Malesian Euphorbiaceae Descriptions

88. PTYCHOPYXIS (Euphorbiaceae)

E. Stoops & P.C. van Welzen

Stoops, E. & van Welzen, P.C. 2013. A revision of Ptychopyxis (Euphorbiaceae) in South-East Asia. Nordic Journal of Botany 31: 94–112.

Goto on this page:

Genus description

Key to the species

Species descriptions

Excluded species

Ptychopyxis Miq.

    Ptychopyxis Miq., Fl. Ned. Ind., Eerste Bijv. (1861) 402; Hook.f., Hooker’s Icon. Pl. 18 (1887a) tab. 1703; Fl. Br. India 5 (1887b) 454; Ridl., Fl. Malay Penins. 3 (1924) 294; Pax & K.Hoffm. in Engl. & Harms, Nat. Pflanzenfam. ed. 2, 19c (1931) 230; Croizat, J. Arnold Arbor. 23 (1942) 47; Airy Shaw, Kew Bull. 14 (1960) 363; Kew Bull. 16 (1963) 347; Backer& Bakh.f., Fl. Java 1 (1963) 479; Airy Shaw, Kew Bull. 26 (1972a) 327; Whitmore, Tree Fl. Malaya 2 (1973) 126; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 188; Kew Bull., Addit. Ser. 8 (1980) 197; Kew Bull. 36 (1981) 340; Alphab. Enum. Euphorb. Philip. Isl. (1983) 43; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 77; Govaerts et al. (2000) 1379; Radcl.-Sm., Gen. Euphorbiacearum (2001) 172, Fig. 20; Welzen & Chayam., Fl. Thailand 8 (2007) 512; Stoops & Welzen, Nordic J. Bot. 31 (2013) 95; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 125. — Ptychopyxis Miq. subgen. Ptychopyxis: Airy Shaw, Kew Bull. 14 (1960) 365. — Type: Ptychopyxis costata Miq.

    Clarorivinia Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii (1914) 17. — Type: Clarorivinia chrysantha (K.Schum.) Pax & K.Hoffm. [= Ptychopyxis chrysantha (K.Schum.) Airy Shaw]. 

Treelets to trees, dioecious. Indumentum simple, villous, ferrugineous, on vegetative and generative parts, usually two layers, short hairs and longer, sharp ones, both glabrescent, especially the longer ones. Stipules absent, but axillary bud scales may resemble stipules. Leaves alternate, clustered at the apex of branches to scattered along the branches, simple; petiole basally and apically pulvinate, mostly cylindrical; blade ovate to obovate, symmetric, coriaceous, margin entire, often somewhat undulate, usually partly revolute, both surfaces usually with extrafloral nectaries, partly hairy, especially the midrib, more so on the lower surface; venation pinnate, secondary veins looping near the margin and connecting to the vein above, tertiary veins scalariform. Inflorescences mainly racemes, sometimes with short side-branches (paniculate racemes) to seldom panicles; staminate flowers in groups per node, pistillate flowers generally single; bracts to side-branches, fascicles and flowers narrow-triangular, completely hairy; pedicels with an abscission zone and bracts/bracteoles up to the abscission zone; bracteoles present, but often not distinctly different from bracts. Flowers 3–5-merous, unisexual, pedicellate; calyx lobes valvate, basally or partly connate, coriaceous; petals absent. Staminate flowers: stamens 35–65, filaments tapering towards the apex, apically bent, anther dorsi-basifixed, connective broadly triangular with on one side 4 thecae of which the 2 inner, upper ones smaller and the 2 outer, lower ones larger; disc consisting of many glands among the stamens with apical long hairy enations; pistillode absent. Pistillate flowers: staminodes occasionally present, placed outside the disc; disc an indistinct, basal ring around the pistil, densely hairy; ovary 1–5-locular, superior, longitudinally ribbed, velutinous; ovules 1 per locule; style velutinous, stigmas not apically split. Fruits capsules, densely hairy, often grooved or ribbed, sometimes apically beaked, sometimes with soft appendages; calyx and usually the stigmas persistent, wall woody. Seeds oblong, covered by a thin, hyaline sarcotesta.

    Distribution — Eleven species ranging from Southeast Asia main land throughout W. Malesia and New Guinea.

Key to the species

1. Ptychopyxis arborea (Merr.) Airy Shaw

    Ptychopyxis arborea (Merr.) Airy Shaw, Kew Bull. 14 (1960) 369; Kew Bull. 16 (1963) 347; W.Meijer, Bot. News Bull. Forest Dept. Sabah 7 (1967) 53; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 188; Stoops & Welzen, Nordic J. Bot. 31 (2013) 97, Fig. 1a, b, 2f, 3. — Mallotus arboreus Merr., Pl. Elmer. Born. (1929) 159. — Ptychopyxis arborea (Merr.) Airy Shaw var. arborea: Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 188. — Type: Elmer 20854 (holo UC?; iso L), British North Borneo, Elphinstone Prov., Tawao.

