Stockey, Ruth A. , Rankin, Brian D. .
Fruits of Icacinaceae from the Eocene of British Columbia.
Eighteen permineralized icacinaceous fruits have been identified in the calcareous nodules from the Eocene Appian Way Locality on Vancouver Island. Specimens were studied using the cellulose acetate peel technique. At least three fruit types of what have been referred to as Palaeophytocrene are known from this site. Fruits are drupes with thin exocarp and mesocarp and a distinctly pitted endocarp with "tubercles". Endocarps are unilocular, bilaterally symmetrical with straight-walled (cylindrical) to conical protrusions into the locule cavity. The outer layer of the endocarp in all fruits is composed of thick-walled interlocking digitate sclereids. The largest fruits are 20 X 12 mm with protruding tubercle rims and an endocarp with four distinct layers, the inner one of which is papillate. The smaller fruits are 6 X 6 mm with a much thinner three-layered endocarp, also with a papillate inner layer. Intermediate sized fruits 4 mm thick and 10 mm wide, have a two-layered endocarp, the inner one of which is papillate. The intermediate-sized Appian Way fruits are most similar to P. pseudopersica Scott emend. Manchester while the other two fruits differ from previously described taxa. A reexamination of Palaeophytocrene specimens from North America suggests that anatomical characters are extremely important when designating species. A reassessment of the genus is needed since the type specimen, P. foveolata from the London Clay Flora differs from subsequently described species in some important characters, including the absence of papillae in the locule cavity. The Appian Way fruits are assigned to Icacinaceae s.s., and appear most similar to those of the Icacina group, in particular, the clade that contains Miquelia, Phytocrene, Polycephalium, and Chlamydocarya.
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1 - University of Alberta, Department of Biological Sciences, Biological Sciences Centre, Cw 405, Edmonton, Alberta, T6G 2E9, Canada
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 4:00 PM