Begonia, L.

Camfield, Rebecca & Hughes, Mark, 2018, A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India, European Journal of Taxonomy 396, pp. 1-116 : 5-10

Identification keys for Begonia of Northeast India

In order to make the account easier to use by non-specialists and to aid identification of sterile material, the species are divided into seven groups based on overall leaf similarity, and each group given a key. First choose a group by comparing leaf outlines in Figs 2–4 , and choosing one of the seven groups. Several species appear in more than one group due to variation in leaf morphology within species.

Group 1 – Leaves scalloped, lobed or incised ( Fig. 2A )

1. Leaves peltate .......................................................................................................... B. josephi A.DC.

– Leaves basifixed ................................................................................................................................ 2

2. Leaves deeply incised up to ¾ of way to petiole base ...................................................................... 3

– Leaves scalloped, lobed or shallowly incised up to ¼ of way to petiole base .................................. 6

3. Plant with main stem, leaves rarely over 20 cm long, inflorescence from leaf axils ........................ 4

– Plant stemless, leaves at least 20 cm long, inflorescence from rhizome ........................................... 5

4. Plant up to 100 cm high, generally hirsute, petiole 10–30 cm long, flowers and fruit red setose ..................................................... B. difformis (Irmsch.) W.C.Leong, C.I Peng & K.F.Chung

– Plant up to 200 cm high, generally glabrous, petiole 5–15 cm long, flowers and fruit glabrous ................................................................................................................ B. sikkimensis A.DC.

5. Petiole with sparse hairs, lobes branched with acuminate tips, male flowers with 4 tepals, female flowers with 4–6 tepals, main wing up to 3 cm long, oblong side wings 3–5 mm long that do not extend along pedicel .......................................................................... B. koelzii R.Camfield sp. nov.

– Petiole with dense hairs, lobes linear with caudate tips, male flowers with 2 tepals, female flowers with 2 tepals, main wing up to 2 cm long, curved side wings 1–2 mm long that extend along pedicel ........................................................................ B. shilendrae Rekha Morris & P.D.McMillan

6. Stem, petioles and tepals glabrous .................................................................................................... 7

– Stem, petioles, and tepals with hairs ................................................................................................. 8

7. Leaves broadly dentate (scalloped), anther connective not extended, styles 2 .. B. megaptera A.DC.

– Leaves acutely dentate, anther connective extended, styles 3 ......................... B. sikkimensis A.DC.

8. Stipules <15 mm long, flowers yellow, styles 3, fruit capsule <1 cm long ..... B. flaviflora H.Hara

– Stipules> 15 mm long, flowers white to pink, styles 2, fruit capsule> 1 cm long .......................... 9

9. Leaf upper surface hispidulous on veins only, outer tepals red setulose on reverse, fruit capsule red setulose, longest wing curved and up to 3 cm long ............................................................................ ................................................................ B. difformis (Irmsch.) W.C.Leong, C.I Peng & K.F.Chung

– Leaf upper surface hirsute/strigose or verrucose all over, outer tepals tomentose on reverse, fruit capsule glabrous or with tomentose, longest wing oblong and up to 2 cm long .. B. palmata D.Don

Group 2 – Leaves ovate, entire/undulate and asymmetric ( Fig. 2B )

1. Leaves glabrous above (or with very sparse microscopic hairs) ...................................................... 2

– Leaves hairy above ........................................................................................................................... 6

2. Plant with a main stem, up to 120 cm high, leaves not variegated, primary peduncle 2–5 mm ........ ................................................................................................................ B. roxburghii (Miq.) A.DC.

– Plant rhizomatous, up to 30 cm high, leaves variegated or not, primary peduncle 5–20 cm .......... 3

3. Leaves broadly ovate, smoothly bullate, styles 2, winged fruit ........................................................ 4

– Leaves narrowly ovate, not bullate, styles 4, wingless fruit ............................................................. 5

4. Lamina variegated with a broad ring, flowers white to pink ........................................... B. rex Putz.

– Lamina variegated with markings between main veins, flowers yellow .............. B. xanthina Hook.

5. Leaves usually variegated, outer tepals 1–3 cm long and acute, stamens in a globose cluster, fruit 2 cm long and rhomboid-elliptic ............................................................................. B. burkillii Dunn

– Leaves uniform pale green, outer tepals 2–5 cm long and rounded, stamens in loose rosette, fruit 1 cm long and obpyramidal ................................................................................. B. handelii Irmsch.

6. Leaves variegated ............................................................................................................................. 7

– Leaves not variegated ..................................................................................................................... 10

7. Plant 20–30 cm high, leaves ovate with ring/band markings .......................................................... 8

– Plant <20 cm, leaves ovate-orbicular with spot/dot markings ........................................................ 9

8. Leaf surface bullate, peduncles, flowers and fruit glabrous, anther connective acuminate, wing rounded oblong ................................................................................................................ B. rex Putz.

