Key_start

1	Inflorescences crowded 4-sided spikes; flowers opposite and decussate, subtended by specialized, membranous or submembranous, sessile, hoodlike bracts
+	Inflorescences 1-sided or rarely partly spiral, often poorly defined; flowers subtended by leaves or leaflike bracts.		(2)
2 (1)	Upper lip of calyx convex, lacking a scutellum; nutlets gray-black, with hairs longer than 0.5 mm		98 Scutellaria kingiana
+	Upper lip of calyx with a sail-like scutellum; nutlets of various colors, glabrous or with hairs shorter than 0.5 mm.		(3)
3 (2)	Apical flowers often ± spiral; nutlets with acuminate papillae terminating in a ring of hooks; inflorescences terminal, often ± scapose; bracts minute, herbaceous		1 Scutellaria discolor
+	Flowers erect, opposite; nutlets variously ornamented, mostly lacking hooked papillae; inflorescences robust and/or lateral, never scapose; bracts leaflike.		(4)
4 (3)	Flowers in terminal racemes or spikes ± sharply differentiated from the vegetative part of the stem, mostly subtended by reduced bractlike leaves.		(5)
+	Flowers in axillary racemes or, if terminal, most flowers subtended by normal leaves and with a gradual transition from these to bracts.		(6)
5 (4)	Stem leaves conspicuously petiolate, almost 2 × as long as wide, mostly obscurely dentate or rarely entire; bracts entire, short petiolate, unlike stem leaves; plants subshrubs or erect or rarely ascending herbs lacking enlarged rhizomes		Key 1 (see List of Keys below)
+	Stem leaves subsessile or short petiolate, more than 2 × as long as wide, dentate-serrate, crenate, to entire; bracts ± similar to stem leaves, gradually reduced toward stem apex; plants erect or ascending-erect perennial herbs with an enlarged and often woody rootstock/rhizome		Key 4 (see List of Keys below)
6 (4)	Flowers mainly in axillary racemes or on lateral branches; plants much branched herbs		Key 5 (see List of Keys below)
+	Flowers axillary, secund, mostly on main axis; plants perennial, mostly erect herbs.		(7)
7 (6)	Nutlets inconspicuously differentiated into adaxial and abaxial sides, tuberculate		Key 6 (see List of Keys below)
+	Nutlets conspicuously differentiated into adaxial and abaxial sides, abaxially tuberculate, adaxially spiny or smooth, with or without a membranous wing on equatorial plane.		(8)
8 (7)	Nutlets tuberculate abaxially, adaxially smooth and conical, with an apical umbo; rhizomes with long leafless stolons at nodes; stems densely spreading pilose		96 Scutellaria tuberifera
+	Nutlets densely tuberculate abaxially, adaxially densely spiny around a cylindric central umbo; rhizomes without stolons; stems glabrous to sparsely pilose apically		97 Scutellaria guilielmii