Triloboxylon Ashlandicum Gen. And Sp. N. From the Upper Devonian of New York

Abstract

A new taxon is described from the Upper Devonian, Oneonta formation in the northern Cats‐kills of New York. Triloboxylon gen. n. is represented by petrifactions showing two orders of branching. The main axis bears branches spirally and the latter bear the ultimate appendages spirally. Ultimate appendages branch dichotomously twice, in one plane. Primary xylem of the main axis and branches is three‐armed with mesarch protoxylem extending in a continuous band within each arm. Primary xylem of the ultimate appendage is terete and dichotomizes twice. Metaxylem elements are characterized by scalariform and circular‐bordered pitting on all walls. The cortex is composed entirely of isodiametrical parenchyma cells. Triloboxylon is compared with other genera with three‐lobed protosteles. Its possible affinity with the Aneurophytales is shown. The morphological nature of the “frond” of the Aneurophytales and the possibility that the group possesses the morphological equivalent of simple leaves are discussed.

The Primary Body of Rellimia thomsonii: Integrated Perspective Based on Organically Connected Specimens

“…335.55c6-1. Scheckler and Banks 1971a;Matten 1974;Stein and Beck 1983Matten 1973Arnold 1935Matten 1973;Stein 1982 Kräusel andWeyland 1929;Serlin and Banks 1978;Schweitzer andMatten 1982 Beck 1957;Scheckler and Banks 1971aScheckler and Banks 1971bMatten and Banks 1966Scheckler and Banks 1971a;Scheckler 1975 A metaxylem character that varies among members of the Aneurophytales is presence of xylem parenchyma within the primary xylem of Reimannia, Tetraxylopteris, Proteokalon, and T. ashlandicum (table 1). With the exception of Reimannia, which lacks secondary xylem, these are the same aneurophytalean genera that have ray tracheids in addition to ray parenchyma in the secondary xylem (Dannenhoffer and Bonamo 2003).…”

“…This arrangement of protoxylem may prove useful in distinguishing a group of genera allied with Aneurophyton. For genera with more than four protoxylem strands, previous workers used protoxylem configuration, including number of protoxylem strands within a cross section or interconnection between strands, to make generic distinctions (Matten and Banks 1966;Scheckler andBanks 1971a, 1971b;Scheckler 1975;Bonamo 1977;Serlin and Banks 1978). Stein (1982) argued against using this character to separate genera because there is not enough known about the internal structure of the taxa to conclusively distinguish them from one another.…”

“…The initial report of Triloboxylon ashlandicum (Matten and Banks 1966), based on anatomical fragments, describes a three-lobed mesarch protostele lacking parenchyma and containing continuous bands of protoxylem in cross section, not discrete strands. Traces to higher orders of axes are first rounded, then become three ribbed; those to ultimate appendages are terete and dichotomizing.…”

“…Tetraxylopteris is currently best known from compressions in New York (Beck 1957;Bonamo and Banks 1967;Scheckler and Banks 1971a) and Venezuela (Hammond and Berry 2005) showing variations in branching, phyllotaxis, and locations of vegetative appendages or fertile organs. Anatomy of the New York species, Tetraxylopteris schmidtii, is also known, with permineralizations occasionally associated with the compressions (Beck 1957;Matten and Banks 1967;Scheckler and Banks 1971a).…”

“…Aneurophyton germanicum from New York and Germany has been described from compressions, but some anatomy has also been referred to the species (Krä usel and Weyland 1923). In addition, several aneurophytalean taxa from New York, including Reimannia aldenense (Arnold 1935), Triloboxylon arnoldii (Matten 1974), Triloboxylon ashlandicum (Matten and Banks 1966), Proteokalon petryi (Scheckler and Banks 1971b), and Cairoa lamanekii (Matten 1973), are recognized based on features of internal anatomy.…”