Clonal strategies of a woody weed: Melia azedarach

Melia azedarach L., a weedy tree that typically reproduces by seeds, may ex hibit clonal growth following disturbance (e.g. fire, herbivory, animal inj ury). A dynamic and holistic study (sensu Halle et al., 1978) was carried o ut in order to determine the architecture and the vegetative growth strateg ies, in plants collected from undisturbed and disturbed areas in the 'El Pa lmar' National Park. The architectural and morphological observations can b e summarized as follows: (a) Tree architecture is determined by a monopodia l trunk that produces tiers of orthotropic monopodial branches. (b) The roo t system consists of a tap root with woody primary lateral roots that exhib it plagiotropic growth and are typically found within the first few centime ters (ca. 4 cm) of the soil profile. (c) Root buds were produced in all (fi re treated and control) plagiotropic root cuts when incubated under control led conditions. Root suckers developed from the differentiation of parenchy matous cells produced by meristematic activity in the cambial zone. The eco logical implications of vegetative reproduction on the invasive capacity of this species are discussed.