Saribus brevifolius is a species of palm tree in the genus Saribus, which has only been found in the Kawe and Gag Islands in the archipelago of the Raja Ampat Islands, which lie off the north-west tip of the Bird's Head Peninsula in Indonesia's West Papua province. It was only discovered in 2002 during an expedition funded by The Nature Conservancy. The palm grows along the coasts of these two tropical islands on small ridges composed of ultrabasic rock. It is a moderately-sized fan palm with smallish and regularly segmented leaves and a smallish inflorescence in the crown. The inflorescence is not longer than the leaves, and split at its base into three main branches with one or more sub-inflorescences, these containing red flowers with pink anthers. The ends of S. brevifolius leaf segments are rigid and have a bifurcate cleft 1-4% of the segment length.
Taxonomy
Saribus brevifolius was only relatively recently described as a new species. It was discovered in 2002 during a 'rapid ecological assessment' survey of the Raja Ampat Islands by The Nature Conservancy. The holotype was collected by an international team of plant collectors on the Kawe Islands north-west off Waigeo island. The collection number is JPM#8171. The collection number JPM#8224 is from the same population, and was collected at the same time: it is of the young fruit of the palm.
The formal species description was done by John Leslie Dowe and Johanis P. Mogea in 2004. At the time the genus Saribus, which had been created in the 19th century, was not recognised, and the species was described as Livistona brevifolia. Soon, however, new phylogenetic research comparing the DNA of different species of Livistona was published, which found that the genus was polyphyletic. Thus the authors, Christine D. Bacon and William John Baker, resurrected, i.e. re-recognised, Saribus, and the species was moved to this genus by them in 2011.
The holotype is housed at the Herbarium Bogoriense in Indonesia. Isotypes were also deposited at the herbarium at the Royal Botanic Gardens, Kew, the herbarium of the University of Papua in Manokwari, the National Herbarium of the Netherlands in Leiden and the William and Lynda Steere Herbarium of the New York Botanical Garden.
Description
Habitus
This plant is a hermaphrodite fan palm. This palm tree can become quite large, it grows up to in height, often shorter, with an at least trunk diameter at breast height, gradually becoming more slender towards the top, up to 10 cm in diameter. The palm grows with a solitary trunk. The leaf or petiole scars left behind on the trunk are slightly raised, and light grey in colour; the internodes between the scars are narrow. The stubs of the petioles are not persistent, i.e. they do not remain clinging onto the trunk for long. There are sixteen, sometimes up to forty, leaves in the roundish crown.
Leaf
It has smallish leaves for a Saribus palm. The leaf-sheath is fibrous. The petiole is some 110 cm in length. It is 29 to 42mm wide where it connects to the trunk, 12 to 13mm wide at the other end, slightly arching, and green. The upper, the adaxial side, is slightly concave, glabrous, with waxy, white scales on this top surface -which eventually fall off, whereas the underside, the abaxial side, is rounded. The margins of the petiole lack spines. The base of the petiole is covered in a single woven layer of coarse, brown fibres. These fibres remain until the leaf falls off, then begin to disintegrate. The 'appendages', fibres forming tongue-like straps on either side of the leaf-base, are 12 to 25 cm long. The hastula, which is a lip-like structure found in palms at the junction of the petiole and the leaf blade, is poorly developed, strongly asymmetric, and lobed.
The leaf blade, or lamina, is costapalmate, its rachis is curved, and about 25 cm long. It is regularly divided, for 17-53% of its length, into 22 to 25 segments. The leaf blade is semi-circular, rigid, moderately undulate (wavy) in profile, 55 to 62 cm in length and 45 to 55 cm wide. Its upper side is coloured mid-green, the underside light green. Each segment is bifurcated at its apical tip, with a split being 1-4% of the length of the segment. The segments are 2 to 2.5 cm wide at the point where the segments split from each other and the rest of the leaf blade. The segments are held rigidly aloft to their ends, and are not drooping. In each segment there are five to seven parallel veins on each side of the midrib. There are also transverse veins, which are thinner than these parallel veins.