Diploid chromosome numbers are presented for 31 species of Passiflora
in subg. Plectostemma (sect. Cieca, Pseudodysosmia, Xerogona, Decaloba
), Passiflora, Distephana, Tacsonia, and a few species of uncertain al
liance. All but one of the counts are of neotropical taxa and the majo
rity are the first reported for each. We remove P. sanguinolenta from
subg. Psilanthus and transfer it to subg. Plectostemma, sect. Xerogona
, based on morphological and karyotypic evidence. There are two basic
numbers that are widespread in Passiflora: the relatively symmetrical
and large karyotype of x = 9, which is reported for subg. Passiflora,
Distephana, and Tacsonia; and the more asymmetrical and smaller karyot
ype of x = 6, counted here for subg. Plectostemma.