1	"Base of sinus between corolla lobes truncate or generally with a variously shaped, sometimes fringed appendage, generally > 1 mm wide"	Gentiana
1	"Base of sinus between corolla lobes unappendaged, acute, << 1 mm wide"	2
2	"Corolla +- rotate (bell-shaped), lobed +- to base, nectary pits prominent, fringed"	3
2	"Corolla not rotate, with distinct tube, nectary pits 0 (but corolla sometimes with fringes or scales, nectaries sometimes elsewhere)"	4
3	"Calyx, corolla 4-lobed; cauline leaves opposite or whorled; nectary pits generally 1 per corolla lobe (if 2, stem generally > 1 m, > 1.5 cm diam)"	Frasera
3	"Calyx, corolla (4)5-lobed; cauline leaves generally (sub)opposite or some alternate; nectary pits 2 per corolla lobe --- stem generally < 1 m, < 1 cm diam"	"Swertia {Swertia perennis}"
4	"Corolla widely bell-shaped, lobes >> tube"	"Eustoma {Eustoma exaltatum subsp. exaltatum}"
4	"Corolla narrowly or not bell-shaped, lobes <= tube"	5
5	"Calyx not appressed to, much wider than corolla tube; corolla yellow"	"Cicendia {Cicendia quadrangularis}"
5	"Calyx +- appressed to, not much wider than corolla tube; corolla pink, blue, violet, or white"	6
6	"Corolla salverform, white or generally pink"	7
6	"Corolla not salverform, generally blue to violet or white"	8
7	"Stigmas 2, elliptic to ovate"	Centaurium
7	"Stigmas 1, 2-lobed, or 2, stigmas or lobes wedge- to fan-shaped"	Zeltnera
8	"Corolla (17)20--55 mm, lobes +- entire to serrate, jagged, or fringed, without fringes or scales on adaxial surface"	Gentianopsis
8	"Corolla < 20 mm, lobes +- entire, with fringes or scales on adaxial surface near base"	9
9	"Flowers 1, terminal on branches, parts generally in 4s; pedicels generally >> subtending internode"	"Comastoma {Comastoma tenellum}"
9	"Flowers in terminal, also sometimes subterminal cymes, parts generally in 5s; pedicels generally < subtending internode"	"Gentianella {Gentianella amarella subsp. acuta}"