KEYS TO MACARANGA AND MALLOTUS 157 XI. Keys to the taxa of Macaranga and Mallotus (Euphorbiaceae) of East Kalimantan (Indonesia) J.W.F. Slik Rijksherbarium/Hortus Botanicus, P.O. Box 9514, 2300 RA Leiden, The Netherlands (e-mail: [email protected]) Summary Keys mainly based on vegetative characters are given to the 27 taxa of Macaranga and 20 of Mallotus known from or reported for East Kalimantan, Borneo, Indonesia. Introduction Species ofthe generaMacaranga Thou, and Mallotus Lour. (Euphorbiaceae) often form a characteristic part of secondary vegetations in Malesia. Many are among the first colo- nizers ofdisturbed vegetations. A considerable number can also be found in late secon- dary vegetations and the understorey of primary forests. This wide ecological scope and the more or less well-defined ecological preferences of the various species make them potentially very useful for recognizing the disturbance history of a forest. A comprehensive key to the species is still much in need. It should emphasize vegeta- tive characters in order to recognize sterile specimens. Those presently available for East Kalimantan are either outdated (Pax & Hoffmann, 1914), incomplete (KeBler & based the of Sidiyasa, 1994), or largely on availability both flowering and fruiting mate- rial (Airy Shaw, 1975). collections in 2 of The following keys are based on present L, but species Macaranga reported for the area by Airy Shaw (1975), KeBIer & Sidiyasa (1994), and KeBIer et al. (1995) were absent there. These have been noted as 'doubtful'. Still, they had to be included for completeness' sake. Generative characters have only been addedwhen iden- tification is impossible otherwise. Please note that these keys were made specifically for East Kalimantan. Identification of plants from outside that area may not be possible, even when the species have been included here. Short notes on the ecology, distribution, and habit of the species are given, but are based on information on the labels of East Kalimantan specimens, only. The distribution ranges have been indicated only roughly (see Map 1). KEY TO THE GENERA 1 Indumentumsimple to absent. Twigs solid to hollow (ant-inhabited). Leaves alternate, often peltate, often lobed,base above sometimes with few glands. Inflorescences most- ly branched. Male flowers completely surrounded by bracts. Bracts sometimes fim- briate. Stamens 30, anthers 3- 4-celled, thecae up to c. clearly or apicifix, opening apically. Styles usually free, unbranched. Fruits 2-6-locular, sometimes spiny ... Macaranga 158 FLORA MALESIANA BULLETIN 12(4), 1998 - Indumentum stellate to simple to absent. Twigs solid. Leaves alternate or opposite, sometimes peltate, rarely lobed, base above usually with few glands. Inflorescences mostly unbranched. Male flowers not surrounded by bracts. Bracts never fimbriate. Stamens up to c. 150, anthers 2-celled, basi- to dorsifixed, thecae opening extrorsely. Style apically splitting into (2 or) 3 (or 4) stigmas. Fruits (2- or) 3- (or 4-)locular, mostly spiny Mallotus Map 1. East Kalimantan. The main collecting areas are roughly indicated: Balikpapan. Berau. Kutai, Tarakan. MACARANGA Shrubs to small trees to trees up to 30 m high, dioecious. Indumentum simple. Bark sometimes prominently hooped (rings surrounding the stem). Wood soft. Twigs some- times hollow and ant-inhabited(small openings), sometimes whitish-glaucous. Stipules small and narrowly triangular to very large and ovate to rounded, sometimes recurved and forming an enclosed hollow inhabitedby ants. Leaves alternateto spirally arranged, often small to very large, blades peltate, sometimes 3(-5)-lobed, pinnate to basally KEYS TO MACARANGA AND MALLOTUS 159 triplinerved to palmatinerved, sometimes with basal glands above, often gland-dotted below. Inflorescences axillary to rarely sub-terminal. Male inflorescences mostly branch- ed; bracts large, surrounding the flowers, sometimes fimbriate; flowers 2-150 per node, sepals 2-4, stamens 1-30, anthers 3- or 4-celled, apicifix, disc rarely present, pistil absent. Female inflorescences usually branched; bracts persistent to caducous; flowers 1 to several per node, calyx short, ovary 1-6-locular, styles long to short, usually free and unbranched. Fruit a leathery to berry-like capsule, smooth to spiny to horned, some- times with conspicuous glandular patches, dehiscing into bivalved parts. Seeds black to red. KEY TO THE TAXA 1 Twigs solid 2 - Twigs hollow (often ant-inhabited) 29 2 Leaves pinninerved 3 - Leaves at base triplinerved to palmatinerved 10 3 Vegetative parts completely glabrous 4 - Twigs, petioles, and/or leaf below hairy 5 4 Leaves whitish glaucous below. Basal nerves of equal length or longer than those higher along the midrib 5. Macaranga conifera - Leaves not whitish