Trees, 10–35 m tall, dbh 7–70 cm, bole 5–20 m high. Outer bark blackish brown to red-brown, smooth, not fissured, not peeling; inner bark yellow; sapwood and heartwood white. Leaves: petiole 1–10.5 cm long, apically with transverse ridges adaxially; blade elliptic (to obovate), 6.5–24.5 by 3–12 cm, length/width ratio 2–2.2, coriaceous, base attenuate, usually with a pair of glands abaxially, margin (rarely serrulate to) serrate (to deeply serrate, teeth 2–3 mm long, the tip apiculate, in some collections of Sulawesi), distance between teeth 1.4–3 cm (2–4 cm in some places on Sulawesi), apex acute to cuspidate, upper surface dull when dry; venation indistinct above, prominent beneath, nerves 5–11 pairs. Staminate inflorescences racemose, fascicles up to6 per axil, 1–5.5 cm long, axillary and/or cauliflorous; bracts 3, triangular, apex serrate, central one larger, 1–1.5 by 0.7–1.5 mm, 2 smaller lateral bracteoles c. 0.25 by 0.25 mm. Staminate flowers 1–6.5 by 2–4 mm, yellow; pedicel 0.2–4 by 0.2–1 mm; calyx lobes 2–3.5 by 1–2 mm, margin and apex serrate; stamens 7–29, in 3 whorls, filaments 0.25–1.5 mm long, anthers 0.25–1.25 by 0.25–1 mm. Pistillate inflorescences solitary, 1–1.6 cm long; bracts 3,  triangular, central one large, c. 1 by 1 mm, 2 smaller lateral bracteoles c. 0.5 by 0.5 mm. Pistillate flowers 3–3.5 by c. 1 mm; pedicel 1.5–2 by c.1 mm long; calyx lobes 1.5–2 by 1–1.5 mm, glands at the union of the basal two lobes, margin and apex entire; ovary 1.2–1.8 by c. 1 mm, locules 3 or 4; stigmas lobes pulvinate, flat. Fruits pyriform, 0.8–1.7 cm in diameter, young light green, mature reddish; pedicel 0.6–2 cm long; remnants of stigmas absent. Seeds globose, one per fruit, 1–1.3 by 0.7–1 cm.

    Distribution — Malesia: Endemic throughout Borneo. 

    Habitat & Ecology — Mixed dipterocarp forests, secondary forest, often in forest remnants, on hill slopes and ridges and along streams. Soil: marshy to dry, clay, (coral) limestone (with sand of loam); bedrock: basalt or sandstone. Altitude: 15–600 m. Flowering: March to April, June to July, September to October; fruiting: April to October and December.

    Uses — Fruits edible (which part not indicated, probably sarcotesta).

    Vernacular names — Borneo: Kalimantan: Lebui (Bassap Dayak), Mardjilawat, Perupak batu; Sabah: Kamanyan (Kedayan), Luagan lagan (Kedayan); Sarawak: Bantas (Iban).

    Notes — 1. The other variety, var. cacuminun Airy Shaw is a synonym of P. javanica.

    2. This species closely resembles P. kingii. The latter has a wider distribution (Malay Peninsula, Sumatra, and overlap only in Borneo). The easiest character is the presence (P. kingii) or absence (P. arborea) of a style, resulting in fruits without and with persistent stigmas, respectively. Another difference (see key) is in indumentum of the petioles. The sizes of the perianth segments may also show differences between the species, but too few flowering specimens could be examined to be certain.

2. Ptychopyxis bacciformis Croizat

    Ptychopyxis bacciformis Croizat, J. Arnold Arb. 23 (1942) 49; Airy Shaw, Kew Bull. 14 (1960) 371; Kew Bull. 16 (1963) 348; Meijer, Bot. News Bull. Forest Dept. Sabah 7 (1967) 53; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 189. —  Koilodepas (‘Coelodepas’) sp.?: Merr., Pl. Elmer. Born., (1929) 156; Stoops & Welzen, Nordic J. Bot. 31 (2013) 97, Fig. 2c, 4. — Type: Elmer 21524 (holo A, n.v.; iso L), British North Borneo, Elphinstone Prov., Tawao.

    Ptychopyxis poilanei Croizat, J. Arnold Arbor. 23 (1942) 50; Airy Shaw, Kew Bull. 14 (1960) 372. — Type: Poilane 6398 (holo A; iso L, P n.v.), Indo-Chine, Annam, Nhatrang Prov., north of Nuh-hoa, eastern slopes of the “Massif de la Mère et de l’Enfant”.

    Ptychopyxis philippina Croizat, J. Arnold Arbor. 23 (1942) 49; Airy Shaw, Kew Bull. 14 (1960) 372; Alphab. Enum. Euphorb. Philip. Isl. (1983) 43. — Syntypes: Wenzel 2710 (A), Philippines, Mindanao, Surigao; Wenzel 3501 (A), Philippines, Mindanao, Surigao.

    Ptychopyxis triradiata Airy Shaw, Kew Bull. 14 (1960) 366; Whitmore, Tree Fl. Malaya 2 (1973) 127; Radcl.-Sm., Gen. Euphorb. (2001) 172, Fig. 20j. — Type: M. Shah 293 (holo K; iso L), Malay Peninsula, Perak, Bota Kiri Forest Reserve, near Ipoh.

