Browsing by Author "Santosh Kumar Shukla"

Now showing 1 - 8 of 8

A new subspecies of Isoetes coromandelina (Isoetaceae) from Gujarat, India
(College of Life Science, 2017) Santosh Kumar Shukla; Sarvesh Kumar Singh; Pradeep Kumar Shukla; Nawal Kishor Dubey; Husnara Khanam; Gopal Krishna Srivastava
In the present study Isoetes coromandelina ssp. thanensis S.K. Shukla, S.K. Singh, P.K. Shukla, N.K. Dubey, H. Khanam & G.K. Srivastava a micro endemic new subspecies is described from the Than in Rajkot District of Gujarat state in coastal zone of India. Morphologically, the new subspecies is most similar to I. coromandelina ssp. coromandelina but differs in its microspore with levigate surface ornamentation and chromosome number 2n = 22 + 1. Different morphological features of I. coromandelina ssp. thanensis are discussed. Images and a distributional map are also provided. In the present study, we made a correlation between microspore ornamentation and ploidal status at the infra-specific level which helpful in taxonomy of closely related taxa. © 2017, College of Life Science. All rights reserved.
Hydrochemical characterization of some stands of Isoetes Dixitei in India
(College of Life Science, 2015) Brij Bhan Yadav; Sarvesh Kumar Singh; Nawal Kishor Dubey; Santosh Kumar Shukla; Gopal Krishna Srivastava
In the present study soil, water and plant samples were collected from seven different natural populations of Isoetes dixitei which are found growing on the tablelands of Satara and Kolhapur districts of Maharashtra, India. The collected soil and water samples have been analysed for the colour, texture, available plant nutrients, electrical conductivity, pH and BOD. The soil and water factors along with biotic factors are compared with the number of plants per m2, length of plants, number of leaves and roots per plant to understand the morphological diversity and biology within different populations of I. dixitei. The results of present analysis reveals that these ecological factors such as organic carbon, iron, phosphorus and potassium in soil and low pH of soil and water have positive relationships with the growth, robustness and diversity of I. dixitei. However, copper, zinc and electrical conductivity in the soil have negative significant role in influencing the plant characters. The role of manganese appears to be not significant. The biological factors play major role in controlling the diversity (number of plants per m2) of this taxon. © 2015 College of Life Science. All rights reserved.
Isoetes bilaspurensis (Isoetaceae – Lycopodiopsida), New to Southern India: An Extended Distribution and Redescription
(American Fern Society, 2024) Pradeep Kumar Shukla; Sarvesh Kumar Singh; Daniel F. Brunton; Santosh Kumar Shukla; Anant Prakash Patil; Nawal Kishor Dubey
The authors discovered a previously unknown population of Isoetes at Badami in Bagalkot district of Karnataka state, India in October 2022 which is determined to be I. bilaspurensis. This represents a new record for the Deccan plateau of Southern India and a significant disjunction from its previously known distribution in Chhattisgarh and Madhya Pradesh, Central India. In light of this additional information a revised, detailed description of I. bilaspurensis is presented. Morphological comparisons with closely related taxa, its conservation status, and the phytogeographic implications of its distribution are also provided. © 2024 American Fern Society. All rights reserved.
Isoetes ×gopalkrishnae (Isoetaceae), a new interspecific sterile hybrid from Central India
(Magnolia Press, 2018) Sarvesh Kumar Singh; Santosh Kumar Shukla; Nawal Kishore Dubey; Pradeep Kumar Shukla
Isoetes ×gopalkrishnae hybr. nov., is described, illustrated and compared with possible parent species. Based on morphological characteristics and habitat conditions, this taxon is considered to represent a sterile hybrid between I. coromandelina and I. panchananii. The new hybrid is amphibious and grows on the exposed shore of an artificial pond. It is known only from a single locality on the Vindhya plateau in Uttar Pradesh, India. It can be distinguished from other taxa by a combination of characters including the lack of a scale, the leaf which is terete in transverse section, velum absent to rudimentary, a sporangial wall with internal pigmentation, rugulate megaspores with a smooth equatorial girdle and microspores with densely echinate to short-cristate ornamentation. It is the first Isoetes hybrid reported from the Indian subcontinent. © 2018 Magnolia Press.
