Flavonoids of Vernonieae and Liabeae
According to Jones (1977), Vernonieae consist of about 70 genera and something in excess of 1450 species. Bremer (1994) circumscribed the tribe to comprise 98 genera owing in part to new genera described by H. Robinson during the period 1987-1992 (See Bremer, 1994, for pertinent references), but his species count is around 1300. Robinson (1996a) includes 111 genera. Thirty-seven genera in Jones’ (1977) treatment are monotypic; 46 are monotypic in Bremer’s (1994). The subtribal classification of Vernonieae is at present in a state of flux (Bremer, 1994; Robinson, 1996a). Central to the problem is the large genus Vernonia, which is now undergoing increased taxonomic scrutiny. New genera will no doubt continue to be peeled off from the core taxa, especially in the Old World, whether rightly or wrongly remains to be seen. This tendency, in fact, has already been the main impetus for generic inflation since 1977 (70 genera in Jones, 1977, vs. 111 in Robinson, 1996a). Jeffrey (1988) has suggested some informal groupings in Vernonia of East Tropical Africa that could eventually be considered for generic status. For consistency we have chosen to follow the generic concepts developed by Robinson, which he summarized in 1996a (presented also by Bremer, 1994). Number of included species and distributional ranges are after Bremer (1994) unless stated otherwise. An important new synthesis of American Vernonieae, containing a valuable list of generic and specific names (with synonyms), recently has been published by Robinson (1999), but this paper was not available to us at the time our manuscript was prepared.
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