Trees, up to 38 m high, diameter  up to 40 cm; nodes not thickened; flowering branches 0.8–2.5 mm thick; axillary buds 1 or 2 to several, collateral to bundled. Indumentum golden to brown. Outer bark greyish to brownish to brownish grey, smooth (to superficially fissured), c. 0.5 mm thick; inner bark reddish to brownish red to brown or pale yellowish outwards to pink-yellowish inward, granular, 3–6 mm thick; sapwood white to light brown, soft. Leaves scattered to clustered at apex; petiole 0.7–3.1 cm long, diameter 0.6–2 mm, transversely grooved, densely hairy, upper pulvinus 1.5–2.6 mm diameter; blade elliptic to obovate, 5.9–17.6 by 1.4–7.4 cm, length/width ratio 2.4–4.2, usually remaining green when dry, base obtuse to acute, margin entire, apex emarginate to cuspidate, upper and lower surface green, lower surface slightly lighter, glabrous to sparsely hairy, midrib more densely hairy, extrafloral nectaries on lower surface 0–2 at base, along midrib and between veins none to occasionally to frequently, apically absent, veins 7–15. Staminate inflorescences paniculate racemes, up to 16 cm long, pale green; bracts 1.2–2.7 by 0.4–0.7 mm. Staminate flowers green to yellow, 4–4.5 by 2.5–5.6 mm; calyx 3-lobed, green, lobes basally fused, triangular to ovate to elliptic, 1.9–3.1 by 1.4–2.9 mm, recurved, outside densely hairy, inside (occasionally) hairy; filaments 1–2 by 0.1–0.2 mm, white; anthers 0.5–0.9 by 0.2–0.6 mm, connective triangular to rectangular, with an apical appendage; disc glands small, round to strap-like. Pistillate inflorescences up to 4 cm long, single. Pistillate flowers unknown; young fruits with calyx pale brown; ovary brown-green stigmas green. Infructescences up to 10.5 cm long; bracts 2.3–5 by 0.7–1 mm. Fruits ovoid with 1–4 shallow lobes, diameter 9.5–20.5 mm, olive to bright yellow to orange, without appendages; disc without triangular appendages; wall 0.2–1.1 mm thick, outside wrinkled; columella present; locules 3 or 4; stigmas 3 or 4, persistent. Seeds ovoid, often with ridge on top, diameter 8.5–12.1 mm; sarcotesta white, sweet.

    Distribution — Vietnam, Malesia: Malay Peninsula, Sumatra, Borneo, Philippines.

    Habitat & Ecology — Primary dipterocarp lowland forest, peat swamp forests, disturbed areas, on hillsides, ridges, along streams. Soil: sand, clay, blackish soil; bedrock: granodiorite. Altitude: Up to 500 m. Flowering: March-June, September-December; fruiting: February, June, August-September, November.

    Uses  Sarcotesta edible.

    Vernacular names — Borneo: Sabah: Kerosid; Sarawak: Bantas. Philippines: Apanang.

    Note — When dried the leaves usually remain green, which distinguishes it from P. javanica. Both species are vegetatively quite similar.

3. Ptychopyxis caput-medusae (Hook.f.) Ridl.

    Ptychopyxis caput-medusae (Hook.f.) Ridl., Fl. Malay Penins. 3 (1924) 295; Airy Shaw, Kew Bull. 14 (1960) 366; Whitmore, Tree Fl. Malaya 2 (1973) 127; Radcl.-Sm., Gen. Euphorb. (2001) 172, Fig. 20K; Stoops & Welzen, Nordic J. Bot. 31 (2013) 101, Fig. 2a, 5. — Mallotus ? caput-medusae Hook.f., Fl. Brit. India 5 (1887b) 443. — Lectotype (designated by Stoops & Welzen 2012): Maingay KD 1443 (K), [Malaysia,]  Malacca. Former sntypes: Griffith s.n. (K), Mallacca; King’s collector s.n. (K), Malaysia, Perak; Maingay KD 1426 (K), Malacca; Maingay KD 1443 (K), Malacca.

Trees, up to 30 m high, diameter 68 cm; bole fluted or with buttresses to 75 cm high; nodes not thickened to thickened; flowering branches 1.0–4.5 mm thick; axillary buds single. Outer bark grey to grey-brown, slightly hoop-marked, smooth to apically minutely flaking to show red-brown underlayer, to scurfy to scaly; inner bark red to brown with radial pale lines, thin, firm, granular outwards, fibrous inwards; sapwood cream. Leaves: petiole 1.4–3.9 cm long, diameter 1.9–2.6 mm, densely hairy, upper pulvinus 3–3.5 mm thick; blade elliptic, 15.8–24.3 by 6.7–9.7 cm, length/width ratio 2.4–2.5, base rounded to acute, margin entire, undulate, apex retuse to acuminate, upper surface glabrous to hairy, midrib more densely so; lower surface hairy on complete venation, midrib densely hairy, extrafloral nectaries 2 at base, along midrib frequently to none, between veins occasionally, apically absent, veins 10–14 per side. Staminate inflorescences racemes, up to 5.5 cm long; bracts c. 3.3 by 1 mm. Staminate flowers unknown, buds green. Pistillate inflorescences racemes, up to 3 cm long; bracts c. 2.2 by 1 mm. Pistillate flowers 7.8–8.1 mm long, diameter 5.7–8.2 mm, white; calyx 4- or 5-lobed, 3–3.1 mm high, lobes basally fused in lower 1/3, narrowly triangular, 2.9–4 by 1.2–2.1 mm, outside and inside densely hairy; ovary globular, 3.2–5.1 by 4.2–4.4 mm, covered with white spines, with 3 or 4 longitudinal ribs with reddish hairs, locules 3 or 4; style cylindrical to triangular, 1–1.9 mm long; stigmas 2.8–4.8 mm long, recurved, papillate above, velutinous underneath. Fruits globose, diameter 31–39.5 mm, grey-green to yellow-brown, 1 or 2 locules developed; wall 0.8–5.9 mm thick, covered with soft spines and an indumentum consisting of short and long, more or less stinging hairs; columella absent; stigmas persistent. Seeds not seen, reported to be black with white, fleshy sarcotesta. 

