PLAGIOSTACHYS NICOBARICA ( ZINGIBERACEAE ) , NEW GENERIC RECORD AND A NEW SPECIES FROM THE NICOBAR ISLANDS , INDIA

Plagiostachys nicobarica, a new generic record and a new species from the Nicobar Islands, India, is described and illustrated. The genus, so far known from China, Indonesia, Malaysia, the Philippines and Thailand, is now reported from India.


INTRODUCTION
The family Zingiberaceae, one of the largest monocotyledonous families of the Indian subcontinent, is represented by 22 genera and about 180 species (Jain & Prakash 1995).Even though several notable studies on this family have been carried out during the past several years in India, survey of remote areas has been regularly bringing out new discoveries (Sabu & Mangaly 1991, Jain & Prakash 1995, Srivastava 1998, Skornickova & Sabu 2005a, b, Sabu 2006).Srivastava (1998) carried out remarkable work on the Zingiberaceae of Andaman & Nicobar Islands and enumerated 23 species in 10 genera, both wild and naturalized.Recent work by Larsen (1997), William et al. (2004) and Skornickova & Sabu (2005a, b) have reduced the total number of genera to 19 from 22 by the transferring of Curcumorpha to Boesenbergia, Mantisia to Globba and Paracautleya to Curcuma.
As part of a Department of Science and Technology (DST) project, the authors visited the Andaman Islands in April 2002 for the study of Gingers in that region.While studying the herbarium specimens at the Andaman & Nicobar Circle of the Botanical Survey of India at Port Blair (PBL) four collections (2977,3832,3933,7162) drew the attention.Two of them (3832,3933) have been misidentified at family level and placed under Marantaceae.The other two (2977, 7162) were determined as Cautleya Hook.f.But the position of the inflorescence and scanty notes on the labels clearly indicated that they belong to the genus Plagiostachys Ridl.However, the notes on the labels are insufficient for species delimitation.
Our team again visited the Nicobar Islands in 2003 and 2007 to collect Plagiostachys specimens.They could collect specimens in fruiting and flowering stage.The rhizomes were planted in the Calicut University Botanical Garden (CUBG) and flowered in November 2003.A critical study of specimens in comparison with other species has  proved that this plant is distinct from described species.Specimens and photographs were sent to Prof. Kai Larsen, Aarhus University for confirmation.

Plagiostachys nicobarica
Etymology -The specific epithet 'nicobarica' indicates the place of collection, the Nicobar Islands.
Notes -Plagiostachys nicobarica is allied to P. sumatrensis but differs in leaf size, branching of inflorescences, flower colour and sizes of flower parts and fruits (Table 1).
The species is only known from the type locality and surroundings.These areas are at present under water from the Tsunami flood.Approximately 60% of the specimens are lost and remaining specimens are in danger of being wiped out at any time.