Tmesipteris

Abstract: Chloroplast 16S rDNA sequences from the charophyte algae Spirogyra and Coleo- chaete; the bryophytes Marchantia and Sphagnum; the fern allies Equisetum, Isoetes, Selaginella, Lycopodium, Tmesipteris and Psilotum; the eusporangiate ferns Angiopteris, Botrychium, and Ophioglossum; the leptosporangiate ferns Lydogium and Doodia; the gymnosperms Ephedra and Juniperus; and six angiosperms (two monocots and four dicots) were analyzed with the parsimony algorithm PAUP to infer phylogenetic relationships. The charophytes were the designated out- group and the bryophytes were at the base of the land plant clade. Relationships of most of the fern allies and Angiopteris were unresolved but a clade containing Psilotum + Tmesipteris (Psi- lotales) was sister to a clade composed of Botrychium and Ophioglossum (Ophioglossales). A leptosporangiate fern clade was strongly supported, and this clade grouped weakly with Angiop- teris. The Selaginella 16S rDNA sequence is apparently changing at a faster rate than the other sequences as evidenced by the extremely long branch associated with Selaginella. The effect of this long branch on the overall tree topology was tested by removing Selaginella from a subsequent analysis. Trees produced without Selaginella weakly supported the placement of Lycopodium at the base of the vascular plants clade but Isoetes grouped weakly with the seed plants. Removal of Selaginella also resulted in higher bootstrap values and decay indices for the majority of the clades. The determination of phylogenetic relationships of the "fern allies," the Psi- lophyta, Lycophyta, and Sphenophyta, has proven to be elusive. Taxonomi- cally, the fern allies are generally considered to be positioned between the bryophytes and ferns but formal analyses of morphological and molecular data sets only partially resolve their relationships. In a cladistic analysis of mor- phological characters, Bremer et al. (1987) placed Psilotum at the base of vas- cular plants, the lycopsids branched off next, then Equisetum, and then the ferns. However, the portion of the clade containing the fern allies was con- structed with only four morphological characters and it is not reasonable to expect that a robust phylogeny containing highly divergent taxa can be pro- duced from such a small data set. Conversely, fossil evidence (Knoll and Roth- well, 1981; Stewart, 1983; Gensel and Andrews, 1984), characters relating to male gametogenesis (Garbary et. al., 1993), and chloroplast genome structures (Raubeson and Jansen, 1992) support the hypothesis that the lycophytes are at the base of the vascular land plant clade. Mishler et al. (1994) analyzed green plant molecular and morphological data sets separately and together, using parsimony algorithms. Some vascular land plants were included, with the fern allies represented by Equisetum, Lycopo- dium, Lycopodiella, and Selaginella. The analysis of "general" morphological characters placed the lycophytes sister to a clade containing Equisetum, ferns,

Abstract: We report the chloroplast genomes of a tree fern (Dicksonia squarrosa) and a “fern ally” (Tmesipteris elongata), and show that the phylogeny of early land plants is basically as expected, and the estimates of divergence time are largely unaffected after removing the fastest evolving sites. The tree fern shows the major reduction in the rate of evolution, and there has been a major slowdown in the rate of mutation in both families of tree ferns. We suggest that this is related to a generation time effect; if there is a long time period between generations, then this is probably incompatible with a high mutation rate because otherwise nearly every propagule would probably have several lethal mutations. This effect will be especially strong in organisms that have large numbers of cell divisions between generations. This shows the necessity of going beyond phylogeny and integrating its study with other properties of organisms.

Abstract: On the basis of ontogeny and arrangement of the surrounding cells the stomata in ferns are classified into twenty-four types of which seven – plupolocytic, pseudocopolocytic, sepcopolocytic, pseudohemiparacytic, pluhemiparacytic, pluparacytic and codiacytic – are new. The ontogenetic interrelationships among different stomatal types are traced and the role of stomata in determining the taxonomic position of Psilotum, Tmesipteris and the Ophioglossum group of genera are discussed. It is concluded that the mesogenous and mesoperigenous types of stomata are not distinct entities – one is the derived form of the other. The polocytic stoma which is mesoperigenous in origin is, however, not accepted as the direct descendant of the anomocytic (perigenous) type.

