ACROGENAe is the name applied to a division of acoty ledonous or cryptogamous plants, in which leaves are present along with vascular tissue. In the higher divisions of Acrogens,as ferns and lycopods, the tissue consists of scalari-form vessels, while in the lower divisions spiral cells are observed, which take the place of vessels. The term Acro-gen means summit-grower, that is, a plant in which the stem increases specially by the summit. This is not, however, strictly accurate.