ANGIOSPERM FLORA OF RAMPAHAR RESERVE FOREST UNDER RANGAMATI DISTRICT IN BANGLADESH . I . LILIOPSIDA ( MONOCOTS )

A systematic floristic study of Rampahar reserve forest under Rangamati district in Bangladesh has revealed 89 monocot (Liliopsida) taxa belonging to 66 genera under 15 families. Out of these recorded taxa, 73 are herbs, 9 climbers, 3 bamboos, 3 reeds and 1 tree species. The area harbours 11 threatened species of the country. Updated nomenclature with full reference citation, habit and representative specimen have been provided for each species. Well known synonyms and local name(s) have also been given in some cases. Introduction Rampahar together with Sitapahar was declared as a first reserve forest within the Chittagong Hill Tracts (CHTs) in 1875 (Anonymous, 1960). The under explored forest area of Rampahar, represents tropical rain forest mainly of evergreen type of vegetation, is situated in Kaptai upazila under Rangamati district. Administratively, the area belongs to Kaptai Forest Range under the management of Rangamati South Forest Division. It lies between 22°26 ́ & 22°38 ́ North and 92°08 ́ & 92°17 ́ East. The hilly area is occupying approximately 648 hectares of natural forest covers. Rampahar reserve forest is bounded by the river Karnaphuli on the South and by degraded hills and a tribal settlement on the West. Teak (Tectona grandis) plantation of Chitmarom Forest Beat lies on the East and North which is being separated by a channel known as 'Baluchhara'. Geologically, the area belongs to the Pliocene and Miocene epoch of the tertiary period. The configuration of the ground is very irregularly rugged and consists of a series of ridges and valleys running more or less from north to south. The level of valley bottoms ranges from 30 to 90 meters above the sea level and maximum elevation is about 500 m. Soil is mainly yellowish-brown to reddish-brown loams which grade into broken shale or sandstone at a various depth (between 30120 cm). The valley soil is mainly acid loams and clays subject to seasonal flooding. The humus composition is high but its degree of accumulation varies from place to place depending on topography. Usually more deposition is found on flat land and on the bed of channel (chhara) and less on the undulating hills. The climate of the study area is tropical warm-humid and which is greatly influenced by the monsoon. The average temperature ranges from 19.9°C to 28.3°C and the average annual rain fall is about 2,900 mm (Uddin et al., 1998). About 90% of the total rainfall occurs in the period between June-September, whereas, the months of December to March are particularly without rain. The mean relative humidity is rather high and usually remains between 66-85% throughout the year. During the winter, the perennial springs (chhara) and the river Karnaphuli are the source of water supply in the reserve. However, with abundance of rainfall during the rainy season there is no dearth of water for vegetation during that period, which is incidentally the growing season for the plants. Corresponding author. Email: nsarder@yahoo.com Department of Botany, University of Dhaka, Dhaka 1000, Bangladesh.


