Developmental anatomy of Cyperus laxus (non-Nranz) and Fimbristylis dichotoma (Kranz) (Cyperaceae, Poales) and tissue continuity.

The Cyperaceae species are present in different ecosystems and constitute the herbaceous extract. Of the approximately 5,500 species of the family; a third has Kranz anatomy, representing an important characteristic of the taxonomy and phylogeny of the group. In Cyperus laxus L. (non-Kranz) and Fimbristylis dichotoma Vahl (Kranz), development begins with germination that is marked by the emergence of the coleoptiles, followed by the primary root, which is ephemeral. The rhizome originates from the mesocotyl and it promotes the vascular connection between the roots, leaves and scapes. The continuity of the tissues is evidenced by the presence of an endodermis and pericycle in all vegetative organs. Leaves and scapes differ between the two species by the arrangement of mesophyll cells, which is regular in Cyperus laxus (non-Kranz) and arranged radially in Fimbristylis dichotoma (Kranz). Also differ in the number of bundles sheaths: two in Cyperus laxus (non-Kranz) and three in Fimbristylis dichotoma (Kranz). The outer bundle sheath in both species constitutes the endodermis, and the inner sheath in Cyperus laxus and the middle and inner sheaths in Fimbristylis dichotoma constitute the pericycle.