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24 de sept. de 2010 · Ferns come in a variety of shapes and sizes and this interactive explores the diversity of form in New Zealand ferns. The fern body consists of 3 major parts – the rhizome, the fronds and the sporangia.
Fern Structure. Ferns can have some very unusual forms and structures. The following describes fern structure and forms that people typically encounter. Leaves. The leaves of ferns are often called fronds. Fronds are usually composed of a leafy blade and petiole (leaf stalk). Leaf shape, size, texture and degree of complexity vary considerably ...
In plants, a rachis is the main axis of a compound structure. It can be the main stem of a compound leaf, such as in Acacia or ferns, or the main, flower-bearing portion of an inflorescence above a supporting peduncle. Where it subdivides into further branches, these are known as rachillae (singular rachilla).
4 de sept. de 2013 · In some ferns the aerophores extend distally into the rachis, or proximally onto the rhizomes (e.g., Mickelia and Polybotrya, both Dryopteridaceae). In those few fern species that invest their fiddleheads in a thick covering of mucilage, the lines are modified at the pinna bases into elongate peg-like structures that protrude through the ...
The fern frond (D) is emerging from an underground, horizontal stem called a rhizome (C). The frond is twice pinnately compound. The leaflets (B, also called pinnae) branch off of a central stem called a rachis (A).
7 de jun. de 2014 · This first phylogeny of Pteris on a global scale and including more than half of the diversity of the genus should contribute to a new, more reliable infrageneric classification of Pteris, based not only on a few morphological characters but also on ecological traits and geographical distribution.
12 de jul. de 2011 · The ferns comprise one of the most ancient tracheophytic plant lineages, and occupy habitats ranging from tundra to deserts and the equatorial tropics. Like their nearest relatives the conifers, modern ferns possess tracheid-based xylem but the structure–function relationships of fern xylem are poorly understood. •.
