Sphaerobambos, a New Genus of Bamboo (Gramineae-Bambusoideae) from Malesia

Abstract

In preparing an account of the bamboos of Sabah, East Malaysia, I was unable to decide to which genus one sterile specimen (Tiong SAN 88660) belonged. It was collected from Lohan village near Ranau. In 1979 when I went collecting around Ranau, I did in fact see bamboo clumps on a small hill near Lohan village but made no collections; from a distance this bamboo looks like Schizostachyum blumei Nees or S. latifolium Gamble which are common in the area. In February 1986 I revisited the areas near Telupid and Ranau together with Mr P. S. Shim (SAFODA) and Mr K. M. Wong (then of FRIM, Kepong). We stopped and collected the bamboo I saw in 1979, in a sterile state; it matches Tiong SAN 88660. I still could not place it in any known genus. It is a scrambling bamboo; the culm has thin walls and the branches are many at each node with the primary branch dominant. These primary branches are not always dormant, some developing and elongating to become as large as the main culm and behaving like it by producing branches at each node. The sheaths of young culm-shoots and of young primary branches are hairy and have very narrow, almost inconspicuous rugose bases. The plant looks like a species of Dinochloa, but the culms do not climb and are only slightly zig-zag. Later on that day we came to the muchdisturbed Lohan River, and found near the rocky river bank a bamboo clump about m tall with a few erect culms and with flowers and fruits. This matched the sterile bamboo collected earlier. The inflorescence is composed of pseudospikelets, the spikelet consisting of several florets like that of Bambusa. The fruit is globose with a large embryo resembling that of Dinochloa but the plumule and radicle are basal rather than lateral. The palea is longer than the lemma in the mature spikelet, 2-keeled with narrow wings along the keels such as can be found in some species of Guadua from the New World. The anthers have apiculate tips. Later I found that one of the leafy branches of the first collection bore a young inflorescence. These features indicate that this bamboo belongs to an undescribed genus which I propose to name Sphaerobambos, with S. hirsuta as the type species. Sphaerobambos is apparently related to Dinochloa and Melocalamus by the structure of the fruit. It differs from both genera in having multi-flowered spikelets. Without fruit Sphaerobambos can be easily confused with Bambusa by having multi-flowered spikelets. It differs from the latter, however, by having the palea longer than the lemma and the keels of the palea winged (Table 1). The examination of other specimens from neighbouring islands deposited in the Herbarium at