    Distribution — Malesia: Malay Peninsula..

    Habitat & Ecology — Primary and disturbed forests; bedrock: granite. Altitude: 300–500 m. Flowering: April; fruiting: April-May, September.

    Vernacular names — Medang jurnus (Ridley 1924); Rambai hutan (Whitmore 1973).

4. Ptychopyxis chrysantha (K.Schum.) Airy Shaw

    Ptychopyxis chrysantha (K.Schum.) Airy Shaw, Kew Bull. 14 (1960) 370; Kew Bull., Addit. Ser. 8 (1980) 197; Stoops & Welzen, Nordic J. Bot. 31 (2013) 102, Fig. 6. — Mallotus chrysanthus K.Schum. in K.Schum. & Hollr., Fl. Kaiser Wilhelmsland (1889) 78; K.Schum. & Lauterb., Fl. Deutsch. Schutzgeb. Südsee (1901) 14. — Clarorivinia chrysantha (K.Schum.) Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii (1914) 17. — Lectotype (designated by Airy Shaw 1960): Hollrung 756 (holo K), New Guinea, Territory of New Guinea (Kaiser Wilhelmsland), Augusta River [= Sepik River], Lagerberg der II Augusta-Station.

    Clarorivinia grandifolia Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xiv (1919) 13 (without description). — Type: Ledermann 7039 (B?, burnt), New Guinea, Kaiserin-Augusta Fluss Expedition, Camp 1 (Zuckerhut).

Trees, up to 28 m high, diameter 50 cm; buttresses up to 2 m high, out up to 0.7 m, thick up to 10 cm; nodes thickened; flowering branches 0.5–1.1 mm thick; axillary buds 1 to several, bundled. Outer bark brown to whitish brown to whitish, not fissured, not peeling, c. 0.25 mm thick; under bark green; inner bark brown to light red-brown to white inwards, c. 6 mm thick; sapwood cream to straw to pinkish brown to orange-brown to whitish red; heartwood brown.. Leaves: petiole 1–4.1 cm long, diameter 1–2 mm, transversely grooved, (densely) hairy, upper pulvinus 1.5–3.5 mm thick; blade elliptic, 6.8–25.1 by 4.1–10.2 cm, length/width ratio 1.7–2.5, generally drying greenish, base rounded to acute, margin entire, often undulate, apex emarginate to cuspidate, upper and lower surface glabrous to slightly hairy, more densely hairy on venation and especially the midrib, upper surface dark green, lower surface yellow-green to light green, surfaces with 1 or 2 basal extrafloral nectaries, midrib without extrafloral nectaries, rare on lamina, veins 6–9 per side. Staminate inflorescences up to 8.5 cm long; bracts 1.3–1.5 by 0.5–0.7 mm. Staminate flowers c. 9 by 4.8 mm, white to yellow; calyx 3-lobed, lobes basally fused, ovate to elliptic, 2.8–4.2 by 2–2.5 mm, outside densely hairy, inside hairy; filaments 2.1–2.9 by c. 0.2 mm, white; anther 0.7–0.8 by 0.6–0.8 mm, connective rectangular, without apical appendage; disc glands strap-like. Pistillate flowers and fruits unknown, fruits reported to be green-brown.

    Distribution — Malesia: Endemic in New Guinea.

    Habitat & Ecology — In primary lowland rain forest and secondary vegetation. Soil: sandy clay, clay. Altitude: 7–400 m. Flowering: January, May-July, September; fruiting: May.

    Vernacular names — Indonesian Papua: Aiaidia (Wandammen); Mangossosoai (Roberbai, Japen dialect); Tabes, Tepet (Moejoe).

    Note — This species, and the newly described P. esdras, both from New Guinea, are the only species of which the fruits are still unknown. This hampers identification.

5. Ptychopyxis costata Miq.

    Ptychopyxis costata Miq., Fl. Ind. Bat., Suppl. (1861) 402; Hook.f., Hooker’s Icon. Pl. 18 (1887) tab. 1703; Fl. Br. India 5 (1887) 455; Ridl., Fl. Malay Penins. 3 (1924) 295; Croizat, J. Arnold Arbor. 23 (1942) 48; Airy Shaw, Kew Bull. 14 (1960) 366; Whitmore, Tree Fl. Malaya 2 (1973) 127; Airy Shaw, Kew Bull., Addit. Ser. 8 (1980) 198; Kew Bull. 36 (1981) 340; Govaerts et al., World Checkl. Bibliogr. Euphorb. 4 (2000) fig. 1380; Radcl.-Sm., Gen. Euphorb. (2001) 172, Fig. 20a–f; Stoops & Welzen, Nordic J. Bot. 31 (2013) 103, Fig. 7. — Type: Teijsmann HB 1125 (holo U), Sumatra occid., prope Lubu-alang.

Trees; nodes not thickened; axillary buds several, bundled, apically long aristate, apex caudate. Leaves: petiole densely hairy; blade elliptic to narrowly obovate, 10.4–30.7 by 5.3–11.3 cm, base acute, margin entire, recurved; upper surface glabrous except for the densely hairy midrib, lower surface densely hairy all over, without basal or apical extrafloral nectaries, only along the midrib and on the lamina; venation especially basally bullate, on lower surface basal nerves raised high above surface, interveinal region near midrib resembling cavities. Fruits globose, with 6 thickened longitudinal ridges over the septa and locules, between the ridges often lower transverse ridges, 3 locules developed, indumentum consisting of short and long, more or less stinging hairs.

