Abstract Detail


Walker, Zane [1], Rothwell, Gar [2], Stockey, Ruth [3].

A permineralized osmundaceous fern sporeling from the Lower Cretaceous of western Canada.

A single anatomically preserved fern sporeling has been discovered within a calcareous marine concretion from the Lower Cretaceous Apple Bay locality on Vancouver Island, British Columbia, Canada. ­The specimen was studied from serial transverse sections prepared by the cellulose acetate peel technique. The rhizome ranges 1.0 – 1.3 mm in diameter, has a sclerenchymatous pith, dictyoxylic stelar architecture, and sclerenchymatous outer cortex. Cauline xylem forms a nearly complete solenostele toward the base of the specimen, but it is dissected into discrete bundles distally. As is characteristic of osmundaceous cauline xylem, some bundles have no protoxylem while others have a single protoxylem strand. Fronds diverge in a helical phyllotaxis, range up to 1.2 mm in greatest dimension, have a C-shaped trace, and outer cortex of uniformly thickened sclerotic cells. Within the outer cortex there are two lateral sclerotic strands, and a sclerotic strand adaxial to the trace. Several diarch and apparently monarch roots, each with a sclerenchymatous outer cortex, also diverge from the rhizome. Together with Todea tidwellii (rhizome with frond bases) and Osmunda vancouverensis (fertile frond segments with sporangia and spores), this sporeling reveals that osmundaceous ferns were well represented in the Apple Bay assemblage. Several features of the sporeling conform to those of T. tidwellii, but consistent differences in the distribution of sclerenchyma in the frond bases suggest that it represents a distinct species.

1 - Oregon State University, Botany and Plant Pathology, Cordley Hall, Corvallis, OR, 97331, USA
2 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, United States
3 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331.0, United States


Presentation Type: Oral Paper
Number: PB1004
Abstract ID:72
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award

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