1) have relatively small amounts of ray and axial parenchyma tissue compared with Gnetales
It points towards existence of Gnetales
. Marsupipollenites triradiatus is wide spread in the upper Permian sediments in almost all Gondwanaland countries.
Vessel dimensions in liana and tree species of Gnetum (Gnetales
Former diversity of Ephedra (Gnetales
): evidence from Early Cretaceous seeds from Portugal and North America.
Phylogeny of seed plants based on all three plant genomic compartments: extant gymnosperms are monophyletic and Gnetales
are derived conifers.
Within the context of the structurally diverse female gametophytes of seed plants, it has long been recognized (Coulter 1914) that some of the most anomalous seed plant female gametophytes are found in species of Gnetum, which with Welwitschia and Ephedra comprise the Gnetales
. Although descriptions of female gametophyte structure and development in Gnetum are highly variable and often contradictory (Gifford and Foster 1989), recent work has established that at sexual maturity the female gametophyte of G.
(Ephedra, Gentum, Welwitschia) is a distinct lineage among the six major groups of extant gymnosperms which has occupied various and contested positions in hypothesized seed plant phytogenies (Graham & lies, 2009; Mathews, 2009; Rydin and Korall, 2009).
Second, all the extant gymno-ovulate seed plants (Brown's "cycads, conifers and Gnetales
"--to which must be added Ginkgo), from their fossil record, appear antecedent to the flowering plants (Knoll, 1986).
The torus-margo system works in conifers (including Gnetales
) because the pits are circular.
seed plants of Gnetales
, Cycadales, and Pinales; (2) floral scent
Oct 1907 (Gnetales
).--Type: Gnetum L.; Gnetaceae Blume, 1833.
consistently been placed near the angiosperms plus the Gnetales
Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales
A particularly relevant article by Endress (1996) analyzed many aspects of development, including "inflorescences" of the reproductive structures of Gnetales
. Gnetalean taxa, though usually having unisexual reproductive axes, occasionally have bisexual reproductive structures.
thaliana floral meristem identity gene, is another highly conserved regulatory gene with homologs in the basal angiosperms and Gnetales
(Weigel et al., 1992; Frohlich & Meyerowitz, 1997).