- the solid stele of most roots, having a central core of xylem enclosed by phloem.
Origin of protostele
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for protostele
In its simplest form (as in fig. 36) it is called a protostele, and is to be found in both living and fossil plants.
In the Coal Measure period, however, the protostele was characteristic of one of the two main groups of ferns.
- a simple type of stele with a central core of xylem surrounded by a cylinder of phloem: occurs in most roots and the stems of ferns, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- The most primitive form of stele, consisting of a solid core of xylem encased by phloem or of xylem interspersed with phloem. The roots of all vascular plants, as well as the stems of lycophytes, have protosteles.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.