Observations on biosystematic relationships of Kunzea sinclairii and on an intergeneric hybrid Kunzea sinclairii × Leptospermum scoparium

Abstract

Observations were made on the growth, morphology, cytology, flowering, pollen, flavonoid patterns, and essential oil profiles of a population of Kunzea sinclairii (Kirk) W. Harris and comparisons made with populations of K. ericoides (A. Rich.) J. Thompson, and Leptospermum scoparium J. R. et G. Forst. A hybrid, K. sinclairii × L. scoparium, was discovered in the K. sinclairii population and this is compared with the putative parent species. Consideration of the ecology and distribution of K. sinclairii on Great Barrier Island indicates it is a local endemic associated with the infertile soils derived from the Miocene volcanics that formed Mt Hobson. It is concluded that it is inappropriate to include K. sinclairii in synonymy with K. ericoides. Existence of the intergeneric hybrid, and the filament:petal ratio of K. sinclairii, introduces uncertainty about the generic boundary between Kunzea and Leptospermum. Opinions about the age of the Leptospermum suballiance in New Zealand are discussed in relation to the possible origins of K. sinclairii.

Keywords:

• Kunzea sinclairii
• Kunzea ericoides
• Leptospermum scoparium
• intergeneric hybrid
• morphological variation
• flowering
• essential oils
• flavonoids
• pollen
• cytology
• ecology
• Myrtaceae
• Great Barrier Island
• New Zealand