Table 3 Leaf morphological comparisons between Bauhinia and its allies (Fig. 2; see Additional file 4)

Length/(Width/2)

2.191

3.306

3.439

2.329

2.101

2.572

2.798

1.422

2.750

1.702

2.612

1.761

Dissection index (Perimeter/[2sqrt (π × Area)])

1.350

1.320

1.388

1.322

1.183

1.181

1.232

1.447

1.313

1.121

1.490

1.198

Apex

Obtuse, acuminate or acute

Acuminate or acute, rarely obtuse

Acute

Acute or slightly obtuse

Acuminate

Acuminate, with a drip tip

Acuminate or acute, rarely obtuse

Obtuse or rounded

Obtuse, acuminate or acute

Obtuse

Acuminate or acute

Rounded

Base

Cuneate, truncate, or Slightly to deeply cordate

Cuneate, truncate or slightly cordate, rarely deeply cordate

Slightly or shallowly cordate

Moderately to deeply cordate

Deeply cordate

Slightly cordate

Slightly to deeply cordate or cuneate, rarely truncate

Slightly to deeply cordate

Slightly to deeply cordate, raely cuneate

Cuneate

Slightly to deeply cordate

Moderately cordate

Lobation

Bilobate or bifoliolate, rarely unifoliolate

Bilobate or unifoliolate, rarely bifoliolate

Bilobate

Bilobate

Unifoliolate

Unifoliolate

Bilobate or unifoliolate

Bifoliolate

Bilobate, bifoliolate or unifoliolate

Bilobate

Bilobate, rarely bifoliolate

Unifoliolate

Texture

Chartaceous to coriaceous

Mainly coriaceous

Coriaceous

Chartaceous

Chartaceous

Coriaceous

Mainly chartaceous

Chartaceous

Chartaceous to coriaceous

Mainly coriaceous

Mainly coriaceous

Chartaceous

Sinus

No or < 120°

No or < 80°

20°–30°

30°–45°

No

No

No or < 130°

15°–30°

No or < 75°

80°–90°

No or < 25°

70°–80°

1° veins

Actinodromous or acrodromous

Actinodromous or acrodromous

Actinodromous

Actinodromous

Actinodromous

Actinodromous

Actinodromous or acrodromous

Actinodromous

Actinodromous or acrodromous

Actinodromous

Actinodromous or acrodromous

Actinodromous

5–13 in number Not branched to frequently branched

5–9 Not branched or less branched, frequently branched rarely

7–9 Less branched

9–11 Branched

7 Frequently branched

7 Branched

5–9 Not branched to frequently branched

8–10 Frequently branched

5–13 Not branched to frequently branched

11 Frequently branched

7–11 Not branched to frequently branched

9 Frequently branched

2° veins

Craspedodromous, eucamptodromous or brochidodromous

Craspedodromous, eucamptodromous, rarely brochidodromous

Craspedodromous

Eucamptodromous

Cladodromous

Eucamptodromous

Brochidodromous or eucamptodromous

Craspedodromous or eucamptodromous

Brochidodromous craspedodromous, 1 or eucamptodromous

Simple brochidodromous

Craspedodromous, eucamptodromous or brochidodromous

Cladodromous

Epidermal anatomy ([7, 17–19, 21, 22, 62–69], this paper)

Epidermal walls straight, wavy or sinuate; stomata paracytic, anomocytic, anisocytic or tetracytic; trichomes multicellular, uniseriate, unicellular or no; glands present or not

Epidermal walls straight or wavy; stomata anomocytic or paracytic, trichomes uniseriate or multiseriate, glandular; glands present or not

Epidermal walls straight or slightly curved; stomata paracytic; no trichome; no gland

Not preserved

Trichomes sometimes sparse, caducous; minute intrastipular trichomes

Subglabrous or almost glabrous, with minute trichomes on the veins

Epidermal walls straight; stomata tetracytic; no trichome

Epidermal walls wavy or sinuate; stomata tetracytic; no trichome

Epidermal walls wavy or sinuate; stomata anisocytic, tetracytic, anomocytic or paracytic; trichomes on both surfaces; no gland

Epidermal walls straight; stomata anomocytic or anisocytic; trichomes multicellular, unicellular, uniseriate and hooked; no gland

Epidermal walls undulate or sinuate; trichomes glandular, multicellular, uniseriate; no gland

Trichomes linear, canaliculate, with a ring and conical base or not; no gland