Pourquoi les Monocotylédones? Une introduction pour une clé

Abstract

The Monocots are short of secondary permanent tissues: the loss of cambium makes the ramifications of the vegetative axis mechanically difficult. This loss explains the monocotyledonous charactereristics as the lack of woody structure, the parallel-veined leaves, the replacement of primary root by adventitious roots, the mode of propagation like sympodic types present in perennial bulbs and rhizomes. The presence at the embryo level of only one cotyledon is also the result of the non-branching seedling. The low percentage of epigeal germination is explainable by the fact the seed leaf acquires no chlorophyll and is limited to a sucking function. In another connection, the absence of cork renders the aerial axis frost-tender and confines many taxons to warm areas.