amphivasal

amphivasal

[¦am·fə¦vā·zəl]
(botany)
Having the xylem surrounding the phloem, as seen in certain vascular bundles.
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).
Vascular tissue is in small amphivasal concentric to possible collateral bundles with breakdown of phloem to solid carbon.
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