Criteria for the Monocotyledons

Abstract

We have accepted here the hypothesis that the monocotyledons are monophyletic on the basis of two character conditions: (1) they have a single cotyledon, or according to an alternative interpretation no cotyledon at all, whereas the dicotyledons have two (other numbers such as 0, 1, 3 or more are obviously secondarily derived); (2) their sieve tube plastids, where investigated, always accumulate protein in the form of triangular bodies (Fig. 1), a condition known in the dicotyledons in only two genera (Saruma and Asarum) in Aristolochiaceae.