ELODEA NUTTALLII (PLANCH.) ST. JOHN (HYDROCHARITACEAE) - A NEW ANGIOSPERMIC RECORD FOR BANGLADESH

Elodea nuttallii (Planch.) St. John has been explained as a new report from Bangladesh. The taxonomic description including flowering, fruiting, ecology and distribution of the species are elaborated here.


Introduction
In Bangladesh, freshwater wetlands mainly occupied by haors which cover major areas of Kishoreganj and greater Sylhet districts.A large number of aquatic macrophytes have been found of these habitats.Alfasane et al. (2010Alfasane et al. ( , 2013Alfasane et al. ( , 2019Alfasane et al. ( , 2020Alfasane et al. ( , 2021Alfasane et al. ( , 2022Alfasane et al. ( , 2023) ) have been reported 11 species of aquatic macrophytes either as new to science, new records and new occurrence including the present species from Bangladesh.Recently Alfasane et al. (2023) reported Elodea canadensis Michx.from Hakaluki haor, Bangladesh.It indicates a lot of aquatic macrophytes are not yet listed in the biodiversity components from Bangladesh.There are lots of physic-chemical, socio-ecological, economic and cultural importance present of the haors of Kishoreganj district (Kishoreganj Zilla, 1993).This haor district contains 13 Upazillas where a total number of 85 haors are present.The total area occupied is about 75000 hectare (DAE, 2003(DAE, -2010)).The four upazillas namely, Austogram, Mithamoin, Itna and Nikli are fully bounded by haors.On the other hand five upazillas namely, Bajitpur, Bhairab, Karimganj, Kuliarchar and Tarail are partially bounded by hoars.The agricultural sector is the prime focuses around the haors of Kishoreganj district (BHWDB, 2016).Mahitulpa Haor from Austagram upazila of Kishoreganj district covers the approximate area 549 ha.This haor is different in geographical position, morphometric nature and biodiversity standpoint.This haor play a great role for the socio-economic importance of Bangladesh.Due to environmental degradation and losses of biological diversity a taxonomic survey of aquatic plants with hydrobiological study has been made of the Mahitulpa Haor from Kishoreganj districts.
A total of 16 genera and about 100 species have been recorded under Hydrocharitaceae family.The members of this group mostly in aquatic and cosmopolitan in nature.A total of 8 genera and 14 species have been reported from Bangladesh so far (Alfasane et al., 2010(Alfasane et al., , 2022(Alfasane et al., , 2023;;Siddiqui et al., 2007) from Hydrocharitaceae.In the present paper, the first report of Elodea nuttallii (Planch.)St. John from Bangladesh has been made.

Materials and Methods
The samples were collected from the Mahitulpa Haor from Mankhola village of Austagram Upazila of Kishoreganj district of Bangladesh from 01.02.2024 to 05.02.2024.The collections were made at the latitude 24°18'4.78"Nand longitude 91° 1'43.28"E.The samples were collected from the depth between 2.0-4.0 m of the littoral area.The samples were then put in a collection bag mixing with water.
The detailed taxonomic work and autecological parameters has been made in the National Professor A.K.M. Nurul Islam Laboratory, Department of Botany, University of Dhaka.The exsitu conservation of the Elodea nuttallii was done in the Botanical garden of Curzon Hall campus, University of Dhaka.
There is no report of E. nuttallii was found of the studied literature (Alfasane et al., 2023;Hooker 1888;Khan and Halim 1987;Prain 1903;Siddiqui et al. 2007) indicating that this species is a new record for Bangladesh.

Distribution and ecology
In Bangladesh, it is so far only confined to the Mahitulpa haor of Kishoreganj district.Elodea nuttallii was found in the littoral portion of the haor under submerged condition at the depth up to 6 ft, calm water with oligotrophic nature.They prefer to grow with sufficient light.A total of 27 samples were collected from 9 stations for physico-chemical and biological analyses of the Mahitulpa haor.The mean values of the ranges of different physicochemical parametrs were found during the investigation as follows: air temperature 30.25-32.52°C,water temperature 27.28-30.45°C,Electric Conductivity 78.87-98.57µS/cm, Total dissolved solids 40.58-52.67mg/l, pH 7.08 to 7.15, Alkalinity 0.78-0.90meq/l, turbidity 1.15-1.38NTU, Biochemical oxygen demand of BOD 5 0.95-2.95mg/l, Dissolved oxygen 10.31-14.25 mg/l, Nitrate-nitrogen (NO 3 -N) 0.25-0.40,Total suspended solids 17.14-22.58mg/l, Soluble reactive phosphorus 17.58-20.36µg/l, Soluble reactive silicate 5.45-6.46mg/l, Fl -0.09-0.15mg/l, Na + 0.09-0.13mg/l, SO 4 2-8.56-10.21mg/l, K + 0.18-0.20,NH 4 + 0.17-0.19mg/l,NO 2 -0.08-0.13mg/l, Cl -0.45-0.52 mg/l, Fe 2+ 0.14-0.25 mg/l, Mn 2+ 0.17-0.24mg/l, Mg 2+ 0.28-0.34mg/l and Ca 2+ 0.53-0.75mg/l.E. nuttallii was collected in association with other aquatic plants namely, Ceratophyllum, Potamogeton, Myriophyllum, Hygroghiza and Hydrilla.As the North American native of Elodea nuttallii which were introduced in Europe.It is vastly used in aquarium as an ornamental plant.In 1939, E. nuttallii had been reported from Belgium and different countries rest of the world (Cook and Urmi-König, 1985;Nino et al., 2005;Simpson, 1984Simpson, , 1990;;Xu et al. 2007).It has massive growth and invasiveness due to the vegetative propagation.The differences between the Elodea canadensis and E. nuttallii were found in the inflorescences.The male flowers of E. nuttalllii were found to be sessile and these were released at the time of anthesis.On the other hand a minute floral tube present in the female flower rather than that of Elodea canadensis.The leaves of E. nuttalllii shorter, folded and bent like twisted form row along the midrib and less wider than that of E. canadensis.

Fig. 1 (
Fig. 1 (A-E): A. Geographical area of the Mahitulpa haor where showing the collection site of (MT1, Sentinel 1 SAR image) of Elodea nuttallii (Planch.)H. St John; B-D.Habit and habitat of E. nuttallii , anchoring and floating under submerged condition; E-F.Mature plants with the arrangement of leaves (Scale= 5 mm).