Arbuscular mycorrhiza formation in cordate gametophytes of two ferns, Angiopteris lygodifolia and Osmunda japonica.
R/M A TE B TE Marattiaceae Angiopteris evecta M/ATR A TE (G.
Progressing distally from the root, Psilophyton crenulatum, the most basal clade, comprises the psilotophytes Psilotum + Tmesipteris, followed by the equisetophyte Equisetum, the seed plant Pinus, the ophioglossalean ferns Ophioglossum + Botrychium, the marattiaceous ferns Marattia + Angiopteris, and the "leptosporangiate" clade that consists of the Filicales + the Hydropteridales [ILLUSTRATION FOR FIGURE 4 OMITTED].
Results of the complete analysis, in which marattialean ferns form a monophyletic group with the Paleozoic genus Psaronius sister to the extant genera Marattia + Angiopteris, also conform to expectations based on traditional interpretations (Gifford & Foster, 1989; Stewart & Rothwell, 1993; Taylor & Taylor, 1993).
Surface-viewed shoot apex of Angiopteris
Roots of the ferns available to us other than Angiopteris
were too slender to be readily sectioned by hand.
As part of an effort to provide data for addressing this issue, we sequenced the complete plastid genome of Angiopteris evecta (Marattiaceae).
Because Angiopteris represents a major lineage, details of its plastid genome can provide baseline data for this and other studies.
This region has the same gene order in Psilotum and Angiopteris so it is likely to be an ancestral monilophyte organization.
In Angiopteris it is located in the IR at positions 104265-104639 and 139346-138972.
The Angiopteris plastid genome contains several regions with repeat structure.
Why have the plastid genome structures of Angiopteris and Psilotum remained so constant over such a long period of evolutionary time?
If the plastid genome structure of Angiopteris has indeed remained constant since the origin of monilophytes, this would correlate with other evolutionary trends in the Marattiaceae.