Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2025 | 17(8): 27378–27383

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)

https://doi.org/10.11609/jott.9479.17.8.27378-27383

#9479 | Received 05 November 2024 | Final received 29 July 2025 | Finally accepted 10 August 2025

A new variety of Chara corallina Willd. (Charophyta: Characeae) from Kamrup District, Assam, India

Partha Pratim Baruah ¹, Shaswatee Bhattacharjee ², Nilamjyoti Kalita ³ & Bishmita Boruah ⁴

^1–4 Department of Botany, Gauhati University, Guwahati, Assam 781014, India.

¹ ppbaruah@gauhati.ac.in, ² shaswatee1231@gmail.com, ³ nilamjyotikalita2014@gmail.com (corresponding author), ⁴ bishmitaboruah27@gmail.com

Editor: Jai Prakash Keshri, The University of Burdwan, Burdwan, India. Date of publication: 26 August 2025 (online & print)

Citation: Baruah, P.P., S. Bhattacharjee, N. Kalita & B. Boruah (2025). A new variety of Chara corallina Willd. (Charophyta: Characeae) from Kamrup District, Assam, India. Journal of Threatened Taxa 17(8): 27378–27383. https://doi.org/10.11609/jott.9479.17.8.27378-27383

Copyright: © Baruah et al. 2025. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

Funding: Self funded.

Competing interests: The authors declare no competing interests.

Acknowledgements: The authors are grateful to head, Department of Botany, Gauhati University for providing laboratory facilities developed under DST-FIST, UGC-SAP to carry out the research work. The authors are also thankful to head, Department of Geology and Rakesh Talukdar, Department of Chemistry, Gauhati University for their necessary support.

Abstract: A new variety, Chara corallina var. kamrupensis P.P.Baruah, S.Bhattacharjee, N.Kalita & B.Boruah var. nov. is described from Kamrup District, Assam (India), based on the observations made under light and scanning electron microscope. This new variety differs from the other two taxonomically accepted varieties of the species viz., C. corallina var. kyusyensis K.Imahori and C. corallina var. portonovensis D.Subramanian in having bracts throughout the body, number of spirals in oogonia, and reduced size of antheridia & coronula cells.

Keywords: Chara corallina var. kamrupensis, Charophyta, freshwater habitats, green algae, light microscopy, scanning electron microscopy, stoneworts.

Charophyta, popularly known as stoneworts or brittleworts constitute one of the major groups of macrophytic green algae occurring in fresh to brackish water ecosystem (Mondal et al. 2021), which shows similarities with some aquatic angiosperms like, Ceratophyllum, and Myriophyllum (Casanova 2005; Baruah et al. 2024). A few unique morphological features such as, presence of nodes & internodes, branchlets, bracts, stipulodes, and attractive reproductive structures (Mann et al. 2022) like nucule (female reproductive structure), and globule (male reproductive structure) make the taxa different from the other algal groups (Mandal & Ray 2004).

As per algaebase (Guiry & Guiry 2023), a total of 360 taxonomically accepted taxa have been accounted under the genus Chara, which includes 221 species, three sub-species, 49 varieties, and 87 formae throughout the globe. The species Chara corallina Willdenow, 1805, is one of the most attractive species within the genus Chara that have unique characteristics like monoecious plant body, and gametangia at the base of the whorl. According to the recent literature, this species itself has been divided into two accepted varieties, viz., Chara corallina var. kyusyensis K. Imahori, 1954, and Chara corallina var. portonovensis Subramanian, 1981 (Guiry & Guiry 2023). The former was first reported from Japan by Imahori (1954) inhabiting freshwater habitat. Subsequently, the species was reported from Korea (Choi & Kim 1996), and India (Karande 1999). On the other hand, C. corallina var. portonovensis was reported for the first time by Subramanian (1981) from a freshwater habitat of Tamil Nadu (India) which was later on documented in a checklist by Gupta (2012)) from the same region.

The study of a few Chara corallina samples in different freshwater aquatic habitats from the Kamrup District of Assam during routine explorations revealed an interesting variety of the species. In this study, we introduce a new variety of Chara corallina Willdenow, 1805 with photomicrographs & descriptions, and compare it with the other two aforementioned varieties. The present communication is aimed to highlight light microscope (LM) and scanning electron microscopic (SEM) observations, and descriptions of Chara corallina var. kamrupensis, a new additional variety, to science from Kamrup District of Assam (India).

Materials and Method

Collection and observation of samples

Samples were collected from the different freshwater habitats of Kamrup (S1 – 26.087^O N, 91.610^O E; S2 – 25.975^O N, 91.235^O E; S3 – 26.449^O N, 91.622^O E; S4 – 26.348^O N, 91.729^O E) and Aquaculture & Biodiversity Centre (S5-26.154^ON, 91.666^OE) of Gauhati University under Kamrup Metro District of Assam (India). Physicochemical properties of the habitats like pH, temperature, and conductivity were also measured to be pH 6.8–7.6, 18–22 ^OC, and 139–260 µS/cm, respectively. After collection, samples were washed vigorously with double distilled water, and brought to the Plant Ecology Laboratory, Gauhati University for observations. Leica S9i microscope was used for photography of the samples in fresh conditions. Herbarium was also prepared after drying and fixing the part of the collected samples in Formalin-Glacial Acetic Acid-Alcohol (FAA) solution following the standard protocol as given by Seshagirirao et al. (2016), and the remaining portion of the samples were preserved in 4% formalin solution following Mondal et al. (2021) for future use.

