Dissochaeta fallax (Jack) Blume, Flora 14: 493. 1831.

Kartonegoro, Abdulrokhman, Veldkamp, Jan Frits, Hovenkamp, Peter & Welzen, Peter van, 2018, A revision of Dissochaeta (Melastomataceae, Dissochaeteae), PhytoKeys 107, pp. 1-178 : 1

18. Dissochaeta fallax (Jack) Blume, Flora 14: 493. 1831. Fig. 13 , Map 12

Melastoma fallax Jack, Trans. Linn. Soc. London 14: 13. 1823.

Melastoma reinwardtianum Blume, Bijdr. Fl. Ned. Ind. 17: 1069. 1826. Type: Indonesia. West Java, H. Kuhl & J.C. van Hasselt s.n. (lectotype, designated by Bakhuizen van den Brink f. 1943, pg. 119: L [L0537272]!; isolectotypes L [L0537269, L0537270]!).

Melastoma leprosum Blume, Bijdr. Fl. Ned. Ind 17: 1068. 1826. p.p., excl. type

Dissochaeta reticulata Blume, Flora 14: 499. 1831. Type: Indonesia. Java, C.L. Blume s.n. (lectotype, designated by Bakhuizen van den Brink f. 1943, pg. 144: L [L0008896]!; isolectotypes: L [L0008897]!, P [P05283565]!).

Dissochaeta ligulata Blume, Mus. Bot. 1(3): 35. 1849. Type: Indonesia. Java, F.W. Junghuhn s.n. (lectotype, designated by Bakhuizen van den Brink f. 1943, pg. 144: L [L0008898]!).

Omphalopus fallax (Jack) Naudin, Ann. Sci. Nat., Bot. sér. 3, 15: 277, pl. 4, fig. 5. 1851.

Omphalopus reticulatus (Blume) Naudin, Ann. Sci. Nat., Bot. sér. 3, 15: 278. 1851.

Dissochaeta diepenhorstii Miq., Fl. Ned. Ind., Eerste Bijv. 2: 317. 1861. Type: Indonesia. West Sumatra: Priaman, H. Diepenhorst HB 1323 (lectotype, designated by Bakhuizen van den Brink f. 1943, pg. 119: U [0004007]!; isolectotype: BO [BO1865969]!).

Anplectrum ligulatum (Blume) Triana, Trans. Linn. Soc. London 28: 85. 1872.

Dissochaeta inappendiculata auct. non Blume: Triana, Trans. Linn. Soc. London 28: 84. 1872. p.p., excl. type.

Diplectria ligulata (Blume) Kuntze, Revis. Gen. Pl. 1: 246. 1891.

Dissochaeta celebica auct. non. Blume: Baker f., J. Bot. 62 (Suppl.): 40. 1924. p.p., excl. type.

Dissochaeta leprosa auct. non. Blume: Baker f., J. Bot. 62 (Suppl.): 40. 1924. p.p., excl. type.

Dissochaeta reinwardtiana (Blume) Hochr., Candollea 2: 472. 1925.

Omphalopus fallax (Jack) Naudin var. novoguineensis Mansf., Bot. Jahrb. Syst. 60: 113. 1925. Type: Papua New Guinea. Kaiser Wilhelmsland, Kani-Gebirges, 1000 m, 7 Jan 1908, R.F.F. Schlechter 15159 (lectotype, designated here: NY [NY00229576, image seen]!).

Neodissochaeta reticulata (Blume) Bakh. f., Contr. Melastom.: 143. 1943.

Dissochaeta velutina Blume var. reticulata (Blume) J.F.Maxwell, Gard. Bull. Singapore 33: 321. 1980.

Type.

Indonesia. Sumatra, Jack s.n. (lost); Indonesia. Bengkulu: Ajer Angat, G. Kaba, H.O. Forbes 2882a (neotype, designated by Kartonegoro and Veldkamp 2010, pg. 132: L [L0822678]!; isoneotype: BM!).

Description.

