metaxylem

The protoxylem is thus found in the central core and the metaxylem in a cylinder around it.

The patterns in which protoxylem and metaxylem are arranged is important in the study of plant morphology.

Later, 'metaxylem' develops in the strands of xylem.

Functionally, metaxylem completes its development after elongation ceases when the cells no longer need to grow in size.

It includes protoxylem and metaxylem.

The stems had a central vascular column in which the protoxylem was exarch, and the metaxylem developed centripetally.

The metaxylem is thus closest to the center of the stem or root and the protoxylem closest to the periphery.

In living plants, pitted tracheids do not appear in development until the maturation of the metaxylem (following the protoxylem).

As it develops in young plants, its nature changes from protoxylem to metaxylem (i.e. from first xylem to after xylem).

The xylem development was 'mesarch', i.e. the first maturing protoxylem had later maturing metaxylem on either side.

The metaxylem is thus on both the peripheral and central sides of the strand with the protoxylem between the metaxylem (possibly surrounded by it).

A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhynia.

Actinosteles are typically exarch (protoxylem external to the metaxylem) and consist of several to many patches of protoxylem at the tips of the lobes of the metaxylem.