides Archipelagos Figure 1. He explained that these islands were excluded mainly because knowledge of their floras was
limited. However, he suggested that the floras on these islands were mainly derived from Malesia. Furthermore, he noted that the demarcation of
Malesia without these groups of islands was artificial, thus the exclusion of the islands was basically for practical reasons only Van Steenis 1950. Van
Steenis concluded that the Indo-Asiatic flora ends rather abruptly in the mainland of New Guinea. The studies of Van Balgooy 1971 support the
suggestion by Van Steenis that the floras of the Bismarck, Solomon and New Hebrides Archipelagos indeed share many similarities with the
Malesian flora rather than with the Australian flora. Ever since the flora and fauna of the Malay Archipelago have been
known to science, major patterns of distribution have been evident. Wallace was the first to highlight these in 1863 Wallace 1863; Hall 1998.
Impressed by the disjunction in animal distributions Wallace drew a line on the map passing down the Makassar Strait, later known as Wallace’s line
Figure 2. Wallace divided the Malay Archipelago into three separate regions, Indo-Malayan now Sunda continental shelf in the west, Austro-
Malayan now Sahul continental shelf in the east, and a region in the centre
consisting of the Philippines, Celebes, Moluccas and the Lesser Sunda Islands Nusa Tenggara. Later Dickerson 1925; 1928 proposed the name
Wallacea for this “region in between”. Combining Wallace’s line, at least between Borneo and Celebes, with
his own studies on plant generic distribution in the Malay Archipelago, Van Steenis 1950; 1954; 1979; Van Balgooy 1987 proposed three areas, known
to him as “demarcation knots”, which are not crossed by many genera in either direction. He thus divided Malesia into three divisions, West Malesia
including the Malay Peninsula, Sumatra, Borneo, and the Philippines, East Malesia including Celebes, Moluccas, and New Guinea with its nearby
islands, and South Malesia including Java and the Lesser Sunda Islands. This division was later revised by Van Balgooy in 1960 Van Balgooy
1971, who showed that almost the whole tropical Pacific belongs floristically to East Malesia. Furthermore, he considered that the most
logical division of the Indo-Malesian region would be into three sub-regions or divisions, namely South-east Asia, West Malesia comprising Van
Steenis’ West and South Malesia, and Papua comprising New Guinea, Celebes, Moluccas, and the tropical Pacific excluding New Caledonia. This
Papuan sub-region can be regarded as equivalent in some respects to Van Steenis’ East Malesia. Thus there are only two divisions within Malesia,
West and East. This division is generally accepted at the present day and is followed in this study.
Fig. 1. Malesia and its divisions as described by Van Steenis 1950
Fig. 2. Wallace’s line.
2.2. History of Classification of Popowia Endl.
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