Plant Ecology 133: 153–167, 1997. 153 c 1997 Kluwer Academic Publishers. Printed in Belgium. Convergent seed germination in South African fynbos and Californian chaparral Jon E. Keeley 1 & William J. Bond 2 1 Department of Biology, Occidental College, Los Angeles, CA 90041, USA; 2 Botany Department, University of Cape Town, Rondebosch 7700, South Africa; Present address: Division of Environmental Biology, National Science Foundation, Arlington, VA 22230, USA Accepted 11 February 1997: accepted in revised form 20 July 1997 Key words: Chaparral, Convergent Evolution, Fynbos, Germination, Heat-shock, Phylogenetics, Smoke Abstract California chaparral and South African fynbos are fire-prone communities dominated by species exhibiting remark- able similarities in germination response. In both regions there are a substantial number of species with germination stimulated chemically by charred wood and smoke. This type of germination behaviour has arisen independently in distantly related families and is interpreted as convergent evolution. Heat-shock is also an important germination trigger that is widespread, although in both regions it is most common in the same families. Phylogeney may play an important role in the presence of this postfire germination cue in both regions, but a much more rigorous analysis is required to show that this trait represents a single unique event in each lineage. In both regions, germination response is not randomly distributed across growth forms and there are marked regional similiarities in the type of germination behaviour associated with certain growth forms. Geophytes largely lack refractory seeds, which require fire-type cues for germination, but the presence of fire-stimulated flowering of bulbs and corms may time recruitment to subsequent postfire years. Annuals that cue germination to postfire conditions are predominantly triggered by chemicals from smoke and/or charred wood. Nomenclature: Follows Hickman (1993) and Bond & Goldblatt (1984) with exceptions as noted. Introduction Mediterranean-climate ecosystems are commonly cited examples of convergent evolution in vegetation structure and function (di Castri & Mooney 1973; Mooney 1977; Cowling & Campbell 1980; Shmida & Whittaker 1984; Arroyo et al. 1994; Keeley 1992). These landscapes are dominated by sclerophyll ever- green vegetation that dry sufficiently during the long summer droughts to produce a predictable and exten- ded wildfire season (Mooney & Conrad 1977). There is evidence that species in these communities have evolved to exploit fires for population expansion and some have adapted to these disturbances to the extent that they are ‘fire-dependent’ for completion of their life cycle (Gill 1981; Kruger 1983; Keeley 1986; van Wilgen et al. 1992; Trabaud & Prodon 1993). Many species regenerate primarily in the first year or two after fire, either because fire stimulates flowering, or seed release from serotinous cones or breaking of seed dormancy by heat or from chemicals in charred wood or smoke. Despite widespread postfire recruitment in mediterranean-climate floras, communities include species representing other recruitment patterns as well. For example, in Californian chaparral disturbance- dependent recruitment from dormant soil seed banks characterizes a substantial portion of the flora, but a sig- nificant number of species recruit solely in the absence of fire (Keeley 1991). While postfire disturbance- dependent species produce deeply dormant seeds with germination triggered by heat or chemicals, spe-