Alangium

Dewilde, W. J. J. O. & Duyfjes, B. E. E., 2017, Taxonomy of Alangium section Conostigma (Alangiaceae), Blumea 62 (1), pp. 29-46 : 29-30

ALANGIUM SECT. CONOSTIGMA

1. Lamina (sub)circular, glabrous. — Borneo ( Sarawak)....................................... 2. A. circulare

1. Lamina usually longer than broad, glabrous or hairy.... 2

2. Lamina cordate at base. Venation 3(–5)-plinerved at base .. ... ... ... ... ... .. ... ... ... ... ... ... ... ... .. 3

2. Lamina subcordate, rounded or attenuate at base. Venation pinnate....................................... 4

3. Corolla in bud 18–20 mm long. Lamina glabrous or short hairy below. ― Peat swamp forest..... 3. A. denudatum

3. Corolla in bud 10–15 mm long. Lamina conspicuously long-hairy below. ― Dry land forest............ 14. A. nobile

4. Lamina asymmetric at base. Calyx teeth distinct. Style and lower portion of filaments densely hairy. ― Peat swamp forest, Borneo ( Brunei, Sarawak)....... 5. A. havilandii

4. Lamina not or weakly asymmetric at base. Calyx limb (sub)- truncate or with low teeth. Style and lower portion of filaments hairy or glabrous............................... 5

5. Twigs, leaf bud(s), inflorescence, flowers and fruit all conspicuously hairy; hairs stellate-dendroid, 0.3‒0.5(‒1) mm long............................. 10. A. maliliense

5. Twig, leaf bud, inflorescences, flowers and fruit glabrous or hairy; hairs not stellate, to 0.5 mm long.............. 6

6. Petiole long, 2‒4.5 cm long. Twigs towards apex conspicuously rusty-hairy. Fruit conspicuously hairy. ― Papua New Guinea (Morobe Prov.)...........19. A. subcordatum

6. Petiole shorter. Twigs, flowers, fruit glabrous or hairy.. 7

7. Plant from Indochina or W Malesia (incl. Philippines). Filaments ± hairy. Leaves generally drying greenish or brown........................................... 11

7. Plant from E Malesia (Sulawesi, Moluccas, New Guinea) or the Pacific (Solomon Isl.). Filaments (sub)glabrous or hairy. Leaves often drying blackish or leaden grey.... 8

8. Corolla in bud (12–) 15–20 mm long. Filaments at apex densely hairy..................13. A. minahassicum

8. Corolla in bud 8‒9 mm long. Filaments glabrous or hairy9

9. Hairs obvious, c. 0.3 mm long, rendering twigs, inflorescence and flowers hairy. Twigs c. 5 mm diam........................................ 9. A. ledermannii

9. Hairs inconspicuous, c. 0.1 mm long, rendering twigs, inflorescences and flowers (sub)glabrous. Twigs 2–4 mm diam....................................... 10

10. Petals glabrous inside. Filaments glabrous. ― New Guinea............................... 6. A. hollrungii

10. Petals hairy inside. Filaments hairy. ― Solomon Isl.....................................17. A. plumbeum

11. Twigs stout, 5–10 mm diam.................... 12

11. Twigs more slender, 1.5–5 mm diam............. 13

12. Buds usually acute at apex. Fruit 20–30 mm long, fewer and less deeply ribbed, or hardly ribbed. Lamina drying purplish below................... 4. A. ebenaceum

12. Buds usually blunt. Fruit (25‒) 30–40 mm long, conspicuously, deeply (10–)12(–14)-ribbed. Lamina not drying purplish below....................... 18. A. ridleyi

13. Plant (including leaf bud) almost completely glabrous (some sparse, minute downy scales 0.1 mm long on leaf bud excepted). Twigs slender, 2 mm diam; leaves small, 15 cm long or less. ― Dry land forest northern Borneo................................... 8. A. kayuniga

13. Plant minutely or obviously hairy, at least on leaf bud and apex of young twigs, hairs either c. 0.1 mm long or hairs 0.1–0.5(–1) mm long. Twigs slender or thicker, to 5 mm diam....................................... 14

14. Apex of twigs, leaf bud, inflorescences, and flowers densely (appressed) hairy, hairs 0.3‒0.5(–1) mm long. Fruit round- ed at base, 15–20(–25) mm long, drying grey or brown (W Java, Sumatra, Peninsular Malaysia, Borneo), or fruit narrowed at base, 20–30 mm long, drying yellow-green (Borneo).................................... 15

14. Apex of twigs, leaf bud, inflorescences, and flowers minutely hairy, sometimes appearing as glabrous; hairs (much) less than 0.3 mm long. Fruit ± rounded at base..... 17

15. Inflorescences (sub)sessile, or with peduncle to 0.3(–1) cm long. Fruit ovoid-ellipsoid, 15–20(–25) mm long. Flowers small, corolla in bud 8–10 mm long. — W Java, (E) Borneo.............................. 7. A. javanicum

15. Inflorescences peduncled. Fruit ± fusiform, narrowed at base, 20–30 mm long. Flowers longer, corolla in bud 12–17 mm long. — Borneo.......................... 16

16. Leaf bud in-curved, hairs longer, 0.5 mm long.........................................1. A. borneense

16. Leaf bud straight, hairs shorter, 0.2–0.3 mm long..................................... 12. A. mezianum

17. Twigs stout, 3–10 mm diam. Lamina large, 15–50 cm long, often drying purplish brown below.... 4. A. ebenaceum

17. Twigs more slender, 1.5–6 mm diam. Lamina not drying purplish brown below.......................... 18

18. Twigs pale, contrasting with blackish brown drying petioles and peduncle of inflorescences......... 16. A. pallens

18. Twigs, petioles and peduncle brown.............. 19

19. Aspect of specimen less robust: twigs 1.5–4 mm diam; lamina 8–18 cm long, with 6–10 veins at each side; corolla in bud 8–14 mm long; fruit 2–4 per infructescence, 20–25 mm long. — Widespread in W Malesia.... 11. A. meyeri

19. Aspect of specimen more robust: twigs 2–4(–5) mm diam; lamina 12–25(–35) cm long, with 8–15 veins at each side; corolla in bud 12–15 mm long; fruit 1–3 per infructescence, 20–30(–35) mm long. ― Widespread in W Malesia, but not in the Philippines............... 15. A. oblongum