Growth pattern and seasonal behavior of buds of Colliguaya odorifera, a shrub from the Chilean mediterranean vegetation

Abstract

Colliguaya odorifera Mol., an euphorbian shrub, grows among the sclerophyllous scrub of central Chile. The growth pattern and seasonal behavior of the floral and vegetative buds are analyzed, with special reference to the climatic conditions (cool humid winters and dry hot summers). Observations were conducted on marked twigs and in sections of embedded material.The branching system is of a Y-shaped sympodial type. The growth season of C. odorifera extends from early winter to the beginning of summer. When the dry season starts, the vegetative apical meristem is converted into a floral bud, and in the leaf axils partly predetermined, unprotected vegetative buds develop. Both types of buds remain dormant during the drought period. Soon after the first winter rains begin, activity is resumed: the preformed flowers and leaf buds unfold and grow, and a few more leaf pairs develop during the current year. Thus, buds are influenced partially by the climate of the previous and of the next year.