tracheids's Usage Examples:

In Gymnosperms, where vessels and fibres are absent, the late summer wood is composed of radially narrow thick-walled tracheids, the wood of the succeeding spring being wide-celled and thin-walled, so that the limit of the years growth is very well marked.

All transitions are found between such forms and typical tracheids.

The secondary wood of Ephedra consists of tracheids, vessels and parenchyma; the vessels are characterized by their wide lumen and by the large simple or slightly-bordered pits on their oblique end-walls.

Each strand of spiral or annular first-formed tracheids is called a protoxylem strand, as distinct from the metaxylem or rest of the xylem, which consists of thick-walled tracheids, the pits of which are often scalariform.

metu starchy xylem-parenchyma, which, when the xylem is bulky, usually appear among the tracheids, the phloem also often being penetrated by similar bands of phloem-parenchyma.

In the stele of the root the strands of tracheids along the lines where the xylem touches the pericycle are spiral or annular, and are the xylem elements first formed when the cylinder is developing.

The vessels and tracheids are very various in size, shape and structure in different plants.

As a bundle is traced towards its blind termination in the mesophyll the peridesmic stereom first disappears, the sieve-tubes of the phloem are replaced by narrow elongated parenchyma cells, which soon die out, and the bundle ends with a strand of tracheids covered by the phloeotermic sheath.