Abstract Detail

Paleobotany

DeVore, Melanie [1], Wheeler, Elisabeth [2], Pigg, Kathleen [3], Siggers, Jordan [4].

Wood anatomy, phenology, and leaf type correlation, is it useful for tracking seasonality in fossil floras.

Paleobotanists have addressed identifying the deciduous habit in the fossil record using both leaves and wood anatomy. Trees with ring-porous wood are always deciduous (Boura & DeFrancheschi 2007), however, species with semi-ring-porous and diffuse wood types can also be deciduous. Foliar phenology is strongly correlated with the organization of water-conducting elements in wood (Lechowicz 1984; Wang et al. 1992). Lechowicz characterized the following trends with deciduous hardwoods: (1) early-leafing species (e.g., Acer, Betula, Populus) with distinct long-shoot/short-shoot growth and diffuse-porous wood, (2) later-leafing species with diffuse-porous wood lacking shoot differentiation, and (3) late-leafing ring-porous species (Lechowicz 1984, fig. 6). In central Georgia, USA, we observed that although the genus Ulmus is often an early (mid March) leafing genus, it has ring porous wood. However, Ulmus alata leafs out later from other species from mid-March to mid-April. Quercus acutissima also leafs out early and is ring-porous. In examining the leaves of both Ulmus crassifolia and U. parvifolia and early leafing species of Quercus (Q. acutissima) we found that they had craspedodromous leaves with toothed margins. ** Pinnate veins, with open secondaries, were characters shared by early leafing, ring porous species. This observation supports Walls' (2011) finding that vein patterns, leaf functions, and phylogeny have the potential for estimating functional attributes of fossil plant species and communities. We looked at the percentage of toothed, craspedodromous leaves, density of secondary veins, and the presence of numerous open secondary veins, in the latest early Eocene Republic Flora and found they accounted for more than 50% of the woody dicot species we recognize in the flora. This would be suspected for an alpine flora based on Walls' model. This seems to suggest that leaf architecture characters, along with wood anatomy, can provide a valuable tool for documenting the deciduous habit in the fossil record

1 - Georgia College & State University, Biological And Environmental Sciences, Campus Box 081, Milledgeville, GA, 31061, United States
2 - 710 Dixie Trail, Raleigh, NC, 27607, United States
3 - Arizona State University, School Of Life Sciences, PO Box 874501, Tempe, AZ, 85287, United States
4 - Georgia College and State University, Milledgeville, GA, 31061, USA

Keywords:
Eocene Republic Flora
deciduousness
wood
phenology
Leaf Architecture.

Presentation Type: Poster
Session: P3, Paleobotany Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PB004
Abstract ID:947
Candidate for Awards:None