Introduction
Rampahar together with Sitapahar was declared as a first reserve forest within the Chittagong Hill Tracts (CHTs) in 1875 (Anonymous, 1960).The under explored forest area of Rampahar, represents tropical rain forest mainly of evergreen type of vegetation, is situated in Kaptai upazila under Rangamati district.Administratively, the area belongs to Kaptai Forest Range under the management of Rangamati South Forest Division.It lies between 22°26´ & 22°38´ North and 92°08´ & 92°17´ East.The hilly area is occupying approximately 648 hectares of natural forest covers.
Rampahar reserve forest is bounded by the river Karnaphuli on the South and by degraded hills and a tribal settlement on the West.Teak (Tectona grandis) plantation of Chitmarom Forest Beat lies on the East and North which is being separated by a channel known as 'Baluchhara'.Geologically, the area belongs to the Pliocene and Miocene epoch of the tertiary period.The configuration of the ground is very irregularly rugged and consists of a series of ridges and valleys running more or less from north to south.The level of valley bottoms ranges from 30 to 90 meters above the sea level and maximum elevation is about 500 m.Soil is mainly yellowish-brown to reddish-brown loams which grade into broken shale or sandstone at a various depth (between 30-120 cm).The valley soil is mainly acid loams and clays subject to seasonal flooding.The humus composition is high but its degree of accumulation varies from place to place depending on topography.Usually more deposition is found on flat land and on the bed of channel (chhara) and less on the undulating hills.
The climate of the study area is tropical warm-humid and which is greatly influenced by the monsoon.The average temperature ranges from 19.9°C to 28.3°C and the average annual rain fall is about 2,900 mm (Uddin et al., 1998).About 90% of the total rainfall occurs in the period between June-September, whereas, the months of December to March are particularly without rain.The mean relative humidity is rather high and usually remains between 66-85% throughout the year.During the winter, the perennial springs (chhara) and the river Karnaphuli are the source of water supply in the reserve.However, with abundance of rainfall during the rainy season there is no dearth of water for vegetation during that period, which is incidentally the growing season for the plants.
Over the past few decades, several floristic inventories have been progressed throughout the country.Those had resulted in the compilation of a number of checklists viz.Khan and Banu, 1969;Khan et al., 1994;Rahman and Hassan, 1995;Rahman and Uddin, 1997;Uddin et al., 1998;Uddin and Rahman, 1999;Khan and Huq, 2001;Uddin and Hassan, 2004;Uddin and Hassan, 2010.Even though, many areas of the country have been either poorly investigated or remain unexplored till now.Floristic collections are essential for expanding the holdings from those under-represented areas.Recently, the Forest Department of Bangladesh has declared the area as a part of Kaptai National Park and has been taking various initiatives for the conservation and sustainable management of the plant genetic resources of the area.However, no published floristic account has been prepared for the Rampahar area so far.The present study has been undertaken aiming to have an inventory of angiosperm flora of Rampahar Reserve Forest.This floristic inventory will generate baseline information for any conservation and management activity of the area.

Materials and Methods
The present work deals with the monocot (Liliopsida) species of the Rampahar area and is mainly based on plant specimens collected through extensive field survey.The floristic inventory of Rampahar Reserve Forest was done by using area maps and regular field visits, accompanied with the collection of fertile specimens of all available plant species.A total of 19 field trips were made during 2001-2008 and over 2,000 plant specimens were collected.The collected specimens were examined at the Bangladesh National Herbarium (DACB), Dhaka University Salar Khan Herbarium (DUSH) and Bangladesh Forest Research Institute Herbarium (BFRIH).Some difficult specimens were identified during the visits to herbaria at the Royal Botanic Garden Edinburgh (E), the Royal Botanic Gardens Kew (K) and the Central National Herbarium, Kolkata, India (CAL).The specimens have been preserved at the DACB, DUSH and BFRIH.The families have been arranged according to Cronquist's system of classification (Cronquist, 1981).The genera and species under each family have been arranged alphabetically.To keep the paper less voluminous, valid name with original citation of each taxon with only well-known synonyms in few cases, local name (if available), habit and only one representative specimen (RS) number (collected from the study area -Rangamati district, Rampahar, Kaptai) has been provided.The species names have been checked with Hooker (1890Hooker ( -1894Hooker ( , 1897)), Prain (1903), Heinig (1925), Raizada (1941), Sinclair (1956), Siddiqui et al. (2007) and Ahmed et al. (2008).

Discussion
A total of 89 taxa of monocot (Liliopsida) under 66 genera and 15 families have been recorded for the Rampahar Reserve Forest.The study has revealed that only nine species are epiphytes and the remaining terrestrial.On the other hand, the number of perennial and annual species are 72 and 17, respectively.The study has also found that Poaceae is the largest family with 27 species followed by Orchidaceae (13 species), Cyperaceae (11 species) and Zingiberaceae (10 species).Eight families (viz.Arecaceae, Musaceae, Costaceae, Marantaceae, Haemodoraceae, Liliaceae, Taccaceae and Smilacaceae) are represented each by a single species.The genus Dioscorea appears as the largest genus represented by seven species.