Nodule of oxide of manganese from Red Clay of abyssal ocean bottom.

Oxide of Manganese

Nodule of oxide of manganese from Red Clay of abyssal ocean bottom.

Nodules on the root system of a bean plant where nitrogen-fixing bacteria live.

Nodules, root

Nodules on the root system of a bean plant where nitrogen-fixing bacteria live.

Nodules on the root system of a hairy vetch.

Nodules, root

Nodules on the root system of a hairy vetch.