The tribe Sicyeae consists of approximately 150 species in 16 genera including the large, widespread genera Sicyos, Echinopepon, and Cyclanthera, as well as several economically important species. The Sicyeae were described by Jeffrey based on the presence of nectaries derived from trichome hairs on the hypanthium. The tribe is further subdivided into two subtribes, Sicyinae and Cyclantherinae, based on pollen and ovule characters. Recent molecular sequence data from two loci have shown the Sicyeae to be a strongly-supported natural group. However, relationships within the tribe were less clear. The subtribes were not found to be monophyletic, nor were the genera Sicyos, Sechiopsis, Sechium and Cyclanthera. Some of these results conflicted with earlier morphological studies of the subtribe Sicyinae. The objectives of this study were to expand morphological sampling to include all genera in the Sicyeae and combine these data with the molecular sequence data in a cladistic analysis. Preliminary results indicate that many relationships in the Sicyeae are better resolved when the datasets are combined. Early evidence suggests that subtribe Sicyinae is monophyletic and nested within the Cyclantherinae. The genus Sechium was previously recognized as two or three distinct genera and present data support the paraphyletic nature of the group. The monophyly and paraphyly of other genera within the tribe and the homoplasy of key morphological characters indicated by this study will be discussed.

Key words: Cucurbitaceae, Mexico, morphological evolution, nectary, Sechium