Survival, Fecundity and Growth of Wild Cucumber, Echinocystis Lobata

Abstract

(1) Survival, fecundity and growth of Echinocystis lobata (Cucurbitaceae) were studied in two populations in New York State, U.S.A. The plant is a climbing, monoecious annual of damp places which rarely occurs in the dense stands typical of other annuals. (2) Disease eradicated the plant entirely from one study site and removed much of the population from the other site before flowering occurred. (3) A life table and an age-specific fecundity schedule for the surviving population are presented. Plants are protandrous, and flower late in the life cycle. An evolutionary explanation is offered for late flowering in terms of the relationship between plant size and fecundity and the vegetative costs of fruit production. (4) The size-frequency distribution of plants developed a right-handed skew with time and showed similarities with distributions observed in populations of other species growing in quite different ecological conditions.