Abstract: The flavonoids of the primitive leptosporangiate ferns Stromatopteris moniliformis, Schizaea bifida, Gleichenia cunninghamii, Cardiomanes reniforme, and Hymenophyllum demissum have been identified as 3-0-glycosides of the flavonols kaempferol and quercetin. None of the examined ferns produced flavonoids which are also common to the Psilotoceae. The Psilotaceae have previously been shown to produce 0-glycosides of amentoflavone (biflavone) and apigenin (flavone) and traces of C-glycosylflavones (Wallace and Markham, 1978). These data imply that the primitive leptosporangiate ferns are not closely related to the Psilotaceae. The antiquity of rhamnose as a glycosyl moiety is suggested by its occurrence in both the primitive leptosporangiate ferns and in the Psilotaceae. SEVERAL interpretations of fern phylogeny have been published (Pichi-Sermolli, 1973). All have considered the Schizacaceae, Gleicheneaceae, Stromatopteridaceae, and Hymenophyllaceae as representing primitive leptosporangiate ferns. Most previous authors considered the Psilotaceae to represent a distinct and only remotely related taxon. However, Bierhorst (1968, 1977) challenged the position of the Psilotaceae as being a well defined entity at the divisional level. He reclassified the Psilotaceae, containing both Psilotum and Tmesipteris, into the Pteridophyta where it was closely allied with the monotypic Stromatopteridaceae. He supported this by detailed morphological studies involving ontogeny of both sporophytes and gametophytes. Most convincing were the anatomical comparisons of young sporophytes of Psilotum, Tmesipteris and Stromatopteris as well as his observation of an "annulus" on the psilotaceous synangium. However, as evidenced at a recent symposium, many morphologists are not in agreement (White, 1977; Gensel, 1977; Kaplan, 1977; Wagner, 1977). Subsequently Cooper-Driver (1977) presented phytochemical evidence that the Psilotaceae should not be allied with Stromatopteris or any other primitive (or advanced) fern. She contended that I Received for publication 28 March 1978; revision accepted 5 July 1978. The authors are grateful to Dr. Phillip Morat, Noumea, New Caledonia, and to Dr. Patrick Brownsey, The National Museum, Wellington, New Zealand for supplying Stromatopteris moniliformis. J.W.W. acknowledges the support of a New Zealand National Research Advisory Council Senior Research Fellowship and a Faculty Research Grant from Western Carolina University. the presence of amentoflavone as the only flavonoid in both Psilotum and Tmesipteris with the corresponding absence of flavonols was justification to keep the Psilotaceae as a separate entity at the divisional level. Recently Wallace and Markham (1978) documented the total flavonoid profile of species of Psilotum and Tmesipteris. They identified amentoflavone and its 0-glycosides as the major components of both genera and reported the presence of flavone-O-glycosides as minor constituents with C-glycosylflavones occurring as trace components. Although amentoflavone and its 0-glycosides have not been documented in ferns, it is known that some ferns have the ability to synthesize flavone 0-glycosides (Swain and Cooper-Driver, 1973) and C-glycosylflavones (Ueno et al., 1963; Soeder and Babb, 1972). Interestingly, a full analysis of the flavonoid glycosides of Stromatopteris and other primitive leptosporangiate ferns has not as yet been published. The present paper is a detailed account of the flavonoids of Stromatopteris moniliformis, Schizaea bifida, Gleichenia cunninghamii, Cardiomanes reniforme, and Hymenophyllum demissum. Phylogenetic implications of these compounds pertaining to the relationship of the primitive leptosporangiate ferns to themselves and to the Psilotaceae will be discussed. MATERIALS AND METHODS-Plant materialsStromatopteris moniliformis Mett. (14.0 g d.w.) was collected in March 1977, at Noumea, New Caledonia; Schizaea bifida Willd. (1.8 g d.w.) was collected on 12 April 1977, Auckland, New