Abstract:

According to the karyotypic  data the present author proposes two evolutio-

nary lines, A and L (Fig. 1), in Taxodiaceae (Exclud. Sciadopitys). The former is characteri-

zed by a relatively rapid increase of the mean arm ratio but a relatively slow rise of the ratio of

the longest chromosome to the shortest one and it is composed of  Cryptomeria, Glyptostrobus,

Taxodium and Taiwania, which advance from primitive to progressive in the order. The latter

is characterized by, on the contrary, a relatively slow increase of mean arm ratio and a relative-

ly rapid rise of the ratio of chromosome size and it comprises   Metasequoia, Sequoiadendron,

Sequoia and Cunninghamia (probably Athrotaxis also), which advance in the order. The infer-

ence is supported by the data from morphology, anatomy, embryology and so on.

Key words  Taxodiaceae; Karyotype; Evolutionary line