xylem: Quick Facts

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xylem tracheids

Illustration of a tree trunk cross-section with labeled features including outer and inner bark, sapwood, heartwood, pith, and growth rings, plus radial, tangential, and transverse surfaces.

xylem; Scots pine

stem cross section

A labeled diagram of a typical root cross section shows layers from the outside inward: root hairs, epidermis, cortex, endodermis, pericycle, and a central cylinder containing primary xylem and primary phloem.

Diagram showing a tree trunk cross-section with labeled layers: bark, cork, phloem, cambium, xylem, sapwood, and heartwood. Insets A and B illustrate an enlarged xylem vessel for upward water movement and a mature sieve element for downward sugar transport in angiosperms.

Diagram showing various fern leaf types, including simple, once-divided, falsely dichotomous, and palmate leaves, examples of leaf venation patterns, and cross-sections of petioles illustrating internal vascular arrangements.

Diagram comparing xylem and phloem cells, showing labeled illustrations of a vessel member, tracheids, and fiber for xylem on the left, and a sieve element, companion cell, sieve plate, sieve areas, and fiber for phloem on the right.

How the vascular system works in plants

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Topics

secondary xylem primary xylem lignin Cellulose vessel tracheid tylose suberin vessel cell perforation plate phloem