Senecio esleri (Asteraceae), a new fireweed Journal Paper
- Author
- Webb, C.J.
- Year
- 1989
- Journal / Source
- New Zealand Journal of Botany
- Volume
- 27
- Number
- 4
- Pages
- 565-567
- Keywords
- Eryngium vesiculosum, heterophylly, leaf form, daylength, aquatic plants, New Zealand
- Summary
- Eryngium vesiculosum is a small rhizomatous, perennial umbellifer of coastal sands, lake margins, and riverbeds in New Zealand. The species is seasonally heteroph.yllous; summer l~aves are laminoid and prickly, winter leaves are hnear and fistular. This form of structural variation is classifiable as a conditional choice. Experiments using controlled conditions showed that day length cues the change ofleafform which occurs in autumn and spring, and that total immersion in water aff~cts leaf form to a lesser extent and prevents flowenng. It is suggested that summer le~ves are adapt~d to well-drained conditions, and winter leaves to inundation by water.