In botany, a spiral is an arrangement of sepals, petals, leaves, stipulations or branches that radiate from a single point and surround or wrap around the stem. A whorl consists of at least three elements; A pair of opposing leaves is not called a spiral.
The morphology of most Angiosperm flowers is based on four verticilos:
1. the chalice, a spiral of sepals at the base, above which are
2. the corolla, a spiral of petals,
3. the androcius, a spiral of stamens (each of which comprises a filament and an anther), and
4. the gineceo, a spiral of the feminine parts of a flower: stigma, style and ovary.
A flower that lacks any of these floral structures is said to be incomplete or imperfect. Not all flowers consist of spirals, since the parts can be spiraled, as in Magnoliaceae.
For leaves to grow in whorls is quite unusual except in plant species with very short inter-nodes. However, it occurs in some trees as Brabejum stellatifolium and other Proteaceae, as some species of Banksia. In examples as illustrated, attestations entrenudos within catchments alternate with long internodes between whorls.