Key to the varieties

 

1a.	Petioles straight; blades elliptic to obovate, 9–14 veins per side	a. var. costata
1b.	Petioles twisted; blades obovate to narrowly obovate, 14–26 veins per side	b. var. oblanceolata

 

a. var. costata

 

    Ptychopyxis costata Miq. var. costata: Airy Shaw, Kew Bull. 14 (1960) 366; Stoops & Welzen, Nordic J. Bot. 31 (2013) 103, Fig. 2 i, j, 7.

 

 

Trees, up to 21 m high, diameter up to 30 cm; buttresses up to 60 cm high, 60 cm out; flowering branches c. 3 mm thick. Leaves: petiole 1.3–5.7 cm long, diameter 1–2 mm, straight, upper pulvinus hardly broader than petiole, 2.2–3 mm diameter; blade elliptic to obovate, 10.4–24.5 by 6.5–11.3 cm, length/width ratio 1.6–2.2,  apex acuminate to cuspidate; lower surface often with many extra floral nectaries along the midrib and less numerous on the lamina, veins 9–14 per side. Staminate inflorescences young. Staminate flowers c. 7.1 by 6.9 mm diam.; calyx 4-lobed, lobes basally fused, triangular, c. 4.1 by 1.9–3.1 mm, recurved, outside and inside densely hairy; filaments 0.8–2.1 by <0.1 mm; anthers 0.7–0.8 by 0.3–0.4 mm, connective triangular, with apical appendage; disc glands strap-like. Pistillate flowers unknown. Young infructescences short, c. 2 cm long; young fruit without obvious longitudinal ridges. Seeds unknown.

    Distribution — Malesia: Sumatra, Borneo.

    Habitat & Ecology — Dipterocarp lowland forest. Soil: sandy. Altitude: 50 m. Fruiting: September.

    Vernacular names — Resak lingeh.

 

b. var. oblanceolata Airy Shaw

 

    Ptychopyxis costata Miq. var. oblanceolata Airy Shaw, Kew Bull. 14 (1960) 366; Whitmore, Tree Fl. Malaya 2 (1973) 127; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 189; Stoops & Welzen, Nordic J. Bot. 31 (2013) 104, Fig. 1d, e, 2b, 7. — Type: Scortechini s.n. (holo K), Malay Peninsula, Perak.

 

   

 

Trees up to 34 m high, diameter  up to 38 cm; without buttresses; flowering branches 2–4.5 mm thick. Outer bark reddish brown, hoop-marked, smooth; inner bark brown; sapwood yellow. Leaves: petiole 0.9–1.8 cm long, diameter 1.8–3.8 mm, twisted, upper pulvinus 2.5–4 mm diameter; blade obovate to narrowly obovate, 20.6–30.7 by 5.3–8.9 cm, length/width ratio 3.4–3.9, apex rounded to cuspidate, upper surface dark green, surfaces with only extrafloral nectaries on the lamina, veins 14–26 per side. Staminate inflorescences several together, up to 7. 5 cm long; bracts 4.2–5.2 by 1–1.8 mm. Staminate flowers: only buds seen, pale green, hairs outside light brown, stamens white. Pistillate inflorescences axillary or cauliflorous, very short, with many empty bracts and bracteoles; bracts c. 5.5 by 0.9 mm. Pistillate flowers unknown. Fruits globose with long beak, diameter 24.5–35.5 mm, beak up to 2 cm long, yellow; wall 0.5–1 mm thick, in between the longitudinal ridges transverse ridges, perhaps as result of drying; columella present or absent; locules 3; stigmas persistent. Seeds unknown.

    Distribution — Malesia: Malay Peninsula, Sumatra and Borneo.

    Habitat & Ecology — Mixed dipterocarp forests and regenerated forests. Altitude: 100–600 m. Flowering: May to June, October; fruiting: June to July, December.

    Uses — Fruit (sarcotesta) edible.

    Vernacular names — Malay Peninsula: Mendaroh. Borneo: Bantas.

 6. Ptychopyxis esdras Stoops

    Ptychopyxis esdras Stoops in Stoops & Welzen, Nordic J. Bot. 31 (2013) 104, Fig. 8. — Ptychopyxis glochidiifolia auct. non Airy Shaw: Airy Shaw, Kew Bull., Addit. Ser. 8 (1980) 198. — Type: Brass 6609 (holotype L; isotype A, n.v.), Papua New Guinea, Fly River.

Trees; nodes not thickened; flowering branches 0.5–0.9 mm thick; axillary buds 2, collateral. Outer bark dark brown, somewhat fibrous. Leaves: petiole 0.4–0.7 cm long, diameter 0.7–1 mm, slightly transversely grooved, upper pulvinus c. 1.1 mm diameter; blade ovate, 2.9–4.4 by 1.5–1.9 cm, length/width ratio 1.9–2.3, base acute to obtuse, margin entire, apex retuse to acuminate, upper and lower surface occasionally covered with hairs, midrib hairy, lower surface with 2 extrafloral nectaries at base, along midrib occasionally, absent between veins, veins 4 or 5 per side. Staminate inflorescences axillary, up to 1.5 cm long; bracts narrow-triangular, 2.1–2.8 by c. 0.7 mm, bracteoles distinct, smaller. Staminate flowers c. 3.7 mm long, diameter c. 3.9 mm, brown; calyx 4-lobed, lobes basally fused, triangular to ovate, 2.2–2.5 by 1.1–3.1 mm, recurved, outside hairy, inside few hairs present; filaments 0.9–1.1 by 0.1–0.2 mm; anthers 0.8–0.9 by 0.6–0.7 mm, connective rectangular, with apical appendage; disc glands strap-like. Pistillate flowers and fruits unknown.

