rootcap

from The Century Dictionary.

• noun A cap-like layer of parenchymatous cells which occurs at the tip of growing roots.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) A mass of parenchymatous cells which covers and protects the growing cells at the end of a root; a pileorhiza.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A mass of parenchymatous cells that covers and protects the growing cells at the end of a root.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun thimble-shaped mass of cells covering and protecting the growing tip of a root