Lycophyta (division)

Small plant distinguished by the club-like shape of its upright fertile spore-cases and the very small microphylls, a kind of leaf that arose and evolved independently from the leaves of other vascular plants; the microphyll has only a single unbranched strand of vascular tissue. While this division is a small and inconspicuous group of plants today, in the Carboniferous some lycophytes were forest-forming trees more than 35 meters tall. Lycophytes are the oldest extant group of vascular plants, and dominated major habitats for 40 million years.