Wood anatomy of Late Triassic trees in Petrified Forest National Park, Arizona, USA, in relation to Araucarioxylon arizonicum Knowlton, 1889

Thin sections from the three syntypes of Araucarioxylon arizonicum Knowlton, 1889 were re-examined and found to be anatomically distinct. Two of the syntypes are similar and, considering Araucarioxylon ("Araucaroxylon") Kraus, 1870 as nomen superfluum, those two are placed in Pullisilvaxylon gen. n. as nomen novum (lectotype Pullisilvaxylon arizonicum). The third specimen, known as the 'Sherman log', is transferred to Chinleoxylon knowltonii gen. et sp. n. Permineralized woods in three randomly sampled large-diameter logs assumed to be A. arizonicum plesiotypes were found to be anatomically distinct, two being species within Silicisilvaxylon gen. n., the third named Crystalloxylon imprimacrystallum gen. et sp. n. Thus, following descriptions of Arboramosa semicircumtrachea