– Leaf surface with strigose/verrucose, peduncles, flowers and fruit with hairs, anther connective rounded, longest wing crenulated ...................................................................... B. annulata K.Koch

9. Leaves 4–10 cm long, upper leaf surface densely villose, 2–3 flowers, male outer tepals 15–20 mm long, 30–40 stamens, 3 styles ............................................................................ B. scintillans Dunn

– Leaves 10–30 cm long, upper leaf surface sparsely puberulous, 10–20 flowers, male outer tepals 10 –17 mm long, 15–25 stamens, 2 styles ........................................................... B. iridescens Dunn

10. Plants> 40 cm .................................................................................................................................11

– Plants <40 cm ................................................................................................................................ 12

11. Plant covered in long red hairs (5 mm long), peduncles 5–10 cm ....................... B. aborensis Dunn

– Plant with sparse short brownish or red pubescence on petioles and under surface of leaf, peduncles 15 –25 cm ...................................................................................... B. silletensis (A.DC.) C.B.Clarke

12. Plant with sparse puberlous hairs, styles 4, fruit wingless ..................... B. tessaricarpa C.B.Clarke

– Plant with dense tomentose or villose hairs, styles 2–3, fruit winged ........................................... 13

13. Leaves large, 15–20 cm long, apex acuminate, primary peduncle> 10 cm, fruit with equal wings, 2–6 mm long ................................................................................................. B. obversa C.B.Clarke

– Leaves small, 5–15 cm long, apex acute, primary peduncle <5 cm, fruit with unequal wings, longest wing 12 –30 mm long ........................................................................................ B. thomsonii A.DC.

Group 3 – Leaves lanceolate, dentate and very asymmetric ( Fig. 3A )

1. Leaves> 15 cm long, flowers white ................................................................................................. 2

– Leaves <15 cm long, flowers usually pink ..................................................................................... 3

2. Plant with red hirsute hairs, fruit 2-locular, covered in red hairs ..................... B. cathcartii Hook. f.

– Plant with puberulous hairs, fruit 3-locular, glabrous ......... Begonia × chungii C.I Peng & S.M.Ku

3. Leaves deltoid, male flowers with over 10 stamens .............................. B. lushaiensis C.E.C.Fisch.

– Leaves lanceolate, male flowers with less than 10 stamens ............................ B. pedunculosa Wall .

Group 4 – Leaves linear to lanceolate, entire to denticulate ( Fig. 3B )

1. Plant small, up to 20 cm high, stipules 5–7 mm long, flowers with striped outer tepals ................... ................................................................................. B. hatacoa var. meisneri (C.B.Clarke) Golding

– Plant large, up to 2 m high, stipules 5–15 mm, tepals not striped .................................................... 2

2. Plant pendent, petioles <2 cm, peduncles branching many times, peduncle> 3 cm long, 20–40 stamens connective not extended, styles 2, fruit with 1 enlarged wing ............................................ 3

– Plant erect, petioles 2–10 cm long, peduncles branching only a few times, peduncle <3 cm, around 60 or more stamens with connectives extended, styles 3–4, fruit wingless or ridged ..................... 4

3. Leaves 2–4 cm wide, male flowers with 4 tepals, pedicel on female flower 1 cm ............................ ............................................................................................................. B. griffithiana (A.DC.) Warb.

– Leaves 4–11 cm wide, male flowers with 2 tepals, pedicel on female flower 2–3 cm ...................... .............................................................................................................. B. nepalensis (A.DC.) Warb.

4. Plant monoecious, styles 3, fruit spherical, with 3 locules ................................ B. longifolia Blume

– Plant dioecious, styles 4, fruit rhomboid, with 4 locules ..................................... B. acetosella Craib

Group 5 – Leaves ovate and symmetric to sub-symmetric ( Fig. 4A )

1. Plant with an erect stem, peduncles arising from leaf axils .............................................................. 2

– Plant without an erect stem, peduncles arising from rhizome or tuber ............................................ 3

2. Leaves 2–7 cm long, tepals under 5 mm long, stamens 8–12 with a short connective, female flowers with 5–6 tepals, fruit wings oblong, straight edged .................................... B. wengeri C.E.C.Fisch.

– Leaves 5–20 cm long, tepals 5–10 mm long, stamens ± 30 with a very long connective, female flowers with 4–5 tepals, fruit wings rounded oblong ....................................... B. brevicaulis A.DC.

