Blastus borneensis (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Blastus borneensis Cogn.

Protologue: A.DC. & C.DC., Monogr. phan. 7: 477 (1891).

Family: Melastomataceae

Chromosome number: 2n= unknown

• Blastus cogniauxii Stapf (1894).

• Malaysia: sendudok rimba, kedudok hutan, kedudok cherang (Peninsular).

B. borneensis is distributed in Indo-China (Cambodia, Laos and Vietnam), China (Hainan), peninsular Thailand, Peninsular Malaysia, Sumatra, Borneo and Sulawesi.

It has been reported that a decoction of the roots is drunk in Peninsular Malaysia during the first three days after childbirth as a restorative.

• A branched shrub up to 4.5(-7) m tall; branchlets densely covered with peltate glands.
• Leaves decussately opposite, those of a pair often unequal in size, simple and entire, ovate to elliptical, 3-19(-28) cm × 1-6(-10) cm, attenuate to rounded at base, long-acuminate at apex, with 3(-5) longitudinal veins, with peltate glands below; petiole 0.5-3 cm long; stipules absent.
• Inflorescence an axillary or terminal thyrse rarely more than 5 cm long.
• Flowers regular, bisexual, 4-merous; hypantium campanulate to urceolate, with yellowish peltate glands; sepals very shortly connate into a low rim, up to 0.5(-1) mm long, persistent; petals free, up to 2.5 mm long, white to yellowish or rarely pinkish; stamens inserted on the sepals, up to 6 mm long, filaments and anthers about equal in length; ovary inferior, 4-celled, apically densely covered with peltate glands and deeply depressed, style up to 7(-11) mm long.
• Fruit a loculicidal capsule included in the hypantium, urceolate or cup-shaped, up to 3 mm long, pale brown, many-seeded.
• Seeds cuneate, 0.3-0.4 mm long, with a short beak at chalaza, pale brown, testa bullate.

B. borneensis can be found flowering throughout the year. It is a variable species in which 4 varieties have been distinguished: one in Indo-China, one in Thailand, one (var. pulverulentus (Ridley) C. Hansen) in Peninsular Malaysia and Sumatra, and one (var. borneensis) throughout the area of distribution of the species.

Blastus comprises 12 species and is confined to tropical and subtropical Asia. Southern China is richest in species (9), followed by Indo-China (4). In Malesia, only a single species is found. Blastus is classified in the tribe Oxysporeae, and is related to e.g. Allomorphia and Oxyspora. It is easily recognized by having only 4 stamens and peltate glands.

B. borneensis occurs in primary and secondary rain forest, often dipterocarp forest, from sea-level up to 2100 m altitude.

B. borneensis is widely distributed in the undergrowth of primary as well as secondary forest and does not seem to be easily liable to genetic erosion. However, several other Blastus species seem to be narrow endemics, particularly in southern China and northern Vietnam, whereas some varieties of B. borneensis also have a restricted geographical distribution; these may easily become endangered.

The information available on B. borneensis is restricted to botanical information and a single record on a medicinal use. This is insufficient to allow the prediction of the prospects as a medicinal plant.

• [313]Hansen, C., 1982. A revision of Blastus Lour. (Melastomataceae). Bulletin du Muséum National d'Histoire Naturelle, 4e série, 4, section B, Adansonia, No 1—2: 43—77.

• [121]Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co- operatives, Kuala Lumpur, Malaysia. Vol. 1 (A—H) pp. 1—1240, Vol. 2 (I— Z) pp. 1241—2444.

• R.H.M.J. Lemmens