genus of fossil plants based upon impressions of palmlike leaves from the Triassic Period (251 to 199.6 million years ago) found in rocks from Colorado. It may be among the earliest of angiosperms (angiosperm), or flowering plants. The elliptic leaves were pleated, up to 40 cm (16 inches) long and 25 cm (10 inches) wide, and borne at the tip of a tapering stem.