Phylogeny of Vascular Plants

Abstract

Morphological and molecular analyses resolve many aspects of vascular plant phylogeny, though others remain uncertain. Vascular plants are nested within bryophytes; lycopsids and zosterophylls are one branch of crown-group vascular plants, and euphyllophytes (Psilophyton, sphenopsids, ferns, seed plants) are the other. In Filicales, Osmundaceae are basal; water ferns and Polypodiaceae sensu lato are both monophyletic. Seed plants are nested within progymnosperms, and coniferophytes are nested within platyspermic seed ferns. Morphology indicates that angiosperms and Gnetales are related, but detailed scenarios depend on uncertain relationships of fossils; molecular data are inconsistent but indicate that both groups are monophyletic. Amborella, Nymphaeales, Austrobaileya, and Illiciales appear basal in angiosperms. Groups with tricolpate pollen form a clade (eudicots), with ranunculids and lower hamamelids basal. Most eudicots belong to the rosid and asterid lines, with higher hamamelids in the rosid line and dilleniids scattered in both. Alismids, Arales, and Acorus are basal in monocots; palms are linked with Commelinidae.

Cycads: evolutionary innovations and the role of plant-derived neurotoxins

“…If cycads are the sister group to the seed plants, then AXILLARY branching is a SYNAPOMORPHY for a clade composed of Ginkgo, Conifers, Gnetales and flowering plants. If Gymnosperms are monophyletic and are the sister group to the flowering plants, then axillary branching must have evolved twice, once in Gymnosperms starting with Ginkgo and once in flowering plants as has been suggested by others [11].…”

“…Cycads are a combination of PLESIOMORPHIC and APOMORPHIC traits, which are useful for studying plant evolution. Traditional paleontological studies place cycads within the earliest group of seed plants called the 'cycadophytes', which also include the Cycadeoidales and the original seed plants -the seed ferns (Pteridospermales) -leaving cycads as the only surviving group from this ancient stock [11]. Modern cycads comprise 11 genera (Fig.…”

On the Phylogeny and Biogeography of the Genus Oryza

“…These two species have some characteristics similar to Leersia and may be considered to represent species on the boundary of the genus Oryza . Early monocots may have been aquatic (Doyle 1998) and living in forested areas or forest margins (Kellogg 2001). Among Oryza species, species of the O. ridleyi complex inhabit such environments and are generally considered a 'basal' group in analyses of Oryza (Aggarwal et al 1999, Iwamoto et al 1999, Joshi et al 2000, Wang et al 1992.…”

Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

“…Proposed homologies between ovulate structures of Caytonia (left) and angiosperms (right), from Doyle (1978), following Gaussen (1946) and Stebbins (1974). (above) and proposed steps in transformation of the leaf-cupule complex into an angiosperm carpel (below), from Retallack and Dilcher (1981). bract-cupule complex (Doyle 1998a); in this article I will call it a leaf-cupule complex, because the subtending leaf was essentially unmodified. The cupule has been interpreted in many ways (Retallack andDilcher 1981, Pigg andTrivett 1994): as a sporophyll fused to a leaf, a sporophyll on an axillary shoot fused to a leaf, or an adaxial fertile segment of a leaf (analogous to the fertile segment of Ophioglossales : Kato 1990).…”