Marattiales

(botany) An ancient order of ferns having massive eusporangiate sporangia in sori on the lower side of the circinate leaves.

An order (class Polypodiopsida) of primitive ferns that consists of about seven living genera and 150 species. They exist mostly in tropical regions. These large, coarse, sappy ferns usually have large, highly divided fronds. Stems of living genera (Angiopteris and Marattia) are short and bulbous, often a foot or more in diameter. Other genera have smaller, mostly horizontal, and somewhat more elongated stems. The internal vascular system (food and water conduction tissue) of the stems and fronds can be quite complex, apparently as a function of size. Marattialeans are included among the primitive ferns primarily because of the way that the sporangia (spore-bearing organs) arise from a mass of cells rather than from a single cell as in more highly evolved ferns. See also Paleobotany; Polypodiophyta.