The great yellow gentian (Gentiana lutea), which has a very bitter taste.

plural of bitterweed

Any plant in the genus Ambrosia, especially Ambrosia artemisiifolia (common ragweed). / The plant Helenium amarum (yellow sneezeweed). / Parthenium hysterophorus (false ragweed)

plural of bittermelon

Alternative form of bitter melon

A bittern of the genus Ixobrychus. / A bittern of the species Ixobrychus minutus.

A species of fish, Rhodeus amarus, originating in Europe, ranging from the Rhone River basin in France to the Neva River in Russia.

In a bittersweet manner.

plural of European bitterling

plural of little bittern