    Distribution — Malesia: Endemic in New Guinea.

    Habitat & Ecology —Altitude: c. 80 m. Flowering: May.

    Notes — 1. This description is based on only one very typical, flowering specimen.

2. See also note under P. chrysantha.

7. Ptychopyxis glochidiifolia Airy Shaw

    Ptychopyxis glochidiifolia Airy Shaw, Kew Bull. 14 (1960) 373; Meijer, Bot. News Bull. Forest Dept. Sabah 7 (1967) 53; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 189; Stoops & Welzen, Nordic J. Bot. 31 (2013) 104, Fig. 1f, 2d, 9. — Type: Kostermans 4521 (holo K; iso L), E. Borneo, Sg. Wain region, N of Balikpapan.

    Ptychopyxis nervosa Airy Shaw, Kew Bull. 20 (1966) 27. — Type: Krukoff 4074 (K holo; iso L), Sumatra, East Coast, Masihi Forest Reserve, Asahan.

Trees, up to 45 m high, diameter up to 55 cm; bole fluted or with buttresses up to 2 m high, out 50 cm; nodes not thickened; flowering branches 0.2–1.2 mm thick; axillary buds 1–3, collateral. Outer bark grey to grey-brown to brown, mottled, c. 0.5 mm thick, smooth to hoop-marked; inner bark pale to light brown, 4–10 mm thick, hard; sapwood honey-yellow to light brown, c. 3 cm thick; heartwood darker, hard, without smell. Leaves scattered to clustered at apex; petiole 1.2–3.8 cm long, diameter 0.5–1.2 mm, transversely grooved, hairy, upper pulvinus 1.5–2 mm diameter; blade mostly ovate to elliptic, 4.5–11.7 by 2.4–4.9 cm, length/width ratio 1.9–2.4, base obtuse to acute, margin entire, apex acuminate to cuspidate, upper and lower surface occasionally hairy, lower surface somewhat denser, extrafloral nectaries on lower surface basally and apically absent, along the midrib and between the veins rare, veins 4–9 per side. Staminate inflorescences paniculate, up to 17 cm long (Sumatra) with lower bracts leaf-like, or axillary racemes, up to 4.5 cm (Borneo); bracts 1.3–1.7 by 0.4–0.5 cm. Staminate flowers in bud or caducous; calyx 3–5-lobed, lobes ovate, broken, outside hairy, inside glabrous; stamens many, filaments white, caducous; disc glands small, bulbous. Pistillate flowers not seen. Young infructescences axillary to ramiflorous, racemes, up to 4 cm long; bracts 2–3.5 by 0.7–0.8 mm. Fruits spheroidal to asymmetrically ovoid, diameter 3.7–14 mm, without appendages, yellow green to rusty or red-brown, indumentum mainly of short hairs with a few long ones; wall 0.3–1.1 mm thick, slightly wrinkled when dry, disc basal, annular, with 3 triangular, densely hairy structures; columella absent; locules 2; stigmas persistent. Seeds unknown.

    Distribution — Malesia: Sumatra and Borneo.

    Habitat & Ecology — Mixed dipterocarp forests, secondary forests, hills and ridges. Altitude: 10–400 m. Soil: sand, loam and clay. Flowering: March, October to November; fruiting: April and September.

    Uses — Firewood.

    Vernacular names — Borneo: Kalimantan: Kaju api (= firewood), Mampam.

8. Ptychopyxis grandis Airy Shaw

    Ptychopyxis grandis Airy Shaw, Kew Bull. 14 (1960) 367; Kew Bull., Addit. Ser. 4 (1975) 190; Stoops & Welzen, Nordic J. Bot. 31 (2013) 106, Fig. 1c, 2g, 10. —Type: Jacobs 5218 (holo K; iso L), Sarawak, 3^rd Division, Kapit dist., Belaga subdist., left bank of Rajang River, c. 10 km below Belaga, Segaham range, near Belaga airfield.

Trees, up to 18 m high, diameter 8 cm; nodes not thickened to thickened; flowering branches 1.2–7.5 mm thick; axillary buds 1 or 2, collateral. Outer bark grey to (dark) brown, 0.2–1 mm thick, lenticellate, smooth to fissured to scaly; inner bark white; wood white. Leaves crowded at top of the twigs: petiole cylindrical to flattened, 0.8–8.9 cm long, diameter 2–6 mm, transversely grooved, hairy, epidermis loose and papery when dry, upper pulvinus 6–7 mm diameter; blade elliptic to narrowly elliptic to narrowly obovate, 24.7–59.7 by 5.4–25.4 cm, length/width ratio 2.4–4.6, base emarginate to acute, margin entire, regularly slightly undulate, especially basally recurved, apex rounded to cuspidate, upper and lower surface usually glabrous except for the midrib, extrafloral nectaries very obvious, visible to the naked eye, 1–4 basally, 2 to several at apex, along midrib rarely to occasionally to frequently, between veins none to frequently, upper surface darker green than lower surface, veins 9–19 per side. Staminate inflorescences racemes, axillary, up to 5 cm long; bracts c. 4 mm long. Staminate flowers diameter 4.1–5.5 mm, red; calyx 3–5-lobed, lobes triangular to ovate, 2.1–3.9 by 2.5–3.2 mm, recurved, outside hairy, inside glabrous or with a few hairs; filaments 0.6–1.2 by 0.1–0.2 mm; anthers 0.4–0.5 by 0.3–0.6 mm, connective rectangular, without apical appendage; disc glands small, bulbous. Pistillate inflorescences racemes, occasionally cauliflorous, up to 5 cm long; bracts 4–5.2 by 1.3–1.6 mm. Pistillate flowers unknown; young fruits with green to purplish calyx; ovary purple; stigma yellow-green.. Fruits ellipsoid with beak, diameter 1.6–28.5 mm, beak up to c. 15 mm long, purple to red to brown; wall 0.5–2.5 mm thick, 3-ribbed to warty; columella absent; locules 2 or 3; stigmas persistent. Seeds long-ovoid, diameter 15.0–17.1 mm.