Climbing up to 25 m in height. Branchlets terete or subquadrangular, 3-6 mm in diameter, puberulous to brown stellate-furfuraceous; nodes swollen, with raised interpetiolar ridge; internodes 3.5-7 cm long. Leaves: petioles terete, 8-20 mm long, puberulous to densely stellate-furfuraceous; blades ovate to ovate-oblong, 6-15.5 × 3-7 cm, membranous, base cordate or subcordate, rarely rounded, margin entire, apex acuminate, tip 0.5-1 cm long; nervation with 1 pair of lateral nerves and 1 pair of intramarginal nerves; adaxially glabrous, light green, glossy, abaxially densely brown stellate-furfuraceous. Inflorescences terminal and in the upper leaf axils, up to 35 cm long, many-flowered; main axis densely stellate-furfuraceous; peduncle up to 8 cm long; primary axes up to 15 cm long with 4 or 5 nodes, secondary axes 3-3.5 cm long with 1-3 nodes, tertiary axes up to 5 mm long with 1 node or undeveloped; bracts linear, 2-3 mm long, densely brown furfuraceous, caducous; bracteoles linear, minute, ca. 1.5 mm long, brown furfuraceous, caducous; pedicels densely stellate-furfuraceous, 3-5 mm long in central flowers, 1-2 mm long in lateral flowers. Hypanthium urceolate, 3-6 × 2-3 mm, green, densely stellate-furfuraceous; calyx lobes truncate with triangular tips, 0.5 –1(– 2.5) mm long, widened, glabrous or with stellate hairs; petals bud rounded or rarely subconical, 4-10 mm long, with a rounded tip; mature petals obovate, 7-8 × 2-4 mm, not reflexed, base clawed, apex rounded, glabrous or inside with appressed hairs at the base, white pinkish or pink. Stamens 4 or 8, equal or subequal when 8, all fertile, filaments bright white, straight, curved at the end; alternipetalous stamens with 4-5 mm long filaments, anthers ovate or lanceolate, when mature falcate, straight, medifixed, thecae 3-6.5 mm long, bright yellow, beaked, pedoconnective not developed, basal crests triangular, orbicular or ligular, 1-3 mm long, attached to the attachment of the filament, white, lateral appendages absent; the oppositipetalous stamens smaller, with 2-3 mm long filaments, anthers oblong, oblong-lanceolate, medifixed, thecae 2-4 mm long, tessellate-reticulate, yellow, basal crests ligular, erect or sometimes tapering horizontally inward to the anther, 1-1.5 mm long, lateral appendages absent. Ovary half or ⅔ of hypanthium in length, apex pubescent; style 7-15 mm long, curved at the end, glabrous, white with pinkish base; stigma minute; extra-ovarial chambers absent or shallow. Fruits urceolate or subglobose, 4 –8(– 12) × 4 –5(– 7) mm, stellate-puberulous, calyx lobe remnants persistent, 1-2 mm long. Seeds ca. 0.5 mm long.

Distribution.

Thailand (Southern Peninsula), Peninsular Malaysia, Sumatra, Java, Lesser Sunda Islands (Bali, Lombok) and New Guinea (Papua New Guinea).

Ecology and habitat.

Primary or secondary submontane forest, rarely near a crater or at the edge of a forest, 400-1600 m elevation.

Vernacular names.

Sumatra: air wangian (Minang); akar gameh (Pariaman); gedang serian (Lampung). Java: harendong areuy, harendong beureum, harendong oyot (Sunda). Lesser Sunda: priyato (Bali).

Notes.

1. Dissochaeta fallax is easily distinguished by its 4 or 8 stamens with tessellate-reticulate thecae and medifixed anthers. The hypanthium is suburceolate, slender and smaller than the petals in bud, which are usually rounded. This species is common in West Malesia (Sumatra and Java), but so far not found in Borneo and further east except for one collection from New Guinea. The stamens make Dissochaeta fallax so different from the other species that it has long been regarded as a distinct genus, Omphalopus ( Naudin 1851, Miquel 1855, Triana 1872, Cogniaux 1891, Bakhuizen van den Brink f. 1943). We regard these differences only as infrageneric variation and we follow previous authors (Blume 1831, Maxwell 1980b, Clausing and Renner 2001, Kartonegoro and Veldkamp 2010) to include it in Dissochaeta . Future phylogenetic analyses may point out the true relationship of this species.

2. The correct identification of D. reticulata is problematic. Naudin (1851) and Miquel (1855) correctly considered this species to be part of former Omphalopus , together with O. fallax based on its stamen characters. Blume (1831), Veldkamp (1979), Kartonegoro and Veldkamp (2010) regarded it as a distinct species in Dissochaeta based on 8 subequal fertile stamens, in which it is similar to D. inappendiculata . Bakhuizen van den Brink f. (1943, 1964) placed this species under Neodissochaeta . On the other hand, Maxwell (1980b) erroneously considered the species to be a variety of D. velutina (a synonym of D. vacillans ). Like D. fallax , the type of D. reticulata also shows the stamens to have tessellate-reticulate thecae, medifixed stamens and an inappendiculate crest. Therefore, the name is here synonymised with D. fallax , whereby the variation in the number of stamens became 4 or 8.

Selected specimens examined.

