Life History of the Orchid Cyrtopodium Broadwayi

Abstract

This study has revealed that Cyrtopodium broadwayi in its natural habitat grows for about nine months beginning approximately with the beginning of the dry season at year's end and ending with the "petit careme " (little dry season) in October. It flowers mainly in the dry season with a peak in the period February - March. However, a few plants begin growing at midyear and may flower then. This explains the seemingly strange flowering behaviour recorded by Schultes (1967). Our studies have shown, too, that the flowering period is more extensive than that recorded in the Flora. But this pattern of growth and flowering presents a paradox. Either the plants respond to the same stimulus at both periods of the year when to us conditions seem so different that a similarity is hard to imagine, or they respond to different stimuli which would be a very unusual state of affairs. If we reject external stimuli and opt for an explanation based on internal ones, we are faced with the question why do the plants not begin growth and flower each with its own rhythm all through the year?