Narrowleaf Skullcap, Narrow-leaved Skullcap: Scutellaria angustifolia ssp angustifolia (Synonyms: Scutellaria angustifolia var. angustifolia, Scutellaria veronicifolia) - Corolla blue, measuring from 24-32 mm long, the throat open. Leaves fairly broad at the base, tapering quickly to fairly long petioles from 5-15 mm long.
Narrowleaf Skullcap, Small-flowered Skullcap: Scutellaria angustifolia ssp. micrantha -
Snapdragon Skullcap: Scutellaria antirrhinoides - Corolla blue, from 15-22 mm long, the throat nearly closed by the palate. Leaves fairly broad at the base, tapering quickly to long petioles from 5-15 mm long.
Marsh Skullcap, Hooded Skullcap, Willow-weed Skullcap: Scutellaria galericulata - Corolla blue, marked with white, measuring 12-15 mm long. Leaves broader at the base, narrowing abruptly to short petioles.
Blue Skullcap, Mad-dog Skullcap, Madweed: Scutellaria lateriflora -
Dwarf Skullcap: Scutellaria nana (Synonym: Scutellaria nana var. nana) - Corolla cream or pale yellowish and marked with purple, measuring 14-21 mm long. Leaves taper gradually to short petioles.