Rhizomes in Tropical Eucalypts and Their Role in Recovery From Fire Damage

Abstract

Some tropical woody perennials including three Eucalyptus species, viz. E. porrecta S. T. Blake, E. Ptychocarpa F. Muell., and E. jacobsiana Blakely, were observed to have rhizomes and rhizomatous systems. The possession of rhizomes by woody perennials has rarely been reported, and never in other eucalypts.

Further investigation of E. porrecta revealed that it occurred in varying stages of development, ranging from short aerial stems commonly less than 0.7 m high to trees varying from 1.5 to 10 m high. The short stems and trees were distributed as isolated individuals, or in clonal patches usually consisting only of short stems or one to many trees in combination with short stems. Aerial systems were correlated with fire frequency and severity. The characteristics of rhizomes and rhizomatous systems of E. porrecta are described in relation to aerial systems.

The adaptive significance of the rhizomatous systems to persistence and reproduction of the species is discussed. Vegetative spread results in a large reservoir of protected dormant buds in underground stems. This ensures persistence of the plant when subjected to frequent fire damage.