Polyalthia, Blume, 1830

Turner, Ian M. & Utteridge, Timothy M. A., 2016, Whither Polyalthia (Annonaceae) in Peninsular Malaysia? Synopses of Huberantha, Maasia, Monoon and Polyalthia s. s., European Journal of Taxonomy 183, pp. 1-26 : 12-13

Key to the species of Polyalthia

1. Inflorescences cauliflorous, ramiflorous or axillary ........................................................................... 2 – Inflorescences subopposite leaves ..................................................................................................... 8

2. Flower pedicel 2–5(–7) mm long; petals narrowly linear (generally more than 10 times long as broad). Monocarps subsessile (stipes to 5 mm long) ......................................................................... 3

– Flower pedicel (6–) 10–30 mm long; petals not narrowly linear (rarely to 10 times as long as broad). Monocarps stipitate (stipes 10 mm long or more)............................................................................... 6

3. Subshrub to 30 cm tall. Petals not exceeding 3 cm long ....................................................... P. pumila – Tree to 6 m or more tall. Petals to 5 cm or more long ........................................................................ 4

4. Petals 5 mm wide or more. Monocarps densely brown woolly hairy ........................... P. cinnamomea – Petals 2–5 mm wide. Monocarps pubescent, becoming glabrous with maturity ............................... 5

5. Inflorescences mostly on trunk and branches. Twigs persistently brown hairy. Sepals 15–17 mm long. Monocarps 2 cm wide ........................................................................................... P. stenopetala

– Inflorescences mostly among leaves. Twigs becoming glabous with age. Sepals 7 mm long. Monocarps less than 1 cm wide ................................................................................... P. angustissima

6. Inflorescences mostly cauliflorous, or if among leaves then pedicel generally 20 mm long or more ..... .......................................................................................................................................... P. cauliflora – Inforescences not cauliflorous, flower pedicel to 12 mm long .......................................................... 7

7. Leaves drying grey. Flower pedicel more than 1 mm wide, widening distally; petals 2–5 cm long. Monocarps more or less cylindrical, 6–7 mm diameter; stipe c. 1 mm diameter ................. P. lateritia

– Leaves drying brown or grey-brown. Flower pedicel c. 0.5 mm wide; petals less than 1 cm long. Monocarps more or less globose, c. 15 mm diameter; stipe c. 2 mm diameter..................... P. obliqua

8. Leaves with many lateral nerves (at least 18 pairs); lamina bullate .................................................. 9 – Leaves with up to 17 pairs of lateral nerves; lamina not bullate ...................................................... 10

9. Twigs villose. Base of leaf auriculate or cordate, often extending below twig ..................... P. bullata – Twigs glabrous or hairy, not villose. Base of leaf not auriculate or cordate, never extending below twig ............................................................................... P. pakdin I.M.Turner & Utteridge sp. nov.

10. Leaves narrowly elliptic or lanceolate to 2.5 cm wide, apex long acuminate ..................... P. dumosa – Leaves generally more than 2.5 cm wide, apex not long acuminate ............................................... 11

11. Leaf apex obtuse. Branchlets with thick corky bark. Flower pedicel slender (5–25 mm long, <1 mm thick) ................................................................................................................................. P. suberosa

– Leaf apex generally acute to acuminate. Branchlets not corky-barked. Flower pedicels generally shorter and/or thicker ....................................................................................................................... 12

12. Flowers subsessile (pedicel to 2 mm long) ..................................................................................... 13 – Flowers distinctly pedicellate (pedicel 5 mm long or more) ........................................................... 14

13. Leaves glabrous; elliptic-lanceolate; apex blunt. Petals coriaceous, fleshy ...................... P. parviflora – Leaves pubescent beneath; lanceolate; acuminate. Petals thin .......................................... P. hirtifolia

14. Twigs, leaf undersides, flowers and fruits furry .......................................................... P. chrysotricha – Twigs, leaf undersides, flowers and fruits glabrous or hairy but not all furry .................................. 15

15. Leaves generally with 10 or fewer pairs of lateral nerves. Flower pedicel to 5 mm long. Monocarps to 6, stipe shorter than seed-bearing portion ................................................................ P. brunneifolia

– Leaves with 12 or more pairs of lateral nerves. Flower pedicel 5 mm or more long. Monocarps 10 or more, stipe generally longer than seed-bearing portion .................................................................. 16

16. Petals relatively thin; sparsely hairy outside. Stipe of monocarps c. 0.5 mm thick ................. P. socia – Petals relatively thick and leathery; densely hairy outside. Stipe of monocarps c. 1 mm thick ...... 17

17. Pedicel 3–6 cm long .......................................................................................................... P. oblonga – Pedicel to 1 cm long ....................................................................................................... P. motleyana