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 4

Text-fig. 2n

M a t e r i a l. USNM PAL 621863.

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

D e s c r i p t i o n. Scaly leaf axis measuring 17.3 mm long and 1.0 mm wide; branchlets opposite; leaves decussate, leaves triangular measuring 1.3 mm long with a pointed acute apex measuring between 59.0 and 88.5°; distance between apices on facial leaves 2.6–2.9 mm; apex of facial leaf covers junction of subsequent lateral leaves or may be below junction; lateral leaves separate on facial surface before angling outward.

R e m a r k s. Cupressoideae 4 differs from Cupressoideae 1 and 2 by having longer leaves with pointed, rather than rounded apices and having longer internodes. Cupressaceae 4 differs from Cupressaceae 3 by having leaf junctions that flare outward instead of being appressed to the stem. The lateral leaves are not proportionally long enough to match those of Tetraclinis MAST. ( Kvaček et al. 2000) and the facial leaves are more prominent than those of Fokienia A. HENRY et H.H. THOMAS ( McIver 1992) . Mesocyparis MCIVER et BASINGER has opposite instead of alternate branching ( McIver et Basinger 1987, Kodrul et al. 2006). Alternate branching cupressaceous conifers including Thuja , Chamaecyparis and Platycladus SPACH have lateral leaf apices that can be adpressed to the side and are indistinguishable from one another ( McIver and Basinger 1987, Wu et al. 2014). Thus, this fossil cannot be confidently placed into a 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.