Brazil nut inflorescence

Part of the inflorescence of a Brazil nut tree (Bertholletia excelsa) based on Mori et al. 17503 from Amapá, Brazil. Note the calyx has two lobes, the style is geniculate, and the petals are tightly appressed against the androecium. Each of the lobes of the two-lobed calyx is formed from the postgenital fusion of three sepals. In early bud, the the calyx encloses all but an apical slit. See Tsou and Mori. 2007. Amer. J. Bot. 94(5)