glaucous below. Basal nerves shorter than those higher along the midrib 17. Macaranga lowii var. kostermansii 5 Vegetative parts with hairs longer than 1 mm 6 - Vegetative parts with hairs always shorter than 1 mm 7 6 Leaves 5-7 cm long, secondary nerves conspicuous above. Pedicels up to 1 cm long 9. Macaranga fulva - Leaves 7-17 cm long, secondary nerves inconspicuous above. Pedicels 1.5-3 cm long 23. Macaranga repando-dentata 7 Basal nerves shorter than those along the midrib 8 - Basal nerves of equal length or longer than those along the midrib 9 8 Twigs and petioles densely hairy. Petioles usually shorter than 2 cm 4. Macaranga brevipetiolata - Twigs and petioles mostly sparsely hairy. Petioles usually longer than 2 cm 16. Macaranga lowii var. lowii 9 Leaves below conspicuously whitish glaucous, velvety hairy, secondary nerves not raised 5. Macaranga conifera - Leaves below not glaucous, not velvety hairy, secondary nerves clearly raised ... 6. Macaranga costulata 10 Leaves peltate 11 - Leaves not peltate 22 11 Leaves not lobed 12 - Leaveslobed 18 160 FLORA MALESIANA BULLETIN 12(4), 1998 12 Petiole insertion more than 1.4 cm from the base ofthe blade.Leaves above without glands near petiole insertion 13 - Petiole insertion less than 1.4 cm from the base of the blade. Leaves above some- times with 2 glands near petiole insertion 16 13 Leaf below glabrous to sparsely hairy on the main nerves, always with numerous punctate glands 14 - Leaves below densely hairy all over, with few to numerous glands 25. Macaranga tanarius 1 4 Leaves less than 11 below covered rarely cm wide, densely by yellow punctate glands. Capsules dry 15 - Leaves never more than 11 cm wide, below sparsely, rarely densely covered by yel- low punctate glands. Capsules berry-like 21. Macaranga puncticulata 15 Stipules tough (leathery when dry). Leaves leathery when dry, below glaucous, sec- ondary nerves not raised 22. Macaranga recurvata - Stipules thin (papery when dry). Leaves papery when dry, below not glaucous, sec- ondary nerves raised 25. Macaranga tanarius 16 Leaves below raised (12). not glaucous, not velvety hairy, secondary nerves clearly 17 - Leaves below whitish conspicuously glaucous, velvety hairy, secondary nerves not raised 5. Macaranga conifera 17 Leaves above with two near insertion 6. costulata glands petiole .... Macaranga - Leaves above without two glands near petiole insertion .. 8. Macaranga endertii 18 (11). Stipules up to 1.5 cm long, broadly ovate to ovate, apex rounded to acuminate to acute, persistent to caducous, alive on living plant. Leaves shorter than 30 cm . 19 - 4 dead dried Stipules up to cm long, ovate, apex acute, persistent, and out on living plant. Leaves usually longer than 30 cm 10. Macaranga gigantea 1 9 often whitish rounded to Twigs glabrous, glaucous. Stipules broadly ovate, apex acu- minate, rarely acute. Petioles rarely hairy. Leaves often with an emarginate base, blade deeply 3-lobed, below glabrous to hairy 20 - Twigs hairy, not whitish glaucous. Stipules ovate, apex acute. Petioles hairy. Leaves with a rounded to truncate base, blade 3- (or 5-)lobed, below shallowly hairy .... 7. Macaranga depressa forma strigosa 20 than leaves Stipules caducous, rarely persistent (if so below velvety hairy). Leaves below glabrous to velvety hairy 21 - Stipules persistent (present with all the leaves!). Leaves below glabrous 11. Macaranga hosei 21 whitish for often Twigs conspicuous glaucous, openings ants present. Stipules ovate with clearacuminate to acute apex. Leaves often with large protruding glands along the margin of the base, leaves below mostly glabrous or with sparse hairs, rarely vel- vety 19. Macaranga pearsonii - Twigs mostly not whitish glaucous, without openings for ants. Stipules broadly ovate with rounded to acuminate apex. Leaves without large protruding glands along the margin of the base, leaves below velvety hairy 20. Macaranga pruinosa KEYS TO MACARANGA AND MALLOTUS 161 22 (10). Leaves not lobed 23 - Leaveslobed 26 23 Leaves above glabrous, rarely sparsely hairy on the nerves 24 - 26. Leaves above hairy all over Macaranga trichocarpa 24 Twigs, petioles, and leaves below with sparse to numerous hairs 25 - 5. conifera Vegetative parts glabrous Macaranga 25 Leaves below conspicuously whitish glaucous, velvety hairy, secondary nerves not raised 5. Macaranga conifera - raised Leaves below not glaucous, not velvety hairy, secondary nerves clearly . .. 6. Macaranga costulata base cordate 27 26 (22). Leaves deeply 3-lobed, above never hairy, deeply - Leaves shallowly 3-lobed (cusped), above hairy, base acute to rounded to slightly cordate 26. Macaranga trichocarpa 27 Stipules caducous (if persistent then leafbelow velvety hairy). Leaves below gla- brous to velvety hairy 28 - Stipules persistent