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1 December 2016 Pinaceous Wood from the Lower Cretaceous (Barremian—Early Aptian) of California, USA; Lower Chickabally Member, Budden Canyon Formation
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The Budden Canyon Formation is a Cretaceous unit spanning the Valanginian—Turonian interval in northern California. This marine unit includes plant-fossiliferous near-shore sequences, with richest plant fossil occurrences in the Hauterivian—Aptian. The Lower Chickabally Member (Barremian—early Aptian, ca. 125 Ma) hosts a rich flora preserved anatomically in carbonate concretions, near the town of Ono. The material is dominated by conifers: wood, foliage, cones and dispersed seeds. We characterize the anatomy of a coniferous trunk. The wood exhibits axial and radial resin canals with thick-walled epithelial cells, distinct growth rings, and conspicuous early to late wood transition. Axial tracheids bear radial uniseriate and opposite biseriate pitting. Rays are uniseriate with biseriate portions, with scarce ray tracheids and taxodioid cross-field pitting. Traumatic resin canals form extensive tangential bands. The axial and radial resin canals indicate pinaceous affinities for the Ono wood, but several characters make it different from most extant Pinaceae. The specimen is most similar to Picea Dietrich, from which it differs in cross-field pitting. Among fossil Mesozoic genera, the Ono wood is similar to Palaeopiceoxylon Kräusel and Protocedroxylon Gothan, and to the Pinuxylon-Laricioxyion-Piceoxylon group, but is not entirely consistent with any of these genera. Pinaceous affinity of the Ono wood is consistent with presence in the Budden Canyon Formation of several types of pinaceous foliage and ovulate cones that are, however, not assignable to any extant genus in the family. Together, these indicate the presence in the unit of stem-group Pinaceae that await reconstruction as whole plants.

Jamie K. Burnett, Emma R. Fryer, Christa R. Unger, and Alexandru M.F. Tomescu "Pinaceous Wood from the Lower Cretaceous (Barremian—Early Aptian) of California, USA; Lower Chickabally Member, Budden Canyon Formation," Ameghiniana 53(6), 685-694, (1 December 2016).
Received: 14 December 2015; Accepted: 1 August 2016; Published: 1 December 2016

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