Some components of the essential oil from the leaves of Siparuna guianenis (Monimiaceae) were identified and determined in the steam-volatile extract. The major constituents are curzerenone (26%) and curzerenone types (42%), as well as myristicin or an isomer (8%). This represents the first chemical study of the composition of Siparuna guianensis oil.

This study involves a taxonomic treatment of the species of Spiaruna (Monimiaceae) found in Panama. Included are keys, descriptions, distributions, and photographs. Currently there are 16 species of Siparuna in Panama. Six of these are described as new species previously unknown. A taxonomic interpretation of these taxa were based upon extensive field study and analysis of herbarium specimens. Floral characters proved to be very important taxonomically, especially when viewed by the light and scanning electron microscopes.

The dioecious species, Siparuna pauciflora, S. nicaraguensis, and S. vinosa occur sympatrically in the premontane wet forests of Panama. The two tree species, S. pauciflora and S. nicaraguensis, have seasonal patterns of flowering and fruiting with flowering coincident with the end of the dry season and fruiting peak at the beginning of the rainy season. Siparuna vinosa, a shrub, is seasonal in both flowering and fruiting. No patterns of spatial segregation were observed in S. pauciflora or S. nicaraguensis; however, S. vinosa tended to be aggregated. Plants such as S. vinosa with few flowers may increase the probability of seed set by flowering over a longer period of time and also occurring in aggregate. A longer fruiting period also increases the probability of seed dispersal.