Lycophytes

Wood, dichotomy, sexed sporangia

Lycophytes appeared from the end of Silurian (circa 410 Ma), first in a small-sized, prostrate form, then as arborescent (tree-like) forms with dichotomous stems (i.e. divided in two equal parts). Some, like the lepidodendrons and sigillaria, could reach heights of up to 40 meters. When the rudimentary leaves fell off they left behind scale-like scars on the stem. The reproductive structures, known as strobili (compact cones), bore sexed sporangia.

This group still exists today in the form of lycopodiales, selaginella and isoetes, all of which are of modest size.