Ulmus sp.

Smith, MacKenzie A., Greenwalt, Dale E. & Manchester, Steven R., 2023, Diverse Fruits And Seeds Of The Mid-Eocene Kishenehn Formation, Northwestern Montana, Usa, And Their Implications For Biogeography, Fossil Imprint 79 (1), pp. 37-88 : 55

Ulmus sp. L1

Text-fig. 7i

M a t e r i a l. DMNH EPI.48205.

L o c a l i t y. Disbrow Creek.

D e s c r i p t i o n. Leaf elliptical, 4.4 cm long, 2.0 cm wide; petiole 0.4 cm long, 0.1 cm wide; base asymmetrical, apex not preserved; venation pinnate, secondaries craspedodromous, excurrent and arising at 41°, curving apically near the margin into the apex of the tooth, secondary pair spaced every ca. 2.7 mm apart; intersecondary veins present; teeth one order, regularly spaced, proximal flank convex and distal flank straight or concave.

R e m a r k s. This leaf can be placed confidently in the Ulmaceae because of its asymmetrical lamina, short, stout petiole, pinnate venation and marginal teeth with submedial enervation. Leaves with one tooth per secondary vein occur in Zelkova , Hemiptelea , Cedrelospermum , and occasionally Ulmus . Although most species of Ulmus have compound teeth with multiple teeth per secondary vein, simple teeth, organized one per secondary vein, occur in some species of Ulmus , as confirmed for Ulmus okanaganensis (where such leaves are attached to twigs bearing the diagnostic fruits). We infer that this leaf represents Ulmus , by its association with the fruit described above.

Figures

Text-fig. 7. a: USNM PAL 722490 cf. Myriophyllum fruit. Scale bar 1mm. b: USNM PAL 624027 three-valved Populus sp. capsule on pedicel. Scale bar 3mm. c: USNM PAL 717328 Deviacer wolfei samara. Scale bar 5mm. d: USNM PAL 621987 Fabaceae sp. 1 Legume fruit showing persistent style. Scale bar 2mm. e: USNM PAL 625803 Fabaceae sp. 2 fruit. Scale bar 5mm. f: USNM PAL 620816 Agrimonia sp. fruit. Scale bar 3mm. g: Modern Agrimonia pubescens fruit (image by Tracey Slotta, United States Department of Agriculture National Resource Conservation Service Plants Database). h: USNM PAL 621976 Ulmus sp. F1 fruit showing two persistent styles. Scale bar 2mm. i: DMNH EPI.48205 Ulmus sp. L1 leaf. Scale bar 1cm. j: UF 19652-86483 endocarp of Celtis sp. k: UF 19652-86484 Endocarps of Celtis sp.