منابع مشابه
How early ferns became trees.
A new anatomically preserved fern, discovered from the basalmost Carboniferous of Australia, shows a unique combination of very primitive anatomical characters (solid centrarch cauline protostele) with the elaboration of an original model of the arborescent habit. This plant possessed a false trunk composed of a repetitive branching system of very small stems, which established it as the oldest...
متن کاملAccelerated rate of molecular evolution for vittarioid ferns is strong and not driven by selection.
Molecular evolutionary rate heterogeneity-the violation of a molecular clock-is a prominent feature of many phylogenetic data sets. It has particular importance to systematists not only because of its biological implications, but also for its practical effects on our ability to infer and date evolutionary events. Here we show, using both maximum likelihood and Bayesian approaches, that a remark...
متن کاملMaidenhair Ferns, Adiantum, are Indeed Monophyletic and Sister to Shoestring Ferns, Vittarioids (Pteridaceae)
Across the tree of life, molecular phylogenetic studies often reveal surprising relationships between taxa with radically different morphologies that have long obscured their close affiliations. A spectacular botanical example is Rafflesia, a holoparasite that produces the largest flowers in the world, but that evolved from tiny-flowered ancestors within the Euphorbiaceae. Outside of parasitic ...
متن کاملFERNS AND FERN ALLIES OF IRAN
The pteridophyte account of Flora Iranica (ed. K.H. Rechinger) is still not published. The Caspian forests provide suitable habitats for the growth of many ferns and fern allies in Iran. In semi-arid and mountainous areas of Iran, mesophilous plants are restricted to rock crevices, waterfall proximity, stream banks and lake shores. Based on field collections and study of herbarium specimens in ...
متن کاملTypes of Foliar Dichotomy in Living Ferns
LEAVES OF CERTAIN ferns are commonly cited as "primitive" on the general theory that they have retained dichotomy of the major vascular axes of the leaf from ancient psilophyte ancestors (Zimmermann, in Verdoorn, 1938; Lam, 1948). The present study suggests a re-interpretation to be based on comparisons with ordinary fern leaves, "pinnate" in the arrangement of their main veins. The term "folia...
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ژورنال
عنوان ژورنال: Botanical Gazette
سال: 1879
ISSN: 0006-8071
DOI: 10.1086/325206