The type form is the Caucasian species roseum of botanists, hardy perennial, with finely cut leaves and large flower heads, having a ray of deep rosecoloured ligulate florets surrounding the yellow centre or disk.
For these reasons no attempt has been made to arrange the orders in larger divisions, since such a division as that of the ligulate and eligulate forms, while convenient for practical purposes, may not express the phylogeny of the group. The Psilotaceae, formerly included in the Lycopodiales, have been described separately owing to their resemblance to the Sphenophyllales.
- Irregular gamopetalous ligulate flower of Ragwort (Senecio).
When a tubular corolla is split in such a way as to form a strap-like process on one side with several tooth-like projections at its apex, it becomes ligulate or strap-shaped (fig.