Coelostegia Notes

Coelostegia borneensis Becc.
Coelostegia chartacea Soeg.Reksod
Coelostegia griffithii Benth.
Coelostegia kostermansii Soeg.Reksod.
Coelostegia montana K.Sidiyasa
Coelostegia neesiocarpa Soeg.Reksod.

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Coelostegia is a small genus of trees related to the Durians (Durio), found in western Malesia (Sumatra, Malaysia and Borneo), monographed by Soegeng-Reksodihardjo in 1960. Its placement within Helicteroideae and Durioneae is confirmed by ITS nrDNA and ndhF cpDNA sequence evidence.

Coelostegia griffithii is from Sumatra and Malaysia; the remaining species are from Borneo. Coelostegia sumatrana Becc. is a synonym of Coelostegia griffithii. The identity of C. macrantha Kosterm. from Sumatra is unknown, but it might be the same plant as Durio macrantha Kosterm. (The herbarium specimen at NYBG comes from a tree grown from a 1991 collection, by Kostermann, of a new species; he described Durio macrantha in 1992. Perhaps he changed his mind about the appropriate genus in the intervening months.)

Coelostegia is used a timber tree. As such it is known as black durian. It is suitable for light construction, door and window frames, wooden sandals, flooring, planking, plywood, sliced veneer and furniture2.

Coelostegia griffithii Benth.

Coelostegia griffithii is a tall tree. The leaves are simple, unlobed, with an entire margin, and a scaly indumentum on the underside. They are oval or oblong, pinnately veined, 2½-3 in long by 1 in wide, and borne on a ½ inch petiole. The short-pedicelled (subsessile) flowers are borne in fascicles, from old wood. They have an epicalyx of 3 or 4 connate bracteoles, forming a cup shaped tube. The calyx is composed of 5 lanceolate sepals, much longer than the bracteoles, and connate for half their length to form a 5-lobed, 5-pouched cup. The corolla is reduced. The stamens are borne in 5 clusters.

Images

herbarium specimen of Coelostegia macrantha Kosterm. at NYBG

References

  1. Jarvie, J.K. and Ermayanti, Tree Genera of Borneo - Descriptions and Illustrations (1996 onwards)
  2. Malaysian Timber Council (1992 onwards)
  3. Joseph Dalton Hooker, The flora of British India (1875)

© 2003, 2010 Stewart Robert Hinsley