Anthurium amnicola has a somatic chromosome number of 30, the most common number in the genus. There are two pairs of large metacentric chromosomes, three pairs of fairly large acrocentric chromosomes, one pair of satellite chromosomes, and nine pairs of either metacentric or acrocentric small chromosomes. At prometaphase I of meiosis in pollen mother cells 15 bivalents were formed. A. amnicola hybridized readily with A. andraeanum, A. lindenianum, and A. formosum in the section Calomystrium as well as the cultivars 'Calypso' and 'Trinidad' of unknown origin. All interspecific hybrids examined meiotically formed 15 pairs, and all except two hybrids with A. lindenianum showed more than 90% normal tetrad formation. Pollen stainability of these hybrids with acetocarmine ranged from 3.3% to 27.8%, compared to 87.5% in A. amnicola. It is concluded that A. amnicola is genetically closely related to species in section Calomystrium.