On the occurrence of Nitella myriotricha A.Braun ex Kützing, 1857 ssp. acuminata D.Subramanian, 1999 (Charophyceae: Charales: Characeae), from eastern India

: Nitella myriotricha A.Braun ex Kützing ssp. acuminata D.Subramanian 1999 has been recorded from different localities of West Bengal, eastern India. It is the first report of the taxon outside its original locality of occurrence at Kummidipoondi (Tamil Nadu) by Subramanian in 1999. The possibilities of endemism and origin of variations in this species have been discussed.

ISSN 0974-7907 (Online); ISSN 0974-7893 (Print)  (1824) is a cosmopolitan genus of Charophyta that grows in undisturbed aquatic ditches, lakes, and bogs. It is easily identified due to the position of its reproductive organs even in macroscopic form. In comparison to its sister genus Chara L. it prefers to grow in low nutrient, soft and slightly acidic waters (Bryant & Stewart 2011;Graham et al. 2016). In contrast to Chara it is either slightly lime-encrusted or un-encrusted genus (John & Rindi 2015). It is less rigid, excorticated and lack spines. If we consider the position of reproductive organs it is just reverse to that of Chara. In both the genera sex organs are lateral in position, in Chara, nucule is above & globule is below while position is just reverse in Nitella.
Nitella Agardh (1824)  During the systematic study on the charophytes of eastern India the authors recorded N. myriotricha ssp. accuminata D.Subramanian from several localities of West Bengal (Image 1).

Material and Methods
The samples were collected from Prantik canal, Bolpur, Birbhum District, West Bengal, India. Similar populations of the taxon were also recorded from Bhaska, Lakhipriya Alis Nutandi & Saheb Bandh, Purulia District, West Bengal. Ten samples from these four localities have been studied. Samples were washed vigorously by gentle cleans in running water and preserved in 4% formalin. Conductivity, pH, water temperature, salinity, TDS, and habitat were also recorded at the time of sample collection. Multi-parameter PCSTestr TM 35 device was used to measure the ecological data. Dissolved sodium, potassium, and calcium of the water sample were measured with the help of flame photometer128 and dissolved oxygen was measured with titration method. A small portion of the sample was taken on a clean petridish and set under the Zeiss Stemi 508 stereozoom research microscope having digital camera attachment with standard scale. Microphotography was done and measurements were taken with the Zeiss Zen 2.6 software. Detailed taxonomic study was done by microscopic observations for identification of species. The identification of species was done with the help of standard monograph (Subramanian 2002). (Image 1 A-F) Plant body 8-12 cm in height; monoecious; bright green in colour; whole plant body entirely covered with dense mucilaginous cloud; axes 400-630 µm in diameter, internodes longer than branchlet, 6 branchlets, unequal in length; 7 dactyles, acute in shape; nucule and globule are present at the second and third branchlet nodes: no sex organs at shorter branchlets; antheridium large, one per node, orange in colour, 320-470 μm in diameter; oogonium large, 332 µm long, 240 µm broad, yellowish green in colour, convolutions 8-9; corona cells in two tiers 40-43 μm in broad & 42-45 μm long.

Nitella myriotrichia
Our specimen appears to be narrower, may be due to different climatic regime.

Discussion
As far as the distribution of Nitella myriotricha is concerned, it is known from very few localities of the world, Zealand. It reveals two possibilities: 1. Endemism may be a key factor for its occurrence, 2. Continental drift may be another factor when actually the Indian and Australian subcontinents were united (Wegner 1924(Wegner , 1929Demhardt 2005) and separation of these subcontinents may have provided opportunity to the Indian species to evolve into two new subspecies. The possibility of endemism is guessed due to the fact that the occurrence of the species has been noted in India and Australia only. If we apply the Vavilov's (1926) principle here the origin of this species may have occurred in Indian subcontinent because variations into subspecies have been noted in India only.

Conclusion
In India, species of Characeae are poorly described and more extensive floristic studies need be undertaken, particularly in remote areas of the country. Only few taxa have been reported from southern India. But in eastern India particularly in West Bengal floristic study is very poor. In this study Nitella myriotricha ssp. acuminata have been collected from Prantik, Bolpur, Birbhum District, West Bengal. This is the first report of the taxa outside the original site. A mucilaginous cloud was present over here. This is the unique identifying character of this species.

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