Intraspecific chromosome variation in Zamia (Zamiaceae, Cycadales)

Abstract

Intraspecific chromosome variation in three species of Zamia (Zamiaceae, Cycadales) from Mexico and Belize is reported. Zamia fischeri has 2n = 16 and 18, Z. picta has 2n = 21 and 22, and Zamia sp. nov. has 2n = 22 and 26. All cytotypes have two submetacentric and two acrocentric chromosomes but differ in number of metacentric and telocentric chromosomes in a one-to-two ratio. Comparative analysis of karyological, morphological, distributional and ecological features in these three and allied species shows that centric fission rather than centric fusion is most likely responsible for karyotypic variation in the three species. © 1991 Taylor & Francis Group, LLC.