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obscures intrapopulation variability that may occur in some heterostylous species, 
or variation in breeding systems that occurs over a period of years (e.g. Ornduff 
1976, 1980). Other more detailed methods of reporting seed-set data have revealed 
interesting intrapopulation differences in breeding systems (e.g. Ganders 1979a,b; 
Nicholls 1985; Barrett and Anderson 1985; Glover and Barrett 1986) as well as 
interpopulation differences (e.g. Weller 1979, Barrett 1985). Villarsia exaltata shows 
plant-to-plant differences in fecundity after various pollination combinations in both 
morphs and some pins show unexpectedly high levels of seed-set following what 
should be incompatible crosses. In these respects, the breeding system of this species 
parallels that of the Western Australian V. lasiosperma F. Muell. (Ornduff 1992), 
which is considered by Aston (1969) to be a close relative of V. exaltata. 
As mentioned above, 10 of the 15 species of Villarsia have distylous flowers and four 
have flowers that are not heterostylous. The breeding system associated with distyly 
in the South African V. capensis (Houtt.) Merrill (Ornduff unpublished), the Western 
Australian V. capitata Nees (Ornduff 1982), V. congestiflora F. Muell. (Ornduff 1988a), 
and V. latifolia Benth. (Ornduff unpublished) appears to be more or less conventional, 
i. e., with generally strong intramorph incompatibility and high levels of intermorph 
compatibility. The Western Australian V. calthifolia F. Muell. and V. violifolia F. Muell. 
have distylous flowers but with high levels of intra- and intermorph compatibility 
of both morphs (Ornduff unpublished). The distylous Western Australian 
V. marchanlii Ornduff (Ornduff unpublished) and V. parmssiifolia (Labill.) R. Br. 
(Ornduff 1986, in press) have pins with strong intramorph incompatibility, but thrum 
X thrum pollinations are relatively fecund. The Western Australian V. albiflora F. Muell. 
(Ornduff 1986, in press) and V. submcrsa Aston (Ornduff unpublished) have flowers 
that are not heterostylous, exhibit strong self-incompatibility, and high interplant 
compatibility. The eastern Australian V. reniformis R. Br. has flowers that are not 
heterostylous, but it is uncertain whether the species is uniformly self-incompatible, 
self-compatible, or exhibits both conditions (Ornduff unpublished). The southeastern 
Australian V. umbricola Aston likewise has flowers that are not heterostylous, but 
these are highly self-compatible, show high levels of autogamy, and are probably 
recombinant homostyles (Ornduff unpublished). 
The small genus Villarsia exhibits a diversity of breeding systems, most of which seem 
to be derived from an ancestral, conventional distyly. The significance of intraspecific 
variation in distylous breeding systems in this genus is unknown, but the unexpected 
features in breeding systems that characterize V. marcliaiitii and V. pamassiifolia could 
have developed only from an ancestral distylous breeding system in which conventional 
morphological distyly is associated with relaxed incompatibility in one or both morphs. 
The breeding system of V. exaltata does not represent a postulated ancestral condition of 
any derivative breeding system known in the genus. However, the plant-to-plant variation 
in breeding system found within the single population studied of this species is a 
prerequisite condition to the breakdown of distyly that has occurred elsewhere in the 
genus. Much remains to be discovered about the breeding system of V. exaltata: for 
example, we know nothing of morph ratios of pin and thrum plants in the field, its 
pollination biology, fecundity of the two morphs under field conditions, or interpopulation 
differences in breeding system and the morphological expression of distyly. These merit 
study by botanists who are resident in the natural range of this species. 
Acknowledgements 
I thank the staff and volunteers of the North Coast Regional Botanical Garden at 
Goffs Harbour and John A. West for providing seeds of Villarsia exaltata, and Helen 
Aston and Robert Whelan for helpful comments on an earlier draft of this paper. 