FeSEM study

A portion of the fresh samples was first washed in double distilled water followed by detachment of reproductive parts using scalpels and needles, air dried at room temperature by keeping them on a glass cover slip. Once dried, the samples were dipped in 3% glutaraldehyde solution for 24 h in 4^OC and then 0.1 M phosphate buffer was used to rewash the sample. The samples were dehydrated with 30%, 50%, 70%, 90%, 100% ethanol solution (Sadiq et al. 2017), and then coated with gold as per protocol prior to taking SEM photographs (John & Moore 1987; Urbaniak 2011) with SEM-Zeiss Sigma 300 at CIF, Gauhati University.

Identification of the sample

The samples were identified morphologically by comparing the characters with the standard monographs and literature, i.e., Sundaralingam (1959), Pal et al. (1962), Wood & Imahori (1964), Choi & Kim (1996), Subramanian (2002), and John et al. (2005).

Results

Taxonomic treatment

Chara corallina var. kamrupensis P.P.Baruah, S.Bhattacharjee, N.Kalita & B.Boruah, var. nov. (Figure 1–4)

Plant monoecious, more than 40 cm in height (Image 1A); axis stout to fragile, 350–450 µm in diameter; ecorticated; Branchlet 2–3 times longer than internodes, six in a whorl (Image 1D), each with 3–4 segments, ultimate segment smaller and conical to oval in shape having only one dactyl (Image 1C); branchlets swollen at node/nodal region; both upper and lower nodes possess bracts, bracteoles absent throughout the body; stipulodes rudimentary; Gametangia produced at the base of the whorls as well as at the nodes, aggregated at the base (Images 1D,E), and solitary at node (Image 1I); antheridia mature earlier than oogonia; Antheridia smaller than the typical varieties, 367–407 µm in diameter (Image 4C) , greenish in colour (Images 1E,F,H,I) ; Oogonium small, 940–1,000 µm in length with coronula cell, 700–750 µm broad (Image 4A), greenish in colour but gradually turns into brick-red at maturity; Coronula five in number, 40–47 µm long, 25–30 µm broad (Image 1G; Image 4B); spiral cells five in number with eight convolutions.

Present specimen tallies with C. corallina var. portonovensis (Subramanian 2002) but differs in:

1. Presence of bract throughout the body.

2. Much smaller antheridia and oogonia.

3. Number of spirals in oogonia.

4. Much smaller coronula cells.

Present specimen tallies with C. corallina var. kyusyensis (Choi & Kim 1996) but differs in

1. Presence of bract throughout the body.

2. Lower node sterile.

3. Smaller antheridia and larger oogonia.

4. Much smaller coronula cells.

Type: India, Assam: Kamrup District, Aquaculture and Biodiversity Centre, 26.154O N & 91.666O E, 72 m, 5.xi.2023, S. Bhattacharjee GUBH20650 (holotype: GUBH) (Image 5)

Etymology: The variety ‘kamrupensis’ is named after its collection site Kamrup District.

Discussion

Chara corallina, a notable morphologically attractive as well as ecologically well-known freshwater species within the genus Chara that mainly has two taxonomically accepted varieties, viz., C. corallina var. portonovensis and C. corallina var. kyusyensis. The present endeavour provides the unique diagnostic differences (Table 1) of the studied species from these accepted varieties due to the presence of sterile lower nodes and bracts, a critical morphological distinguishing feature (Pal et al. 1962). The absence of bracts in C. corallina var. portonovensis (Subramanian, 2002) and rudimentary or sometimes absent (Choi & Kim 1996) in C. corallina var. kyusyensis could make us convinced to differentiate this variety form the other two. The studied species closely resembles C. corallina var. portonovensis in branchlet morphology but differs from C. corallina var. kyusyensis due to its lower sterile branchlets (Choi & Kim 1996; Subramanian 2002). The studied variety possesses a bunch of extremely smaller antheridia of having a size of less than 500 µm also established this study taxon as a new variety (Table 2). Though there have been insufficient SEM investigations to distinguish between the varieties of C. corallina, an effort was made to observe the gametangia sizes that underscore with facts and figures as an authenticated novel variety. 

Table 1. Comparison between the vegetative features of accepted varieties of Chara corallina with the new variety.

Features	C. corallina var. portonovensis D. Subramanian (Subramanian 2002)	C. corallina var. kyusyensis K.Imahori (Choi & Kim 1996)	C. corallina var. kamrupensis var. nov.
Plant body	Monoecious, lower node sterile	Monoecious, lower node fertile	Monoecious, lower node sterile
Height	Up to 23 cm	Up to 30 cm	Up to 40 cm
Thickness	4,000 µ	1,000 µ	450–650 µ
Stipulodes	ND	Degenerated	Rudimentary
Bracts	Absent at the upper node	Rudimentary or absent or degenerated	Present (3 in a whorl), throughout the body (Images 1B, 2A,B,C)
Branchlets	Six branchlets in a whorl with 5–6 segments	Six branchlets in a whorl with five segments	Six branchlets in a whorl with 3–4 segments (Images 1A, 2A,B)

Table 2. Comparison of reproductive structure of accepted varieties of Chara corallina with the new variety.

Characteristics	C. corallina var. portonovensis D.Subramanian (Subramanian 2002)	C. corallina var. kyusyensis K. Imahori (Choi & Kim 1996)	C. corallina var. kamrupensis (Studied Species)
Oogonia	Large, orange, 2,500–2,600 µm in length; 1,200–1,300 µm in breadth.	700 µm in length; 450 µm in breadth.	Moderate, Greenish, 940–1,000 µm in length; 700–750 µm in breadth. (Images 1E,F,G, 4A,B)
Antheridia	Very large, orange, 1,335 µm in diameter	480–640 µm in diameter	Very small, Brick reddish, 367–407 µm in diameter (Images 1E,F,H,I, 3A,B,C, 4C)
Coronula	235 µm long, 200 µm broad	120 µm long, 270 µm broad	40–47 µm long, 25–30 µm broad (Images 1G, 4B)

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