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Later, 'metaxylem' develops in the strands of xylem. Metaxylem vessels and cells are usually larger; the cells have thickenings typically either in the form of ladderlike transverse bars (scalariform) or continuous sheets except for holes or pits (pitted).
Spirogyra (common names include water silk, mermaid's tresses, and blanket weed) is a genus of filamentous charophyte green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is characteristic of the genus.
The presence of vessels in xylem has been considered to be one of the key innovations that led to the success of the flowering plants. It was once thought that vessel elements were an evolutionary innovation of flowering plants, but their absence from some basal angiosperms and their presence in some members of the Gnetales suggest that this hypothesis must be re-examined; vessel elements in ...
Roussea simplex is a liana of 4–6 m high. The wood vessels have very oblique oval openings which are subdivided by about 20 (maximally 50) bars (this is called scalariform), while the side walls have pits in rows and lack spiral-shaped thickenings.
The word scalar does have a sense "resembling a ladder"—though it has rarely been used with that meaning—and scalariform has a similar meaning; I can't find any evidence that they've been used to mean "resembling a staircase", however. Deor 02:12, 8 September 2008 (UTC)
Prefix meaning "position away from". [1] abaxial Surface of an organ facing away from the organ's axis, e.g. the lower surface of a lateral organ such as a leaf or petal. [2] Contrast adaxial. abort To abandon development of a structure or organ. [3] abscission Natural shedding of an organ that is mature or aged, as of a ripe fruit or an old ...
The vessel elements of Pentaphragma have features universally interpreted as primitive in dicotyledons: scalariform perforation plates with numerous bars; pit membrane remnants in perforations; scalariform lateral wall pitting; the genus also has fiber-tracheids with prominently bordered pits. The presence of occasional scalariform perforation ...
Mougeotia is able to reproduce sexually, through a process known as conjugation. It is isogamous, with two different but identically appearing gamete types. [4]In scalariform conjugation, cells of two separate filaments line up parallel to one other.