The reproductive biology of two species pairs was compared, one member of
which (Dryandra sessilis (Knight) Domin,
Hakea erinacea Meissner) is susceptible to severe stress
and disturbance by fire (nonsprouter) and stores few seeds in its crown, while
the other (D. lindleyana Meissner,
H. cristata R.Br.) is resilient (resprouter) and also
stores most of its seeds for some years. It was hypothesised that the
nonsprouter would have a high annual seed production associated with a suite
of attributes directed towards that end (forming a reproductive syndrome), and
that the resprouter would have the reverse properties. Over 30 attributes were
assessed, covering putative pollinators, pollinator attractants and rewards,
flower phenology, breeding system, and flower, fruit and seed production.
Dryandra sessilis produced far more seeds than
D. lindleyana, due to prolific flower production and a
high fruit : flower ratio (associated with an effective outcrossing breeding
system). Hakea erinacea produced significantly more
seeds than H. cristata, which was attributable to its
smaller fruits and exceptionally high fruit : flower ratio (associated with
highly effective selfing). The correlation of seed production and fruit :
flower ratio with susceptibility to fire was not supported by any consistent
pattern among the other reproductive attributes.