    Distribution — Malesia: Endemic in Borneo.

    Habitat & Ecology — Mixed dipterocarp forests and logged areas, often along streams. Soil: sandstone, sandy loam and red and yellow clay. Altitude: 10–1000 m. Flowering: August; fruiting: January, March, August, October, December.

    Uses — Fruit edible.

    Vernacular names — Brunei: Bantas (Iban). Kalimantan: Serantong; Songa. Sarawak: Bedulang, Bertulang, Buah berdulang, Pangkal bedulang; Buah bidulang (Iban).

9. Ptychopyxis javanica (J.J.Sm.) Croizat

    Ptychopyxis javanica (J.J.Sm.) Croizat, J. Arnold Arbor. 23 (1942) 49; Airy Shaw, Kew Bull. 14 (1960) 371; Kew Bull. 16 (1963) 348; Backer & Bakh.f., Fl. Java 1 (1963) 479; Airy Shaw, Kew Bull. 26 (1972a) 327; Whitmore, Tree Fl. Malaya 2 (1973) 127; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 190; Kew Bull. 36 (1981) 341 (as cf.!); Welzen & Chayam., Fl. Thailand 8 (2007) 512, Fig. 67c–g; Stoops & Welzen, Nordic J. Bot. 31 (2013) 107, Fig. 11c–g, 12. — Podadenia javanica J.J.Sm. in Koord. & Valeton, Meded. Dep. Landb. 10 (1910) 388; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii (1914) 21. — Lectotype (Stoops & Welzen 2012): Koorders 12234 (lecto L), Indonesia, Java, Preanger prov.

    Ptychopyxis angustifolia Gage, Rec. Bot. Surv. India 9 (1922) 248; Ridl., Fl. Malay Penins. 3 (1924) 296; Croizat, J. Arnold Arbor. 23 (1942) 48. — Syntypes: Curtis 3567 (K), Malaysia, Penang, Waterfall Gardens; Haniff 15637 (K), Malaysia, Kedah, Gunong Rya; King’s collector 7678 (K), Malaysia, Perak, Larut; Ridley (K), Malaysia, Penang, Waterfall Gardens.

    Ptychopyxis arborea (Merr.) Airy Shaw var. cacuminum Airy Shaw, Kew Bull. 20 (1966) 28; Kew Bull., Addit. Ser. 4 (1975) 188. — Type: Endert 3931 (holo L), Indonesia, W. Koetai, no. 39, near Mt.Kemoel.

Trees to treelets, up to 24 m high, diameter up to 40 cm; nodes thickened or not; buttresses small; flowering branches 0.4–1.5 mm thick; axillary buds 1 or 2, collateral. Outer bark grey to pale brown and green, lenticellate to flaking green; inner bark white to light yellow to brown; sapwood white to yellow, with thin rays. Leaves: petiole 1.6–7.5 cm long, diameter 1–1.8 mm, transversely grooved, hairy, upper pulvinus 2.3–2.5 mm diameter; blade (narrowly) elliptic to obovate, 8.8–23.3 by 3.2–8.6 cm, length/width ratio 2.7–2.8, drying brownish, base obtuse to acute, margin entire, apex emarginate to cuspidate, upper and lower surface glabrous except for often hairs on venation, lower surface with 0–2 extrafloral nectaries at base, along midrib none to occasionally, between veins rarely to occasionally, apically absent, veins 7–13 per side. Staminate inflorescences paniculate racemes, axillary to ramiflorous, up to 12 cm long; bracts 1.3–1.6 by c. 0.7 mm. Staminate flowers 3.2–5.2 mm long, diameter 5.1–5.9 mm, yellowish green to yellow; calyx 3-lobed, lobes basally fused, triangular to ovate, 2.9–3.1 by 2.1–2.6 mm, recurved, outside and inside densely hairy; filaments 1–2.3 by 0.1–0.2 mm; anthers 0.6–0.9 by 0.3–0.5 mm, connective triangular to rectangular, with apical appendage; disc glands strap-like to triangular to round. Pistillate flowers diameter c. 5 mm; bracts c. 1.5 by 0.6 mm; calyx 5-lobed, c. 2 mm long, lobes basally fused, (narrowly) triangular, 2.4–2.8 by 0.9–1.5 mm, outside and inside densely hairy; disc without appendages; ovary globose, c. 2.1 by 2.9 mm; locules 2 or 3; style triangular, c. 0.4 mm long; stigmas c. 1.5 mm long, recurving, above papillose to velutinous, underneath velutinous. Fruits ovoid, asymmetrical, diameter 17–20.5 mm, green, hairy, without appendages, indumentum of only short hairs, apex rounded; wall 0.9–1.9 mm thick; columella absent; stigmas 2 or 3, persistent. Seeds ovoid but flattened on one side, diameter 9.5–14.8 mm; sarcotesta white.

