amphivasal

amphivasal

[¦am·fə¦vā·zəl]
(botany)
Having the xylem surrounding the phloem, as seen in certain vascular bundles.
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References in periodicals archive ?
Formation of the amphivasal vascular bundles indicates the presence of the monocot cambium and the commencement of the secondary growth (Diggle & DeMason, 1983b).
Secondary vascular bundles usually differ from primary bundles in having the amphivasal arrangement of xylem and phloem (xylem surrounding the phloem), whereas the latter usually have a collateral arrangement (Tomlinson & Zimmemann, 1969; Jura-Morawiec & Wiland-Szymanska, 2014).
These bundles are amphivasal rather than collateral.
11c) are clearly amphivasal, with tracheids surrounding a central strand of phloem.
completely joined to form an outer horseshoe-shaped amphivasal bundle
vascular band is amphivasal, a condition in which the phloem is