Corypheae

Abstract: A permineralised palm trunk segment from an Oligocene deposit near Springsure in southeastern Queensland is described. The palm shows some affinities to the extant tribes Corypheae (in particular to the genera Livistona and Licuala), and Caryoteae. However, as it differs from them in a number of features and there are no unique diagnostic stem or root anatomical features which define most other extant palm genera, the fossil is assigned to the form genus Palmoxylon as the new species P. queenslandicum.

Abstract: : Nuclear DNA amounts are reported for 83 species and 53 genera of palms, covering all of the six subfamilies. 4C DNA contents range between 3.89 and 55.62 pg in diploids, showing an approximate 14.3-fold variation in genome size. Polyploids have DNA contents of up to 156.40 pg/4c which demonstrates a 40.2-fold variation. Diploids with high DNA contents occur in three subfamilies of palms (Coryphoideae, Calamoideae, Arecoideae), and seem to be further restricted to particular tribes or subtribes (Thrinacinae, Borasseae, Lepidocaryeae, Caryoteae, some subtribes of Areceae). Palms from the subfamilies Nypoideae and Phytelephantoideae have the lowest DNA amounts, followed by the Phoeniceae and the Corypheae: Livistoninae from the subfamily Coryphoideae. Although DNA amounts in some genera and subtribes are usually constant, e.g., in Phoenix, Phytelephas, the Livistoninae, Dypsidinae, diploid Butiinae), considerable variation occurs at the diploid level in some large and apparently actively evolving genera such as Chamaedorea, Pinanga, Cenoma and possibly Bactris. Formaldehyde fixation is recommended for palms, as conventional ethanol-acetic acid fixation has proved to be unsuitable for DNA estimation of Feulgen-stained nuclei by microdensitometry, since it can lead to errors up to 2.5-fold in extent. Chromosome counts are reported for 72 of the species studied, of which 42 are new.