In addition, qualitative differences in floral shape among clones was used to ensure that geitonogamous
pollinations were prevented.
These single-branch plants have no opportunity for between-branch geitonogamy and should, therefore, experience less geitonogamous
selfing than plants with multiple flowering branches, which had 5.
Considering the many simultaneous flowers produced by these species, the amount of nectar exuded, the hummingbird behavior, and the existence of SC, hummingbird visits likely favor geitonogamous
rather than xenogamous pollen transfer.
Although pollinator exclusion by bagging virtually eliminated fruit and seed production, geitonogamous
crosses (within plants, between flowers) produced normal fruit set [ILLUSTRATION FOR FIGURE 2 OMITTED].
One explanation for this pattern is that clipped plants may experience an increase in within-plant pollinator movement and associated geitonogamous
pollen transfer (see Juenger and Bergelson  for additional alternative hypotheses).
Pollinator behaviour often varies in different sized plants, with relatively more geitonogamous
pollinations in larger plants (Dudash 1991).
For those orchids in which small [delta] values lead to geitonogamous
pollination, the number of pollinaria removed may not be an accurate estimate of pollen export.
Among these genera, the mating system is known only for Bidens, where Sun and Ganders (1988) estimated that selfing occurred at a rate of 43% averaged over 15 populations of 11 species, due primarily to geitonogamous
matings of hermaphrodites.
A likely consequence of this foraging behavior is a high level of self-pollination (whether autogamous or geitonogamous
, Gomez and Zamora 1996), a common feature noted for other mass-flowering species (Augspurger 1980, Stephenson 1982, Frankie and Haber 1983, Harder and Barrett 1995, Snow et al.
With synchronous flowering and dichogamy (Lloyd and Webb 1986) or temporal dioecism (Cruden and Hermann-Parker 1977), there is no overlap of pollen presentation and stigma receptivity among flowers within a plant, and hence no geitonogamous
Partial selling may also be a nonadaptive consequence of geitonogamous
pollen transfer, which may commonly occur in mass-flowering species like D.
Finally, the herbivore's effect on pollinator behavior may alter plant reproductive success by changing the selfing rate, either by increasing autogamous pollen transfer or decreasing geitonogamous