Developmental features of the discontinuous stem vascular system in the rattan palm Calamus (Arecaceae-Calamoideae-Calamineae).

Calamus is a climbing palm marked by considerable internodal extension and limited stem-thickening growth, but with a surprisingly discontinuous axial vascular system. Stem bundles end blindly in a basipetal direction and are connected to each other only by narrow and late-developing transverse commissures. Vascular connection via leaf traces between stem and leaf is made over about nine plastochrons (P), but the dominant central system is completed by about P(7), with subsequent bundles forming the crowded fibrous peripheral system, which has reduced or no vascular tissues.

Diversity, distribution, and ancient taxonomic relationships within the TIR and non-TIR NBS-LRR resistance gene subfamilies.

Phylogenetic relationships among the NBS-LRR (nucleotide binding site-leucine-rich repeat) resistance gene homologues (RGHs) from 30 genera and nine families were evaluated relative to phylogenies for these taxa. More than 800 NBS-LRR RGHs were analyzed, primarily from Fabaceae, Brassicaceae, Poaceae, and Solanaceae species, but also from representatives of other angiosperm and gymnosperm families. Parsimony, maximum likelihood, and distance methods were used to classify these RGHs relative to previously observed gene subfamilies as well as within more closely related sequence clades.