Abstract Detail

Paleobotanical Section

Atkinson , Brian A [1], Stockey, Ruth [2], Beard, Graham [3].

Paleogene diversification of magnoliids:  anatomically preserved lauraceous flowers from the Eocene of Vancouver Island.

Twenty anatomically preserved flowers have been recovered from the Eocene Appian Way fossil locality on Vancouver Island. The material is permineralized in calcium carbonate concretions and studied anatomically using the cellulose acetate peel technique. Flowers have delicate tissues of the tepals and stamens, and seeds are preserved inside the ovaries. These flowers are small, actinomorphic, bisexual, pedicellate, and perigynous. Each flower is trimerous with two whorls of three tepals, three whorls of fertile stamens, an inner fourth whorl of staminodes, and a single one-seeded carpel with a superior ovary. Tetrasporangiate anthers open by valvate dehiscence. The novel combination of characters that these flowers possess are: 1) perianth consisting of six undifferentiated tepals in two whorls, 2) tepals of equal lengths, bearing scattered trichomes on the inner (adaxial) surface towards the base, 3) tepals containing scattered oil bodies, 4) androecium of nine fertile stamens in three whorls and three staminodes, 5) outer two whorls of stamens introrse, and stamens of the inner third whorl extrorse, 6) stalked glandular appendages on the third whorl of stamens, 7) filaments longer than the anthers, 8) gynoecium consisting of a single glabrous carpel with a slender tri-lobed style, and 9) one anatropous seed apically attached in the ovary. This combination of characters places the flowers in Lauraceae. We compare these fossils to flowers of both living and extinct Lauraceae using a number of morphological characters with the presence of a shallow hypanthium, tepals length, stamen number, the presence of stalked glandular appendages on the third stamen whorl, number of sporangia per anther, pollen sac arrangement, length of filaments, presence of sessile, triangular staminodes, and distribution of trichomes, being the most important for distinguishing this as a new taxon of Lauraceae, most similar to the fossil Neusenia tetrasporangiata from the Late Cretaceous of North Carolina. The new Appian Way flowers are more than twice the size of those of Neusenia and differ in a number of characters. The novel combination of floral characters in the Appian Way specimens increases our knowledge of lauraceous diversity during the Eocene. At present, understanding the phylogeny of this family is complicated by ambiguities of relationships that result from incomplete knowledge of both the morphology and genetics of living species. As more extinct species of this family are found and described, the fossil record promises to help clarify relationships within Lauraceae.

1 - Oregon State University, Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97330, USA
2 - Oregon State University , Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, USA
3 - Qualicum Beach Museum, 587 Beach Road, Qualicum Beach, British Columbia , V9K 1K7, Canada

Keywords:
Lauraceae
fossil flowers
Eocene.

Presentation Type: Oral Paper:Papers for Sections
Session: 8
Location: Whitewater/Grove
Date: Monday, July 28th, 2014
Time: 11:30 AM
Number: 8012
Abstract ID:277
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award