1a

Perfect stamens less than 5, or if 5 not all equal

(2)

1b.

Perfect stamens 5, all equal

(5)

2a

Perfect stamens 2; flowers zygomorphic, nearly 2-lipped, corolla lobes deeply cleft.

1.       Schizanthus

2b

Perfect stamens more than 2, didynamous

(3)

3a

Stamens 4; fruit a berry or capsule; plants woody

2.       Brunfelsia

3b

Stamens 5; 4 in two pairs, fifth very small or rudimentary; fruit a capsule; plants herbaceous

(4)

4a.

Corolla longer than 3 cm, usually funnel-shaped; both anther lobes  developed  in all the four stamens.

3.       Petunia

4b

Corolla shorter than 3 cm, salver-shaped; shorter  pair of stamens with only one anther lobe developed.

4.       Browallia

5a

Fruit fleshy when mature, not splitting to dehisce

(6)

5b

Fruit  a dry capsule, splitting to dehisce

(18)

6a

Anthers forming a cone around the style, opening by terminal pores or lengthwise.

(7)

6b.

Anthers  not forming a cone, distinct, dehiscing longitudinally

(9)

7a

Anthers with broad filament and connective clearly separating anther lobes; dehiscence by terminal pores or lengthwise.

5.       Cyphomandra

7b

Anther lobes close together, not separated by broad connective.

(8)

8a

Calyx with distinct lobes above tube, 5-nerved; leaves entire or divided; plants unarmed or armed, herbaceous or woody

6.       Solanum

8b.

Calyx truncate with 5-10 teeth below the rim, 10-ribbed; leaves entire; plants unarmed, woody

7.       Lycianthus

9a.

Corolla tube in flower at least 4 times longer than lobes; seeds usually less than 12 in fruit; plants woody, unarmed.

8.       Cestrum

9b

Corolla tube in flower  not more than 3 times longer than lobes; seeds usually more than 12 in fruit.

(10)

10a

Plants woody; flowers tubular with narrow limb

9.       Iochroma

10b

Plants  herbaceous; flowers rotate or funnel-shaped

(11)

11a

Calyx enlarged at least as long as fruit; plants herbaceous

(12)

11b

Calyx  scarcely enlarged in fruit, much shorter than fruit

(15)

12a

Calyx almost as long as fruit, spreading; flowers in clusters

10.   Atropa

12b

Calyx longer than fruit, bladder-like

(13)

13a

Flowers several together; corolla 1 cm across

11.   Withania

13b

Flowers solitary.

(14)

14a

Flowers less than 1.5 cm across; ovary 2-celled; fruiting calyx ovoid, 5-toothed.

12.   Physalis

14b

Flowers more than 2 cm across; ovary 3-5-celled; fruiting calyx cordate, winged. 5-parted.

13.   Nicandra

15a

Plants herbaceous; corolla campanulate or rotate.

(16)

15b

Plants woody; corolla funnel-shaped or campanulate.

(17)

16a

Leaves all basal; root swollen; fruit globose

14.   Mandragora

16b

Leaves on stem and branches; root not swollen; fruit usually elongated.

15.   Capsicum

17a

Plant spiny at nodes; flowers 1-4 in each cluster; corolla funnel-shaped, lilac-purple; berry  globose, mostly red .

16.   Lycium

17b

Plant not spiny at nodes; flowers several in dense axillary clusters; corolla campanulate, white;  berry orange.

17.   Ancistus

18a

Capsule circumscissile (opening through a lid).

(19)

18b

Capsule opening lengthwise or bursting irregularly.

(21)

19a

Flowers solitary, distant.

18.   Scopolia

19b

Flowers several in a distinct inflorescence

(20)

20a

Upper  flowers forming a raceme or spike.

19.   Hyoscyamus

20b

Upper flowers forming a corymb.

20.   Physochlaina

21a

Fruiting calyx reflexed, much shorter than capsule.

(22)

21b.

Fruiting calyx not reflexed, nearly covering the fruit.

21.   Nicotiana

22a

Fruit prickly; corolla erect, less than 15 cm long, calyx circumscissile, the upper part falling off; plants herbaceous.

22.   Datura

22b

Fruit not prickly; corolla nodding, longer than 15 cm; calyx not circumscissile, upper part not falling off; plants woody

23.   Brugmansia