Cycadophytes were the first gymnosperms. They are dioecious, with seed and pollen cones on separate plants. In pollen cones, microsporocytes undergo meiosis and develop into immature male gametophytes, called pollen grains. Wind or insects transport them to the ovule, where they germinate and grow a tube down to the egg. This marks a major evolutionary advantage – plants no longer needed a water medium to reproduce. Cycads have large colorful seeds which attract insects to disperse the pollen. Cycads have compound leaves and a thick, soft pachycaul stem, made up of storage tissue.

Back to:
Phylogenetic Tree
Gymnosperms

Geologic Timeline