undergrowth

noun

1. low-lying vegetation or small trees growing beneath larger trees; underbrush.
2. the condition of being undergrown or undersized.
3. short, fine hair underlying longer, outer wool or fur.

noun

1. small trees, bushes, ferns, etc, growing beneath taller trees in a wood or forest
2. the condition of being undergrown
3. a growth of short fine hairs beneath longer ones; underfur

n.c.1600, from under + growth.