THAILAND. Nakhon Si Thammarat: Khao Luang, 750 m, 19 May 1968, C.F. van Beusekom & C. Phengkhlai 880 (K, L, P). MALAYSIA. Selangor: Genting Highlands, Gunong Ulu Kali, 1500 m, 9 Apr 1978, J.F. Maxwell 78-81 (L). INDONESIA. Aceh: Gayoland, between Kampong Kapi and Kampong Aunan, 1100 m, 21 Mar 1937, C.G.G.J. van Steenis 9972 (BO). Bengkulu: Air Hangat, Bukit Kaba, H.O. Forbes 2882a (BM, L); Suban Ayam, 1200 m, 12 Jul 1916, Ajoeb 350 (BO); Balai, 500 m, 13 Jan 1931, C.N.A. de Voogd 581 (BO, L). Jambi: Kerinci, Siolak Deras, 915 m, 18 Mar 1914, H.C. Robinson & C. Boden-Kloss s.n. (BM, K). Lampung: Sukaraja, 28 Aug 1915, P.J.S. Cramer 107 (BO); Mt. Tanggamus, 1600 m, 2 May 1968, M. Jacobs 8213 (L). North Sumatra: Bandar Baru, Mt. Sibayak, 900 m, 9 Oct 1928, J.A. Lörzing 14075 (BO, L); Sibolangit, 12 Sep 1920, J.A. Lörzing 7351a (BO); Padang Sidempuan, Mt. Lubuk Raya, 1000 m, 13 Apr 1978, Maskuri 282 (BO, L). South Sumatra: Muara Dua, Tenang, 700 m, 10 Jan 1930, C.N.A. de Voogd 556 (BO). West Sumatra: Pariaman, H. Diepenhorst HB 1323 (BO, U); Mt. Malintang, 1 Aug 1918, H.A.B. Bünnemeijer 4225 (BO, K, L, U); Mt. Merapi, 1250 m, 13 Sep 1918, H.A.B. Bünnemeijer 4514 (BO, K, L, U); Lubuk Sikaping, Mt. Gadang, 700 m, 15 Jun 1953, J. van Borssum-Waalkes 1893 (BO, L); Lima Puluh Kota, Kelok Sembilan, 700 m, 20 Dec 1987, M. Hotta & H. Okada 1637 (BO); Ibid., Mt. Sago, Ladang Laweh, 900 m, 28 Jul 1957, W. Meijer 7245 (L); Solok, Mount Talang, 1250 m, 2 Oct 1988, M. Hotta & H. Nagamasu 12 (BO, L). Banten: Between Bayah & Sangkop, 600 m, 20 Jun 1911, C.A. Backer 1722 (BO); Pasir Orai, H.O. Forbes 460 (BM, BO); Mt. Karang, Galusur, 700 m, 31 Jun 1912, S.H. Koorders 40738β (BO). Central Java: Purbalingga, Mt. Slamet, 1300 m, 13 Mar 2004, W.S. Hoover et al. Deden-36 (BO). East Java: Lumajang, Sumber Mujur, Mar 1928, Adm. Ondern. Soember Moedjoer s.n. (BO, L, U). West Java: Mt. Paniisan, 600 m, 28 Oct 1928, C.G.G.J. van Steenis 2300 (BO, L); Leuwiliang, Cianten, 900 m, 30 Aug 1918, C.A. Backer 25698 (BO); Mt. Menapa, 600 m, 18 Dec 1940, C.G.G.J. van Steenis 17373 (BO, K, L); Mt. Salak, Kampong Babojong, 700 m, 18 Sep 1896, S.H. Koorders 24270β (BO, K, L); Mt. Halimun, Malasari, 1055 m, 10 Oct 2017, A. Kartonegoro 1106 (BO, L); Cianjur, Cibeber, Cidadap, 1000 m, R.C. Bakhuizen van den Brink 2769 (BO); Ibid., Takokak, S.H. Koorders 33358β (BO); Tasikmalaya, Singaparna, Mt. Galunggung, 900 m, 13 Aug 1913, C.A. Backer 8619 (BO). Bali: Jembrana, Mt. Mesehe, 500 m, 18 May 2013, A. Kartonegoro et al. 737 (BO); Mt. Pala 495 m, 5 Sep 1918, Sarip 219 (BO, L). West Nusa Tenggara: Lombok, Mt. Rinjani, Jeruk Manis waterfall, 904 m, 16 Feb 2005, H. Azuma et al. A259 (BO). PAPUA NEW GUINEA. Sepik: Kaiser Wilhelmsland, Kani Mountains, 1000 m, 7 Jan 1908, R.F.F. Schlechter 15159 (NY).

Figures

Map 12. Distribution of D. fallax (●).

Figure 13. Dissochaeta fallax. a habit b branchlet c hypanthium d Flower e immature fruits. Photographs by A. Kartonegoro; vouchers: Kartonegoro 1106 (BO, L).