 Some species, such as the Uruguayan Hippeastrum petiolatum, are sterile and unable to produce seeds. H. petiolatum is a sterile triploid that reproduces asexually, producing many bulbils around the mother bulb. These are light, and easily carried on the surface of water ensuring distribution of the species during the rainy season. Other species such as Hippeastrum reticulatum are self-pollinating, reproducing by distributing seed. Although this does not guarantee genetic diversity in natural populations, it is widely used by colonising species. These two examples are not however typical of the genus, which commonly reproduces through allogamy. One mechanism that limits self-pollination is that of self-incompatibility by which seeds are only produced by pollination from other plants. Furthermore, the plant generally releases its pollen about two days before its stigma is receptive, making cross-pollination more likely. Pollinators include Humming birds in subtropical areas, and moths.
