Begonia species

Ardi, W. H. & Thomas, D. C., 2022, SYNOPSIS OF BEGONIA (BEGONIACEAE) FROM THE NORTHERN ARM OF SULAWESI AND SANGIHE ISLAND, INDONESIA, INCLUDING THREE NEW SPECIES, Edinburgh Journal of Botany 79 (405), pp. 1-50 : 4-6

Key to the Begonia species of the northern arm of Sulawesi and the Sangihe Talaud Islands

1a. Plants rhizomatous, creeping or decumbent ________________________________________ 2

1b. Plants erect _______________________________________________________________________ 6

2a. Plants rhizomatous ______________________________________________ 13. B. mendumiae

2b. Plants creeping or decumbent, not rhizomatous ____________________________________ 3

3a. Petioles 0.5–2 cm long _____________________________________________ 17. B. sidolensis

3b. Petioles 3–16 cm long ____________________________________________________________ 4

4a. Adaxial leaf lamina with sparse indumentum of bristly hairs between the veins; female flower 2-tepalled ______________________________________________________ 20. B. willemii

4b. Adaxial leaf lamina glabrous; female flowers 5-tepalled _____________________________ 5

5a. Petioles moderately hairy with white hairs; veins hairy on the abaxial leaf lamina surface; male flowers with 19–21 stamens ____________________________ 3. B. carnosa

5b. Petioles glabrous except for very sparse indumentum on the joint of the petiole and lamina; abaxial surface of leaf lamina glabrous; male flowers with 75–77 stamens 7. B. gemella

6a. Male and female flowers occurring together in bisexual inflorescences and open at the same time ________________________________________________________________________ 7

6b. Female inflorescences or solitary flowers separated from the male inflorescences by at least one internode, protogynous _________________________________________________ 10

7a. Male flowers with four tepals, anther connectives projecting at the apex ____________ 8

7b. Male flowers with two tepals, anther connectives not projecting at the apex 15. B. rieckei

8a. Female flowers or fruit with persistent bracteoles; fruit dehiscent, a dry capsule, fruit wings well developed and unequal _________________________________________________ 9

8b. Female flowers or fruit without persistent bracteoles; fruit indehiscent, fleshy, fruit wings poorly developed or sometimes wingless __________________________ 1. B. aptera

9a. Plant hairy, leaf lamina ovate, apex acuminate __________________________ 22. B. hirtella

9b. Plant glabrous, leaf lamina broadly ovate to suborbicular, leaf lamina apex rounded 21. B. cucullata

10a. Leaves elliptic, venation pinnate __________________________________________________ 11

10b. Leaves ovate to elliptic or broadly ovate, venation palmate-pinnate _________________ 14

11a. Female inflorescence peduncle <1 cm long; female flower pedicels 3–7 mm long __ 12

11b. Female inflorescence peduncle> 1 cm and up to 2 cm long; female flower pedicels 8–12 mm long ____________________________________________________ 8. B. hispidissima

12a. Leaf lamina length-to-width ratio> 3:1, glabrous or sparsely hairy with bristly hairs between the veins, abaxially hairy on the veins only; female flower pedicel 3–4 mm long; ovary glabrous to glabrescent _______________________________________________ 13

12b. Leaf lamina length-to-width ratio <3:1, densely hairy on both surfaces, hairs sometimes branched; female flower pedicel c. 7 mm long; ovary densely hairy 12. B. masarangensis

13a. Leaf lamina margin serrate or double serrate to shallowly lobed, leaf lamina adaxially with distinctly sunken primary and secondary veins; male flower tepals 5–6 × 6–7 mm, stamens 21–25 ___________________________________________________ 16. B. rolandfadlii

13b. Leaf lamina margin entire to serrulate in the distal third of the lamina, veins on adaxial lamina surface not sunken; the male flowers with larger tepals (10–13 × 10–11 mm) and more stamens (c.40) ___________________________________________ 5. B. cuneatifolia

14a. Male inflorescences not subumbellate, showing dichasial or monochasial branching with at least the basal internodes> 1 mm long ____________________________________ 15

14b. Male inflorescences subumbellate, i.e. consisting of strongly condensed cymes with internodes <1 mm long __________________________________________ 2. B. capituliformis

15a. Female flowers with 5 tepals _____________________________________________________ 16

15b. Female flowers with 4 tepals _____________________________________ 4. B. chiasmogyna

16a. Stem hairy _______________________________________________________________________ 17

16b. Stem glabrous ___________________________________________________________________ 20

17a. Stem densely hairy with bristle or pilose hairs (> 0.5 mm long); male inflorescence a thyrse with monochasially or dichasially branching partial inflorescences; male flower tepals 5–11.5 × 6–12 mm ________________________________________________________ 18

17b. Stem sparsely hairy with short bristle hairs (<0.5 mm); male inflorescence a compound thyrse with multiple lateral branches, each with multiple cymose partial inflorescences; male flower tepals minute (4–5 × 4–5 mm), broadly ovate to suborbicular _______________________________________________________ 18. B. sojolensis

18a. Plant covered with white hairs; male flower tepal margin entire, not ciliate; female flower tepals ovate; ovary glabrous _______________________________________________ 19

18b. Plant covered with crimson hairs; male flower tepal margin ciliate; female flower tepals obovate; ovary hairy _______________________________________________ 6. B. gambutensis

19a. Male inflorescence a thyrse composed of up to 4 lateral cymose partial inflorescences, each monochasially branching; female inflorescence or infructescence with short peduncle (1–2 mm long) ___________________________________________ 14. B. pitopangii

19b. Male inflorescence a thyrse composed of up to 6 lateral cymose partial inflorescences, each dichasially branching; female inflorescence with longer peduncle (5–10 mm long) 19. B. strachwitzii

20a. Infructescence peduncle 10–20 mm long ________________________ 11. B. macintyreana

20b. Infructescence peduncle <5 mm long ____________________________________________ 21

21a. Fruit pendulous on thin pedicel, fruit wings cuneate at base and truncate or subtruncate at the apex; seed-bearing part cylindrical ___________________ 10. B. kinhoi

21b. Fruit pedicel deflexed, fruit wings rounded at base and truncate at the apex; seed-bearing part ellipsoid __________________________________________ 9. B. insularum