the number of chromosomes characteristic of a species —note the number of chromosome sets associated with this number must also be specified; thus in Pinus the chromosome number may be expressed as n = 12 or as 2n = 24, depending on whether the reference is to haploid sex cells or normal diploid vegetative cells —see aneuploid, gamete, hexaploid, karyotype, polyploid This definition last updated 07/18/2008