Melastoma molle Wall. ex Cogniaux (1891: 346)

Neo, Louise, Tan, Hugh T. W. & Wong, K. M., 2020, Studies in Southeast Asian Melastoma (Melastomataceae), 4. Clarification of Melastoma crinitum in Southeast Asia and the reinstatement of Melastoma molle, Phytotaxa 436 (2), pp. 196-200 : 197-199

Melastoma molle Wall. ex Cogniaux (1891: 346)

= Melastoma molle Wallich (1831: 143) nom. inval.

Type: — SINGAPORE. 1822, Wallich 4046 (lectotype K [ K000867837 ] designated here, isolectotypes K [ K000867836 ; K001038027 ]) .

Shrub or treelet. Twigs slightly flattened in the younger parts and terete in the older parts, covered with erect, strongly incurved to ascending scales, very dense on the younger parts and obscuring the twig surface, sparser on the older parts with the twig surface visible between the scales, the scales terete or narrowly lanceolate with entire margins, and 2–4 mm long (but up to 10 mm long at the twig nodes). Leaves with petioles 1–3 cm long, 1–2 mm wide, covered with ascending, terete or narrowly lanceolate scales (up to 3 mm long); blades elliptic, 7–21.5 cm long, 4–8.5 cm wide; longitudinal veins 4 in addition to the midrib, the outermost ones (2–) 3–5 mm away from the margins (sometimes with an additional pair of veins <1 mm away from the margins), sunken above, prominently raised below and covered with terete to narrowly lanceolate scales (up to 3 mm long); upper blade surface scabrid, with spicule-like crystalliferous cells ca. 0.5 mm long in the lamina, branched at the base and distally emergent as terete hairs of 1–1.5 mm long (best examined in dried material using a stereozoom microscope); lower blade surface with emergent terete hairs of 0.5–1 mm long on the lamina and ca. 3 mm long on the lateral veins. Flowers 3‒5 in tightly-bunched cymes (inflorescence axes typically hidden by the flowers); pedicels 3–6 mm long; bracteoles lanceolate, 6–15 mm long, 2–5 mm wide; hypanthium sub-globular, ca. 8–11 mm long, ca. 8 mm wide, densely covered with overlapping, ascending to spreading terete bristles with entire margins and of up to 5–8 mm long; hypanthium lobes 4–7 mm long, covered with scales of the same type as on the hypanthia; petals ca. 12 mm long; stamens anisomorphic, the 5 long stamens with anthers ca. 7–8 mm long, filaments ca. 8 mm long, these joined by connectives ca. 6–7 mm long and bearing a 2-lobed spur, the 5 short stamens with anthers ca. 7 mm long, filaments ca. 8 mm long, the connectives inconspicuous and bearing a 2-lobed spur; style not seen. Fruits globular, 9–11 mm long, 9–11 mm wide when mature, covered with scales of the same type as on the hypanthia, said to be reddish in fresh material; seeds not seen, but ‘ripe seeds are red’ (notes in Corner s.n.).

Distribution: —According to Ridley (1922), this species occurs in “dense forest” (probably referring to forest that is not easily accessed, rather than forest with a closed canopy) and is “extremely rare”. It is restricted to southern Peninsular Malaysia ( Fig. 2 ) in the lowlands and foothills of the Main Range, and is apparently extinct from its type location, Singapore, where it has not been recorded for more than a hundred years. Although Melastoma molle has also been said to occur in Sumatra ( Ridley 1922), we have not found any specimens from Sumatra that might represent this species in BO and K.

Additional specimens examined: — MALAYSIA. Johore: October 1929, Teruya 1145 ( KEP [175876], SING [0240940]) ; Batu Pahat, Kampong Simpai , 3 November 1892, Kelsall s.n. ( SING [0240933]) ; Bekok, Labis Forest Reserve, 30 m, 31 May 1970, Mohd. Shah & Samsuri MS.1714 ( KLU [13108], SING [0240935]), headwaters of Sungei Segamat due south of G. Pukin , 1400 ft, 15 March 1970, Everett FRI 14056 ( KEP [67628]) ; Kluang, Lenggor Forest Reserve , 200 ft, 7 April 1965, Ng KEP 99071 ( KEP [175899]), NW Gunung Blumut, 15 May 1968, Whitmore FRI 8759 ( KEP [67625], SING [0240942]) ; Gunung Panti, 610 m, December 1892, Ridley s.n. ( SING [0240936]), Sungei Segun, near Gunung Panti, Mawai end, low elevation, 12 May 1935, Corner s.n. ( SING [0240931]) ; Gunung Pulai, north side, 152 m, 22 January 1961, Burkill HMB.2573 ( SING [0240930]), Sungei Ayer Hitam Kechil , 17 June 1953, Sinclair 39679 ( SING [0240938]) ; Ulu Endau via Kluang, 213 m, 22 July 1973, Samsuri SA 831 ( SING [0240937]), Endau-Rompin S. P., trail to Bertedung camp from Lubuk Merekek, 2°26.50’N, 103°16.10’E, 337 m, 3 July 2012, Hisham et al. FRI 73805 ( K, KEP [217017], SAN), logging track up Sungei Jasin, 16 May 1985, Kiew RK 1735 ( KEP [175877]) ; Ulu Kahang, 177 m, 3 June 1923, Holttum 10967 ( SING [0240932]). Negeri Sembilan: Gunung Angsi, 18 November 1929, Symington 21361 ( SING [0240939]). Pahang: Gunung Lesong, 6 June 1929, Mahamud 14962 ( SING [0240934]), Lesong Forest Reserve , near Sungei Jekatih, 27 April 1971, Whitmore FRI 15997 ( KEP [67626], SING [0240943]), 13 June 1979, Kamarudin FRI 28382 ( KEP [67627]) ; South East Pahang Aur Forest Reserve Compartment 34, 11 May 1967, Whitmore FRI 3642 ( KEP [175902], SING [0240941]) .

Furthermore, the name Melastoma crinitum Naudin is illegitimate according to Article 53 of the International Code of Nomenclature for Algae, Fungi, and Plants (Shenzhen Code) ( Turland et al. 2018) because it is a later homonym of a Caribbean taxon described by Vahl (1807). Based on our revised circumscription of Melastoma crinitum Naudin , we consider it to be the same as Melastoma penicillatum Naudin (1850: 280) and Melastoma setosum Elmer (1915: 2758) . Melastoma penicillatum Naudin being the earlier name should therefore be used as the correct name for this taxon, which is apparently restricted to the Philippines.

We also note that the name Melastoma penicillatum Naudin has been wrongly applied to a taxon endemic to Hainan, China ( Chen 1984, Chao et al. 2014, Zhou et al. 2017). However, based on our examination of a sample of specimens from the Chinese Virtual Herbarium (http://www.cvh.ac.cn/en), we note differences between this and the Philippine taxon. The longer pedicels and denser covering of reddish-brown bristles on the twigs and petioles of the Chinese taxon (compared to the shorter pedicels and sparser twig and petiole bristles which dry golden brown or black in the Philippine species) suggest that it is not the same species as Melastoma penicillatum from the Philippines. This taxon should also not be Melastoma sanguineum Sims (1821: 2241) , as was suggested by previous opinion ( Chen & Renner 2007), because Zhou et al. (2017) have already demonstrated through molecular evidence that these are two distinct species.

Figures

FIGURE 2. Distribution of Melastoma molle (●) in southern Peninsular Malaysia and Singapore. The inset map depicts Peninsular Malaysia and Singapore.