• Korean Journal of Plant Taxonomy
• /
• v.31 no.4
• /
• pp.311-319
• /
• 2001

In order to evaluate taxonomic status of Latcuca hallaisanensis H. $L{\acute{e}}v$., an endemic species of the Jeju-do Island, we investigated fruit wall structure and chromosome morphology. The fruit wall structure had 10-11 obtuse costae in the transverse section. The costa was wholly occupied by libriform fiber cells, and the underlying fibersclereid tissue was only one to three cells layers thick. Also, the intercosta lacked fiber-sclereid layers. Somatic chromosome numbers and karyotype of Latcuca hallaisanensis were recorded for the first time. This diploid species (2n=10) with the same basic number of x=5 has the total chromosome length $23.3{\mu}m$ and the length of each chromosome falls in $1.9{\mu}m-2.9{\mu}m$. It possess the karyotype complement i.e., 3sm+2st and a characteristic chromosome pair (No. 1 and 2) with a secondary constriction at the distal portion of the short arms. The overall similarity in external morphology (involucre, achene etc), chromosome morphology as well as in fruit wall anatomy between Lactuca hallaisanensis and Crepidiastrum s. lat. clearly indicated that this species should be treated as Crepidiastrum, rather than Lactuca.