studies with the Araceae have been fairly extensive for a tropical
family, perhaps owing to the fact that the family is so widely cultivated.
The most extensive reviews of chromosomal variation in the family
are those by Marchant (1970, 1971a, 1971b, 1972). Somatic chromosome
counts range from 2n = 22 to 2n = 140 for the family, and there
is considerable diversity in the size of chromosomes. Jones (1957)
indicates that x = 6 and 7 are the basic numbers for the family
and that others have been derived. Larsen (1969) and Hotta (1971)
believe that the most common base number is x = 7, followed by x
= 13. Jones (1957) suggests that 2n = 26, 30, and 34 are amphidiploid
numbers that arose from hybridization and doubling of diploid species.
Polyploidy appears to have played an important role in the evolution
and speciation of the family.
(1970) reported base numbers of n = 7 for those members of the Colocasioideae
which he investigated, namely Remusatia, Alocasia, Colocasia,
Xanthosoma, Caladium, and Ariopsis. Syngonium
has had counts of 2n = 24 (Pfitzer, 1957; Marchant, 1970), 2n =
26 (Marchant, 1970), 2n = 28 (Sharma, 1970), and 2n = 30 (Marchant,