Category: Hitchhiker Guide: About the most massively useful thing a hitchhiker can have.?

Questions

Common name for a small thorny tree (rue), & for its fruit?

Common name for a species of bear, similar in size to a large cat, with thick, reddish-brown fur?

Common name for about 19 species of annual herbs, of the grass family (grasses)?

Common name for about 200 species of algae belonging to the phylum charophyta of the plant kingdom?

Common name for about 2200 species of fishes, of which some 1200 are south american?