Karyotype Alteration and Phylogeny, VI

Karyotype analysis in Palmae

Abstract

The karyotypes of twenty-five genera including thirty species in the Palmae were analyzed from the view point of karyotype alteration (cf. Tab. 1). Various basic numbers in Palmae seem to be originated from the eight chromosome type, that is, 8→16→18→19, but an exact phylogenetic line can not be drawn simply by the basic number or karyotype.
Four karyotypical lines, Liliaceae→Agavaceae→Palmae, are presented by the writer's observation: 1) Eucomis, Hosta→Yucca-Agave, 2) Dianella →Phormium→Cocos, 3) Ophiopogon→Nolina→Trsthrinax, 4) Dracaena→Phoenix, Livistona, Sabal and Oredoxa (cf. p. 183). In short the writer clearly ascertained the phylogenetic affinity between Agavaceae and Palmae. This conclusion supports th-e HUTCHINSON'S opinion and unfavours ENGLER's system of monocotyledons. Here the writer reminds a dynamic system of late Professor HAYATA.
Although the karyotype seems to be more essential and changelesss characteristics than the other external morphology, the so-called karyotype or chromosome morphology is also conditioned by ecological environments as well as the other phenotypes. Some karyotypical characters in the tropical plants are suggested here, that is, chromosome sizes and polyploidy with special reference to gigas forms and winter hardiness.
Acknowledgment. In conclusion the writer wishes to express his sincere thanks to Professor SINOTÔ for his kind advice and valuable criticism throughout the course of the work. Thanks are also due to Professor HONDA of the Tokyo Imperial University and to Professor NAMIKAWA of the Kyoto Imperial University for granting the use of the materials.