HYENIA

a genus of small fossil shrublike plants of the order Hyeniales, class (or subdivision) Sphenopsida, known from rocks of the Devonian period (408 to 360 million years ago). Hyenia elegans has numerous upright and rarely branched shoots that arose from an underground stem; it bore whorls of narrow, forked leaves. H. vogtii is of interest because its frequent, regular, and strictly lateral mode of branching suggests a possible origin of leaves.