Internodal Meristems of Monocotyledons: Further Studies and a General Taxonomic Summary

The occurrence of uninterrupted (UM) and intercalary (IM) meristems in the internodes of vegetative and/ or reproductive axes is reported for 90 species in 34 familie of monocotyledons. Meristem type was determined by measuring regions of surface elongation and cell division in developing internodes. Many aquatic and predominantly tropical families are included. These new data and previously published information are presented in a summary of 45 families in 19 orders of monocotyledons (sensu Takhtajan, 1969). The distribution of UM's and IM's is about equal among families and orders. Phylogenetic trends are not apparent in the distribution. Generally, UM's tend to predominate in vegetative internodes, and IM's tend to predominate in reproductive internodes.