Rediscovery of Curcuma sumatrana ( Zingiberaceae ) endemic to West Sumatra

A recent exploration of Sumatra resulted in the re-collection of Curcuma sumatrana, an endemic Zingiberaceae species of unclear identity that was first described by Miquel nearly 150 years ago. The history of this species is discussed, a detailed description with a colour plate is provided and a lectotype is designated. Curcuma sumatrana currently qualifies under IUCN assessment as vulnerable, but due to the decline of its habitat, it is likely to fulfil the criteria as endangered in near future. As there is no comprehensive revision of the family Zingiberaceae for Sumatra in progress, it is meanwhile important to make accessible the characteristics of this endemic species to facilitate its proper identification and conservation management.


INTRODUCTION
When reading the early taxonomic literature on Zingiberaceae, it is often difficult to get a clear picture of the identity of species due to brief and sometimes misleading descriptions.These descriptions were often based on few collections without consulting the type or the type was fragmentary.In addition, misleading synonymies were established without access to living material.This led to much confusion, particularly in the genus Curcuma (Leong-Škornic ˇková et al. 2008a, b).Numerous earlydescribed species, particularly those from more remote areas, have not been re-collected recently, and their morphology is either completely unknown or they are considered synonyms of some commonly cultivated taxa.
During the exploration of West Sumatra, an interesting Curcuma species with orange-red inflorescences was collected in the wild at two different localities (A.Anggara & R. Burlis 59 and M. Ardiyani et al. 189).At first glance, the bright orange-red inflorescence resembled that of Curcuma roscoeana Wall.from which it differs in the arrangement of bracts, which are not in pronounced vertical rows but in spiral.Closer examination of the flower revealed more differences, particularly in the structure of the anther, that has two spurs and no crest and also by the shape and colour of labellum (for comparison see colour plate of C. roscoeana in Škornic ˇková & Sabu 2005).Further study of the protologues of Curcuma species described from the Malesian region yielded an unproblematic match with the incomplete description of C. sumatrana.In addition, unlike many other Curcuma species, no drawings, paintings or photographs were ever published, adding to the unclear identity of this species.
Curcuma sumatrana was originally described by Miquel (1861) in a supplement to his 'Flora van Nederlandsch Indië' based on a specimen collected by Diepenhorst in Priaman, West Sumatra (at a distance of 20-40 km from our recent collections).The Latin description consists of nine lines outlining the basic features of which the most informative characters are: oblique rhizomes, usually two leaves on whole plant with long petioles and a terminal inflorescence with loosely arranged bracts that are pale or yellow at the base and red at the top.
The next short note on this taxon appeared some 20 years later in Gardeners' Chronicle where Brown (1882) explained that C. sumatrana had been introduced by Mr. Curtis from Sumatra into Messrs.Veitch nurseries and that a specimen was donated to Kew herbarium.The note also includes a brief description in English that fits Miquel's original description.Three specimens are present in Kew herbarium.One seems to be an original Curtis collection, while the other two are specimens made in 1882 and 1884 from material cultivated in Messrs. Veitch's nursery; the former is annotated by Brown and served the basis for his Gardener's Chronicle article.It is known that Curtis collected between 1880 and 1882 in Padang Highlands in West Sumatra, which is not far from the type locality of C. sumatrana and falls into current distribution range of the species.
In 1899, Schumann placed C. sumatrana as a synonymy of C. viridiflora Roxb.based on the descriptions, but in his comprehensive treatise of the Zingiberaceae in 1904 he realized that C. viridiflora is a taxon possibly synonymous with C. longa and then treats C. sumatrana as a separate species.He merely quoted parts of Miquel's description and noted that the description is imperfect and that he was unable to trace an original specimen, implying that he was not clear about the identity of C. sumatrana.Ridley (1899) thought that C. sumatrana was a synonym of C. zedoaria.Later, Valeton surmised that the shape of the bract made Ridley think this, and in his account (Valeton 1918) C. sumatrana was placed under "incompletely known species".He examined the specimen from Diepenhorst No. 1327 in BO and commented that C. sumatrana is closely allied to C. petiolata, but did not mention that this was the type specimen.Since then, no other author has paid attention to this species.
During revisions of Curcuma material in numerous herbaria, several sheets of this taxon have been discovered at ANDA,
Distribution & Ecology -Endemic to West Sumatra, known only from Maninjau, Sianok, Lembah Anai, Kayu Tanam, and Ulu Gadut from the Barisan Range.No data on habitat preference are available for the early collections, but recent collections originate from secondary forests at elevations between 100-500 m, often with many Laportea sp.(Urticaeae).This raises a question whether C. sumatrana is native to Sumatra.Unlike numerous vegetatively reproducing polyploid Curcuma species, which may be found naturalized all over Asia, the majority of seed-setting species from the subg.Curcuma are rather restricted in their distribution.They may colonize secondary habitats, but will not naturalize easily out of their natural range.Curcuma sumatrana is a seed-setting species (formation of fruits observed) and in spite of our extensive revision of Curcuma herbarium material (Leong-Škornic ˇková et al. 2010) the species has not been found outside West Sumatra.We therefore believe that this species is native to Sumatra.
Phenology -Flowering May to September; fruiting observed from July onwards.
Uses -Leaves are used for wrapping the flesh of durian fruit, which is then fermented to make a cooking ingredient called Pekasam.The water from boiled leaves is used to cure skin problems (itchiness).
IUCN assessment -The area of distribution of C. sumatrana is about 1 600 km 2 and consists of less than 10 localities, mainly in the Barisan Mountain range (between Maninjau Lake and Ulu Gadut).Based on the IUCN Red List criteria (IUCN 2001), we propose a conservation status of Vulnerable (VU B1ab(iii)).However, as the habitat of C. sumatrana is affected by human activities and is in decline, the taxon is likely to qualify in the near future for the Endangered category.

Plate 1
Curcuma sumatrana Miq.a. Abaxial and adaxial side of leaves; b. habit; c. inflorescence; d. flower dissection; e. flowers in bracts; f. rhizomes (all: M. Ardiyani et al. 189).-Photos by M. Ardiyani.sourcing related references.The linguistic help with English from Dr. Gillian Dean and comments of an anonymous reviewer are greatly appreciated.
Abstract A recent exploration of Sumatra resulted in the re-collection of Curcuma sumatrana, an endemic Zingiberaceae species of unclear identity that was first described by Miquel nearly 150 years ago.The history of this species is discussed, a detailed description with a colour plate is provided and a lectotype is designated.Curcuma sumatrana currently qualifies under IUCN assessment as vulnerable, but due to the decline of its habitat, it is likely to fulfil the criteria as endangered in near future.As there is no comprehensive revision of the family Zingiberaceae for Sumatra in progress, it is meanwhile important to make accessible the characteristics of this endemic species to facilitate its proper identification and conservation management.BO, E and K, but all were either unidentified or misidentified as other Curcuma species.On the other hand, several specimens from Sumatra collected by Lörzing (Lörzing 12603, L, Lörzing 5775, BO, L) that are identified as C. sumatrana, are collections of some cultivated Curcuma species, most probably C. viridiflora.