Palmoxylon hebbertii, from the Lower Oligocene Goldens Ranch Formation of central Utah, U.S.A., with an analysis of some characteristics previously used in the classification of Palmoxylon

Abstract

The new species, Palmoxylon hebbertii, described here was collected from the Lower Oligocene Goldens Ranch Formation southwest of Nephi, Utah, U.S.A. In cross section, the collateral vascular bundles are generally reniform in shape with a well-developed fibrous bundle sheath and a median sinus that is very shallow or absent. They are bivascular and, in the subdermal zone, surrounded by radiating parenchyma. The phloem is well differentiated into protophloem and metaphloem elements with oblique sieve plates. The metaxylem and protoxylem vessel elements show a gradual change in the morphology of their end plates as well as in their wall thickenings. An analysis of 41 well preserved Palmoxylon species from India suggests that Stenzel's grouping of the species based on the nature of the bundle sheath is artificial and that several characteristics including the nature of the vascular tissues, used in classification of extant species, should be used.Key words: palm, Goldens Ranch Formation, Utah, Oligocene, Stenzel's grouping, Jaccard's method.

A review of the plants of the Princeton chert (Eocene, British Columbia, Canada)

“…The palm fossil record, particularly of the coryphoid palms, is well known and has been reviewed by several authors (Daghlian 1981;Nambudiri andTidwell 1998: DeVore andPigg 2009). A discussion of the biogeography of extant New World coryphoid palms can be found in Bjorholm et al (2006) and a computer-aided key of stem anatomy of coryphoid palms from Thomas and De Franceschi (2013).…”

Fossil Palms (Arecaceae, Coryphoideae) Associated with Juvenile Herbivorous Dinosaurs in the Upper Cretaceous Aguja Formation, Big Bend National Park, Texas

“…Kaul (1960), who reviewed earlier work on palm anatomy, remarked that there were no workable natural or artificial classifications for fossil palm stem anatomy. Nambudiri and Tidwell (1998) reviewed the characteristics used in classifying Palmoxylon species. They found that some of the features previously used to distinguish Palmoxylon species were features of dubious taxonomic value because they were affected by position within the stem.…”

Palaeoxylotomical studies in the Cenozoic petrified forests of Greece. Part one – palms

“…In comparing our xylotomical structures with some fossil forms already published, we took into account all the available descriptions of so-called "sabaloid palms", in fact members of the Coryphoideaea subfamily, after the last phylogenetic classification of Arecaceae of Dransfield et al (2005), usually having sclerenchyma caps of Reniformia type (sensu Stenzel 1904), as described by Schenk (1883), Berry (1924) Chiarrugi (1933), Rao & Menon (1964a), Menon (1965), Trivedi & Verma (1971a, Prakash (1962), Grambast (1957, Greguss (1954Greguss ( , 1959Greguss ( , 1969, Privé-Gill & Pelletier (1981), Gottwald (1992), Nambudiri & Tidwell (1998), Kahlert et al (2005) and Iamandei & Iamandei (2006), in which a possible extant corresponding taxon is only sometimes given.…”

“…We analyzed many published species of Palmoxylon Schenk and decided to compare only the species with fibrous sheaths of reniform type, attributed more or less explicitly to the sabaloid palms, keeping in mind that they in fact now represent the Coryphoideaea subfamily after the last phylogenetic classification of Arecaceae (see Dransfield et al 2005). The species described by Schenk (1883), Berry (1924) Chiarrugi (1933, Rao & Menon (1964), Menon (1965), Trivedi & Verma (1971a, b), Prakash (1962, Grambast (1957Grambast ( , 1964, Greguss (1954Greguss ( , 1959Greguss ( , 1969, Prive-Gill & Pelletier (1981), Gottwald (1992), Nambudiri & Tidwell (1998), Kahlert et al (2005), Iamandei & Iamandei (2006) and Iamandei et al (2018) were compared with the synthetic description of our specimens, and from the above discussion it is clear that most of them are too different from the specimens we studied, or else they are clearly identified with other forms.…”