Morphological studies of the ligules of selected Indian species of Selaginella (Selaginellaceae)
(Elsevier GmbH, 2019) Sarvesh Kumar Singh; Santosh Kumar Shukla; Nawal Kishore Dubey; Pradeep Kumar Shukla; Richard V. Lansdown
The article presents the results of a study of the ligule morphology of both vegetative and reproductive leaves of four species of Selaginella, i.e. S. delicatula, S. ganguliana, S. plana and S. tenera, occurring in India. Ligules of S. ganguliana, S. plana and S. tenera are described for the first time, and the occurrence of shuttlecock-like ligules is described for the first time. Ligule shape is generally constant across the species studied but some minor morphological variations are observed within species. However, in combination with other morphological characters, the ligule may be a useful tool in the taxonomic delimitation of closely related Selaginella species. In addition, we propose that ligule size may be influenced by the habitat conditions, whereas the presence of glandular cells at their tip margins possibly indicate a water secreting function. © 2019 Elsevier GmbH
Rediscovery of presumed extinct Isoetes divyadarshanii (Isoetaceae—Lycopodiopsida) in India: New insight on its morphology, taxonomy and conservation status
(Magnolia Press, 2025) Sarvesh Kumar Singh; Daniel Francis Brunton; Pradeep Kumar Shukla; Paul Clayton Sokoloff; Santosh Kumar Shukla; Anant Prakash Patil; N. K. Dubey
A population of Isoetes divyadarshanii, a species previously known only from its type location in Maharashtra State, India and considered extinct since at least 2013, was discovered on the Sada Plateau in the Belagavi District of Karnataka state, India in October 2023. This represents a significant disjunction (over 465 km) from its type location into a different phytogeographic division of the Indian subcontinent. The new information provided by this discovery permits verification of critical elements of the original description. It also allows for an updated and more precise description of the morphology, ecology and taxonomy of this poorly understood taxon. A detailed morphological comparison with closely related taxa, especially I. udupiensis, is presented. The cytology of the new population is reported (2n = 2× = 22) and the IUCN conservation status criteria designation of the species is revised from Critically Endangered (Extinct) to Endangered. Finally, the phytogeographic implications of this new discovery are discussed. © © 2025 Magnolia Press.
The significance of a new umbellate ornamentation in Isoetes (Isoetaceae: Lycopodiopsida) megaspores
(Taylor and Francis A.S., 2021) Sarvesh Kumar Singh; Pradeep Kumar Shukla; Nawal Kishore Dubey; Santosh Kumar Shukla
A new umbellate ornamentation pattern is described in Isoetes megaspores based on scanning electron microscopy and thorough comparisons with sculptural patterns documented in lycophytes and ferns. The umbellate ornamentation is quite distinct from other vertically projected megaspore sculptural patterns (baculate, clavate, gemmulate, pustulate, tuberculate, saccate and verrucate). In addition, megaspore ornamentations described previously for I. dixitei as tuberculate or pustulate have now been corrected as umbellate. This species also possesses a rudimentary velum and internal pigmentation in sporangial wall which has not been reported in other Indian species of the genus. Further, this taxa has a range restricted to the Western Ghats and is confined to a higher elevational range than Indian species characterised by vertically projected megaspore surface ornamentation patterns. © 2020 Collegium Palynologicum Scandinavicum.
The taxonomy and conservation status of Isoetes (Isoetaceae; Lycopodiopsida) in India
(Taylor and Francis Ltd., 2021) Sarvesh Kumar Singh; Pradeep Kumar Shukla; Daniel F. Brunton; Nawal Kishore Dubey; Santosh Kumar Shukla
In many cases over the years the diversity of Isoetes in India has been defined by inconsistent morphological analyses and questionable data. This has resulted in substantial confusion, dramatically different taxonomic interpretations and a low level of global acceptance. That in turn has prevented the reliable determination of conservation priorities. The present study reviews the most reliable morphological, distributional and cytological Indian data available with techniques and standards that have guided successful taxonomic investigations of Isoetes elsewhere in the world. This results in the enumeration of nine readily distinguishable species for India. One named hybrid is also discussed as is the probable occurrence of other unnamed hybrids. All Indian Isoetes species except I. coromandelina subsp. coromandelina are endemic. Two possible but unresolved taxa are also discussed. A clearer determination of the highest national priorities for Isoetes conservation has resulted. Most Indian taxa are rare, some qualifying as Endangered and others probably being extinct. Suggestions for conservation strategies and actions to protect and sustain vulnerable Isoetes species and their habitats are offered. © 2020 Société botanique de France.