Abstract Detail

Paleobotany

Stockey, Ruth [1], Mindell, Randal [2], Beard, Graham [3].

A Tiffneycarpa-like fruit from the Eocene Appian Way Locality of Vancouver Island.

Sixty-two permineralized drupaceous fruits have been identified in calcium carbonate concretions from the Appian Way Locality south of Campbell River on Vancouver Island, British Columbia, Canada. Fruits, 4-15 mm in diameter and 9-28 mm long, are barrel-shaped with a woody, thick-walled endocarp and a fleshy aerenchymatous mesocarp. Individual fruits vary from round in tranverse section, to lobed, to having longitudinal ridges and furrows; and most fruits are lobed at some levels. Fruits show 6-11 locules each containing a single seed. Only one seed per fruit develops, the remainder being aborted. Near the base of the fruit the central axis shows a ring of vascular bundles that vary in number. More distally, there is also a ring of bundles at the margin of the endocarp and mesocarp. The latter appear to be on alternate radii with the locules. Additional bundles extend toward the fruit margin within the mesocarp. Locules are vertically elongate up to 6 mm long and 1.3-1.5 mm wide, 2.0 mm wide in dorsiventral dimension. The locule lining is uniseriate composed of fibers 20-35 µm in diameter. The endocarp is composed mostly of sclereids with undulating margins, 33-88 (mean = 55) µm in diameter. Dehiscence is loculicidal with radial planes of dehiscence formed by smaller sclereids radiating from the central axis and bisecting each locule. The mesocarp forms a band 1.8-3.2 mm thick with two zones, an inner zone of radially elongate cells and an outer zone of isodiametric cells. The elongate cells of the inner zone are up to 275 µm long, 20-35 µm wide, and in some fruits the cells show dense simple pitting. Most of the fruits show evidence of lysigenous formation of elongate aerenchyma channels in the inner mesocarp zone, suggesting dispersal by water. Seeds are attached to the ventral margin of the locule near the apex. We compare the Appian Way fruit to those of extant Meliaceae, Euphorbiaceae, and Rutaceae and fossil seeds assigned to these families. These fruits most closely resemble those of Tiffneycarpa Manchester and Melicarya Reid & Chandler but for the first time reveal details of the soft tissues outside the endocarp.

1 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331.0, United States
2 - Botany, #3529 - 6270 University Boulevard, University Of Alberta, Vancouver, BC, V6T 1Z4, Canada
3 - Qualicum Beach Museum, Qualicum Bay, BC, Canada

Keywords:
Eocene
Tiffneycarpa
Meliaceae
Melicarya
fruits
permineralized.

Presentation Type: Oral Paper
Session: PAL4, Paleobotany IV: Paleogene Paleobotany
Location: Tucson C/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 4:15 PM
Number: PAL4003
Abstract ID:349
Candidate for Awards:None