    Distribution — Thailand, Vietnam, Malesia: Malay Peninsula, Sumatra, Java, Borneo.

    Ptychopyxis javanica (dot) and P. plagiocarpa Airy Shaw (star).

    Habitat & Ecology — Wet evergreen and secondary forests. Soil: sand. Altitude: 25–1600 m. Flowering: March to May, July, September to October; fruiting: April. Fruits eaten by monkeys (J.J.Smith 1910).

    Uses  — The wood is strong and suitable for house construction (J.J.Smith 1910).

    Vernacular names — Malay Peninsula: Napoh. Java: Ramboetan monjet (Sundanese; J.J.Smith 2010)

    Note — See note under P. bacciformis.

10. Ptychopyxis kingii Ridl.

    Ptychopyxis kingii Ridl., Fl. Malay Penins. 3 (1924) 296; Airy Shaw, Kew Bull. 14 (1960) 368; Meijer, Bot. News Bull. Forest Dept. Sabah 7 (1967) 53; Airy Shaw, Kew Bull. 27 (1972b) 86; Whitmore, Tree Fl. Malaya 2 (1973) 127; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 190; Kew Bull. 36 (1981) 341; Radcl.-Sm., Gen. Euphorb. (2001) 172, Fig. 20g, h; Stoops & Welzen, Nordic J. Bot. 31 (2013) 109, Fig. 13. —  Type: King’s collector (Kunstler) s.n. (holo K), Malaya, Perak, Larut.

    Mallotus arboreus Merr. var. platyphyllus Merr., Pap. Michigan Acad. Sci. 19 (1933) 161. — Type: Yates 2638 (UC; iso L), Sumatra, East Coast, Masihi, Asahan.

Trees, up to 40 m high, diameter up to 65 cm; bole straight; branches almost horizontal; nodes not thickened to thickened; flowering branches 1.1–4.7 mm thick; axillary buds 1–3 to several, collateral, bracts not aristate. Indumentum red-brown to brown. Outer bark grey to grey-brown to brown, sometimes slightly hoop-marked, smooth to slightly scaly to deeply fissured; inner bark yellowish to orange-red to brownish with blackish streaks; sapwood white to pink to pale ochre. Leaves: petiole 1.5–4.2 cm long, diameter (1–)1.9–3.1 mm, transversely grooved, densely hairy with mainly short, usually dark brown (sometimes yellowish) papilla-like hairs (c. 0.1 mm long), few long yellowish hairs (c. 0.3 mm long), glabrescent, upper pulvinus (2–)3–6 mm diameter; blade elliptic to obovate, 10.2–37.5 by 5.5–15 cm, length/width ratio 1.9–2.6, drying brown, base obtuse to acute, margin entire, partly revolute, apex emarginate to acuminate, upper surface occasionally hairy, mid-dark green above, midrib usually hairy and brown, lower surface paler green than upper surface, dull, veins usually brownish hairy, especially the midrib, extrafloral nectaries on both surfaces basally 0–4, along midrib occasional to frequent, on lamina rare, apically absent, veins 7–14 per side. Staminate inflorescences several together, up to 10.3 cm long; bracts 1-3 by c. 1 mm. Staminate flowers c. 7 by 5 mm, brownish hairy; calyx 3–5-lobed, lobes basally fused, triangular to ovate, 2.3–4 by 5–5.2 mm, recurved, outside densely hairy, inside with few hairs; filaments c. 3.8 by 0.1 mm, white; anthers c. 1 by 0.5 mm, connective broadly triangular to rectangular, with appendage at apex; disc glands strap-like, densely hairy. Pistillate inflorescences and flowers unknown. Young inflorescences up to 6 cm long; style present, in young fruit c. 2.5 mm long; bracts 1.7–2.3 by 1–1.2 mm. Fruits subglobose usually with a small beak (remnant of style), not lobed, 3.2–5 cm wide by 3.2–6.1 cm high, green to yellow to dull yellowish brown-green to orangish brown, without appendages, indumentum of short and fewer long hairs; stigmas deciduous; disc without triangular appendages; wall 0.5–6.1 mm thick, outside wrinkled to warted to ribbed when dry; columella present or not present; persistent stigmas absent; locules 3 or 4. Seeds ovoid, diameter 12.1–19.1 mm; sarcotesta fleshy, pale yellowish green; wall layered, outer layer hard, blackish, second layer rather fleshy, brownish, inner layer more or less gelatinous.

    Distribution — Malay Peninsula, Sumatra and Borneo.

    Habitat & Ecology — Primary lowland dipterocarp forest and disturbed forests and primary lowland forests, on hillsides and along small streams on well-drained clay alluvium. Altitude: 10–600 m. Flowering: February, March, May to August, November; fruiting: whole year through in various stages of development.

    Uses — Fruits eaten in Borneo (edible part not indicated, probably seed or layer around seed).

    Vernacular names — Borneo: Kalimantan: Kaju palih; Sabah: Gapas gapas; Sarawak: Panyai (Berawan); Ukut (Iban).

    Note — See note 2 under P. arborea.

Excluded species

Ptychopyxis thwaitesii (Müll.Arg./Baill.) Croizat, J. Arnold Arbor. 23 (1942) 48. = Podadenia sapida Thwaites