Taxonomy of the Babassu Complex (Orbignya spp.: Palmae)

Abstract

The taxonomic identity of the economically important group of palms known in Brazil as (Orbignya spp.) has been a source of confusion for well over a century, largely due to a proliferation of species described from incomplete specimens obtained at a limited number of sites. To resolve this confusion, we collected complete material over a wide part of babassu's distribution in Brazil and Bolivia; additional material was obtained from Surinam. Based on the literature, biological data obtained in the field, and detailed morphological comparisons of specimens in the laboratory, we conclude that the complex is comprised of two principal species, each with a pronounced tendency to hybridize. The most widely distributed species is Orbignya phalerata C. Martius, originally described from Bolivia, which is identical to a number of subsequently described (and consequently synonymous) species from Brazil. A second species, 0. oleifera Burret, appears to be restricted to the Sao Francisco River Basin in Minas Gerais, Brazil. The wide geographic range of this complex and its propensity to hybridize have probably contributed to its high morphological variability. We suspect that this variability will prove to be a common theme in certain groups of palms currently thought to be comprised of many species. Over widespread areas of Brazil, palms known locally as babaqu (spelled babassu in English) occur in pure stands that virtually blanket the landscape (fig. 1). Babassu stands form spontaneously on sites where the original forest cover has been cleared (Anderson and Anderson 1983). The total area of these stands in Brazil was recently estimated at 196,370 km2 (STI 1979), roughly equivalent to the U.S. state of South Dakota. Babassu palms are an important source of vegetable oil in Brazil. In 1980,250,951 metric tons of oil-rich kernels were sold to oil pressing facilities throughout the country (IBGE 1983); the manual extraction of these kernels is a source of livelihood for hundreds of thousands of rural families (May et al. 1985). In addition to vegetable oil, fruits provide a host of market and subsistence products, including flour, alcohol, charcoal, coke, tar, combustible gases, etc. (fig. 2). Despite its ecological and economic importance, the taxonomy of has been a source of confusion since it was first described well over a century ago. The confusion begins on the generic level. Although is generally assigned to the Cocoeae (Attaleinae) genus Orbignya (currently considered to comprise ca. 18 species), the status of this and the four other genera in the Attaleinae (sensu Dransfield and Uhl 1986) has been questioned by Wessels Boer (1965). These genera are distinguished solely on the basis of staminate flower morphology. No correlation with other characters has been observed, and staminate flower morphology spans a separation based on other characters such as endocarp pores. Lines between genera in the Attalea alliance are further blurred by collections of intermediate flower types, which have prompted the description of two new genera; one of these, Markleya, was described by Bondar (1957) as a possible intergeneric hybrid involving babassu. A classification based solely on staminate flower morphology is of little use in the field, as most species flower for a brief period of time. Thus it is no surprise that the species of are often confused with other species or even genera, notably Attalea. Oil palms commercially referred to as include Orbignya agrestis (Barb. Rodr.) Burret in the Brazilian state of Para, Attalea oleifera Barb. Rodr. in the states of Goias and Minas Gerais, A. geraensis Barb. Rodr. in Minas Gerais, and A. pindobassu Bondar in the state of Bahia (Markley 1971). Even botanists are not immune to generic confusion when dealing with the Attalea alliance. For example,