DURIO MACRANTHA
SCIENTIFIC NAME: Durio macrantha
FAMILY: Bombacaceae
ABSTRACT
An interesting species of Durio from North Sumatra is described and illustrated from a living specimen growing in Bogor.
In 1981 I received from Mr. H. Rijksen a young durian plant, which he had collected in the Mt. Leuser National Park in North Sumatra. Now 10 years later the plant has grown to a tree of 10 m high in my private garden in Gadok near Bogor, and in July 1991 it started to come in bloom. The flower bunches appeared on the bare branches; it took 4-6 weeks from the initial bud to the mature flower. The tree flowered profusely and within three months new buds appeared continuously. It proved to be an undescribed species of durian.
DURIO MACRANTHA Kosterm., species nova
Tree 10 m tall, dbh. 20 cm. Bark smooth, grey. Crown pyramidal, lowest branch 1m above the forest floor, somewhat drooping. Leaves alternate in one plane, chartaceous, lower side concave, oblong, 5-7.5 x 16-22 cm, gradually acuminate or sub-acuminate, base rounded, above very dark glossy green with minute reticulation, midrib slender, impressed, ribs filiform, prominulous in a groove; below very densely light golden brown lepidote, scales minute, flat with rather irregular margin. Petiole 10-15 mm slender. Flowers on the bare branches, consisting of a short thick main peduncle with few, 2-3 cm long, thick branches, each bearing 2-4 flowers. Pedicels stout, 4-5 cm long, gradually thickened apically. Flower buds initially depressed globose and ultimately subovoid-globose. Calyx urn-shaped, the 5 sepals connate, apically with 5 triangular, acute, 5-7 mm long broad lobes, lepidote outside. Petals free, white, glabrous, large, consisting of a thick, flat, stiff, wide, clawlike part, gradually widened apically and ending in a strongly reflexed much thinner spathulate-orbicular apical part. Stamens in 5 phalanges of 5-7 stamens each, the filaments fused in their basal half, the free parts 2-3 cm long, bearing clumps of one-celled anthers. Ovary oblong, densely minutely lepidote, showing a slight longitudinal furrow. Style reddish, glabrous, rather fleshy, up to 5 cm long, surpassing the stamens, cylindrical with conspicuous capitellate stigma. Fruit immature with numerous very hard and sharp, sub pyramidal thorns, the latter covered by numerous very tiny fimbriate scales.
DISTRIBUTION
Mt. Leuser National Park, North Sumatra, described after a cultivated specimen in the private garden of D. Kostermans in Gadok near Bogor, Java.
PHENOLOGY
Flowers open in the afternoon and drop in pieces during the night. They have no smell and no nectar. Pollinators are perhaps bats and night moths. The flowers had always a few black ants.
The branch basis are surrounded by a high annulus of tissue, free from the branch, as if they had to push the bark aside when developing.
The species is outstanding among the 3 other species so far known by the large flowers. From REINWARDTIA, a journal on taxonomic botany, plant sociology and ecology. Published by Herbarium Bogoriense.
DATE: March 1994
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