Plant Biology ISSN 1435-8603 RESEARCH PAPER Reproductive biology and pollination mechanisms of Epidendrum secundum (Orchidaceae). Floral variation: a consequence of natural hybridization? E. R. Pansarin & M. C. E. Amaral Departamento de Botaˆ nica, Instituto de Biologia, Universidade Estadual de Campinas, Sa˜ o Paulo, Brazil Keywords ABSTRACT Epidendroideae; Epidendrum; Laeliinae; Orchidaceae; pollination; reproductive biology. The phenology, flower morphology, pollination mechanism and reproductive biology of Epidendrum secundum were studied in a semi-deciduous forest at Correspondence the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both E. R. Pansarin, Departamento de Biologia natural reserves in the State of Sa˜o Paulo, southeastern Brazil. E. secundum Aplicada, Universidade Estadual Paulista, flowers all year round, with a flowering peak between September and FCAV, 14884-900, Jaboticabal, SP, Brazil. January. This species is either a lithophytic or terrestrial herb in the SJ, E-mail:
[email protected] whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides. E. secundum is pollinated by several species of diurnal Lepidoptera at both Editor study sites. In Picinguaba, where E. secundum is sympatric with E. fulgens M. Ayasse and both share the same pollinators, pollen transference between these two species was recorded. E. secundum is self-compatible but pollinator-depen- Received: 25 March 2007; Accepted: 22 May dent. It is inter-compatible with E. fulgens, producing fertile seeds. In con- 2007 trast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present doi:10.1111/j.1438-8677.2007.00025.x flowers with characteristics in-between both sympatric species, suggesting that natural hybridization occasionally occurs.