The first-formed elements of the primary xylem in a plant organ, maturing before elongation of the surrounding plant tissue is complete and therefore often subsequently distorted or destroyed by this process.
Origin
Late 19th century. After German Protoxylem.
Definition of protoxylem in US English:
protoxylem
noun
Botany
The first-formed elements of the primary xylem in a plant organ, maturing before elongation of the surrounding plant tissue is complete and therefore often subsequently distorted or destroyed by this process.