3. Upper surface of leaves glabrous ...................................................................................................... 4

– Upper surface of leaves with sparse to dense hairs .......................................................................... 7

4. Stipules over 1 cm long, flowers with striped outer tepals,> 30 stamens, styles 2 ............................ ...................................................................................................... B. hatacoa Buch. -Ham. ex D.Don

– Stipules under 1 cm, flowers without stripes, up to 20 stamens, styles 3 ......................................... 5

5. Leaves 3–10 cm long, tepals ca 5 mm long ....................................................... B. ovatifolia A.DC.

– Leaves (5–) 10–20 cm long, tepals 5–20 mm long .......................................................................... 6

6. Leaves puberulous below, stipules 2 mm long, tepals with pale fine hairs, stamens 20, female flowers with 4–5 tepals, longest fruit wing 2.5–3 cm ......................................... B. adscendens C.B.Clarke

– Leaves sparse pilose below, stipules 5–6 mm long, tepals with dark hairs, stamens 8–10, female flowers with 3–4 tepals, longest fruit wing 1–1.5 cm .......................................... B. labordei H.Lév.

7. Stipules> 5 mm long, fruit capsule glabrous ................................................................................... 8

– Stipules <5 mm long, fruit capsule covered in hairs ....................................................................... 9

8. Leaves up to 25 cm long, tepals with dark hairs, stamens 8–10, styles 3, longest fruit wing curved ................................................................................................................... B. labordei H.Lév.

– Leaves 3–15 cm long, tepals with pale fine hairs, stamens 15–40, styles 2, longest wing triangular ............................................................................................................... B. wattii C.B.Clarke

9. Leaves variegated, 3–16 cm long, petiole 5–12 cm, outer tepals serrate, pink, fruit with long fine white hairs, longest fruit wing triangular, 20–24 mm long ............................................ B. picta Sm.

– Leaves uniform green, 5–30 cm long, petioles 2–8 cm, outer tepals entire, white, fruit with scattered simple hairs, longest fruit wing rounded, 8–16 mm long ................................. B. brevicaulis A.DC.

Group 6 – Leaves ovate, shallowly dentate to denticulate and asymmetric ( Fig. 4B )

1. Leaf margin denticulate .................................................................................................................... 2

– Leaf margin shallowly, broadly dentate ............................................................................................ 3

2. Plant with an erect stem, with coarse red hairs, tepals 15–25 mm long, stamens 60–80, styles 3, fruit with thick red hairs, longest wing oblong ......................................................... B. cathcartii Hook. f.

– Plant stemless, with fine hairs, tepals 5–15 mm long, stamens 15–20, styles 2, fruit glabrous, longest wing triangular ................................................................................................... B. wattii C.B.Clarke

3. Leaves with short tomentose hairs above, 5–15 cm long .................................. B. annulata K.Koch

– Leaves glabrous (may have very sparse microscopic hairs) above, 10–25 cm long ....................... 4

4. Plant caulescent, styles 2 .................................................................................. B. megaptera A.DC.

– Plant acaulescent, styles 3–4 ............................................................................................................ 5

5. Leaves unvariegated, primary peduncle under 10 cm, outer tepals 2–5 cm long, female flowers with 4 tepals, styles 4, fruit wingless ........................................................................... B. handelii Irmsch.

– Leaves variegated with pale spots, primary peduncle over 10 cm, outer tepals up 2 cm long, female flowers with 5–8 tepals, styles 3, fruit winged .................................................... B. beddomei Hook.

Group 7 – Leaves lanceolate (deltoid), symmetric ( Fig. 4C )

1. Plant with an erect stem, inflorescences arising from leaf axils or terminal ...................................... ................................................................................................................ B. lushaiensis C.E.C.Fisch.

– Plant stemless, inflorescences arising from rhizome ........................................................................ 2

2. Plant hairy, tepals serrate, female flowers with 4–5 tepals, stamens 30 ........................ B. picta Sm.

– Plant glabrous to slightly hairy, female flowers with 2–3 tepals, stamens <20 .............................. 3

3. Leaves 3–13 × 2–7 cm, stamens 15–20, dioecious, tepals glabrous, fruit with 3 equal rounded wings, tepals persistent ................................................................... B. dioica Buch. -Ham. ex D.Don

– Leaves 9–20 × 6–16 cm, stamens 8–10, monoecious, tepals hairy, fruit with 1 long triangular wing and 2 short wings, tepals deciduous ..................................................................... B. labordei H.Lév.

Figures

Fig. 2. Leaf tracings. A. Group 1: scalloped, lobed or incised leaves. B. Group 2: ovate, asymmetric, and entire leaves.

Fig. 3. Leaf tracings. A. Group 3: lanceolate, dentate and very asymmetric leaves. B. Group 4: linear to lanceolate, and entire to denticulate leaves.

Fig. 4. Leaf tracings. A. Group 5: ovate and symmetric to slightly asymmetric leaves. B. Group 6: ovate, asymmetric and shallow dentate to denticulate leaves. C. Group 7: lanceolate (deltoid) and symmetric leaves.