Plants have male flowers or female flowers only.

This is not always easy to detect, but a pointer to it is the presence of bushes with fruits and bushes without any fruits within a population. The number of bushes is usually more or less equal.

Bushes with fruits should be investigated to see whether they are producing pollen. Consistently empty or sterile anthers indicate that the flower is functionally female.

Bushes without fruits in such situations are usually prolific producers of pollen and this should be obvious on the pollen presenter. However the presence of pollen and the absence of fruits on a bush is still only a pointer to the plant being male - it could still be bisexual - and it would be necessary to check the ovary for the formation of ovules to confirm whether the flower is male or bisexual.

The only known species to have male and female flowers in Hakea are Hakea epiglottis and Hakea megadenia, both from Tasmania.