Cupressoideae

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 : 42

Cupressoideae 3

Text-fig. 2m

M a t e r i a l. USNM PAL 620184.

L o c a l i t y. Park.

D e s c r i p t i o n. Scaly leaf axis measuring 6.4 mm long, 1.8 mm wide at lateral leaf widest point; leaves 2.1 mm long, 1.1 mm wide; distance between facial leaf apices 2.6 mm; facial leaf apices do not cover subsequent lateral leaf junction; leaf apices rounded and acute 68°.

R e m a r k s. Cupressoideae 3 differs from Cupressoideae 2 by having longer leaves (2.1 mm vs. 1.4 mm), that are nonkeeled and acute apices. Cupressoideae 1 might be equivalent to Cupressoideae 3, with their different appearance due to abscission of leaves in the former. Abscission can occur in genera like Chamaecyparis such that the facial leaves can either cover or not cover the junction of the subsequent lateral leaves ( Kotyk et al. 2003). Cupressoideae 3 differs from Cupressoideae 4 by having appressed leaf junctions instead of leaf junctions that flare outward. This fossil cannot be placed confidently in a modern genus.

Figures

Text-fig. 2. Equisetum and conifers from the Kishenehn Formation. a: USNM PAL 620616 Equisetum sp. stem apex. Scale bar 3mm. b: USNM PAL 622297 Coniferae 1. Scale bar 5mm. c: USNM PAL 622081 Coniferae 2. Scale bar 2mm. d: USNM PAL 717666 cf. Metasequoia sp. seed. Scale bar 1mm. e: USNM PAL 622101 cf. Metasequoia sp. seed. Scale bar 1mm. f: USNM PAL 776571 Metasequoia sp. twig showing opposite leaves. Scale bar 10mm g: USNM PAL 776572 Metasequoia sp. twigs. Scale bar 10 mm. h: USNM PAL 621667 Juniperus sp. leafy twig. Scale bar 5mm. i: USNM PAL 722223 Juniperus sp. twig. Scale bar 2mm. Scale bar 3mm. j: USNM PAL 623467 unidentified Cupressoideae 1. Scale bar 3mm. k: USNM PAL 620274 unidentified Cupressoidae 2 leaves. l: USNM PAL 620087 unidentified Cupressoideae 2. Scale bar 1mm. m: USNM PAL 620184 unidentified Cupresseoideae 3 shoot. Scale bar 2mm. n: USNM PAL 621863 Cupressoideae 4 leafy twig. Scale bar 5mm.