main stem

Everything that might hinder its development is removed, and any off-shoot of the main stem is skilfully cut off.

Nephews and cousins bearing the same name had succumbed to intermarriage and degeneracy, yet the main stem had grown straight.

The congestion on the main stem of the Pennsylvania railway between Pittsburg and Philadelphia is a case in point.

Its trunk was buried in the tangle of rank summer growth, but a branch had been broken off and left a hole in the main stem.

Flat, cartilaginous main stem, much branched, and all beset with pinnul.