Key for Gentianaceae

1Saprophytic plants without chlorophyll (mycoheterotrophic); leaves scale-like, yellow, white, pink, or purple
1'Plants with chlorophyll; leaves not scale-like, green
2Calyx lobes connate into a tubular calyx; corolla far exceeding calyx, long-persistent; plants variously coloured
2'Calyx with almost free lobes; corolla barely exceeding calyx, soon falling off; plants completely white
3Flowers/fruits axillary
3'Flowers/fruits terminal
4Plants woody, shrubs or small trees, sometimes perennial herbs; leaves large, 6.5-35 cm long, 3-11-veined
4'Plants herbaceous, herbs, sometimes slightly woody at base; leaves small, 0.5-8 cm long; 1-3-veined
5Leaves lanceolate, > 1.5 cm long; flowers in clusters of 2-8 in each of the upper leaf axils, no terminal flower; perennial herb
5'Leaves linear, < 1 cm long; flowers 1-2 in upper leaf axils, with terminal flower; annual herb
6Fruit a berry; corolla lobes 8-12
6'Fruit a capsule; corolla lobes 4-5 (rarely 6)
7Calyx lobes free, decussate; corolla 6-merous
7'Calyx lobes fused at base into a campanulate or tubular calyx, imbricate; corolla 4-5-merous
8Calyx coriaceous, with a thickened, glandular dorsal area on each lobe, calyx lobes obtuse (except Symbolanthus with acute lobes, but lobes then at least 30 mm long)
8'Calyx herbaceous to membranaceous, often with thin, dorsal keels but not with a thick glandular area on each lobe; calyx lobes acute to acuminate
9Perennial plants; shrubs or small trees, all stems woody
9'Annuals or short-lived plants; herbs, sometimes woody at base
10Corolla red to pink or blue to purple; calyx divided more than 2/5 of its length
10'Corolla yellow to light green; calyx divided at most 1/3 of its length
11Corolla blue to purple; calyx divided 2/5-3/5 of its length, calyx lobes circular; capsule woody
11'Corolla red to pink; calyx divided 9/10 of its length, calyx lobes lanceolate to elliptic; capsule leathery, often glossy, nearly berry-like
12Leaves petiolate, veins visible below; bracts leaf-like; inflorescence with more than 6 flowers; pollen in monads
12'Leaves subsessile, veins not visible below; bracts scale-like; inflorescence with up to 6 flowers; pollen in tetrads
13Corolla tubes less than 2 times as long as corolla lobes (except I. tatei, with pink corollas); pollen in spinose polyads
13'Corolla tubes more than 2 times as long as corolla lobes; pollen in tetrads (polyads in C. purpurascens)
14Flowers nodding
14'Flowers erect to horizontal
15Leaves sessile; corolla 33-50 mm long, red to pink; capsule 11-13 mm long
15'Leaves petiolate; corolla 3-6 mm long, white or green; capsule 2-5 mm long
16Inflorescence a raceme or congested spike with 2-4 flowers in each whorl; flowers sessile or shortly pedicellate; stamens exerted from corolla mouth
16'Inflorescence a lax to congested cyme; flowers pedicellate; stamens included in corolla
17Inflorescence with at least some monochasially branching branches
17'Inflorescence strictly dichasially branching
18Leaf blades up to 0.3 cm wide; stigma capitate; pollen in monads
18'Leaf blades over 0.3 cm wide; stigma bilamellate; pollen in tetrads