Introduction
Psammogeton Edgew. (Apiaceae) is a tiny genus that is mostly limited to Asia and has a natural range that extends from Iran, Iraq, and central Asia (Govaerts et al. 2021). As a traditionally circumscribed the monophyly of Psammogeton is yet to be confirmed (Mousavi et al. 2022). In India, the native range of Psammogetonspecies is lowlands of the Jammu of Jammu and Kashmir (Fig. 1). Almost all the species of Psammogeton are adapted to dry rocky, stony, sandy situations particularly margins of river beds. On the basis of morphological and phylogenetic affinities Psammogeton is closely related to its allied genus Aphanopleura . Psammogeton anethifolium , P. biternatum , P. canescens , P. diffusus , P. involucratum and P. shivalikense are the species that constitute the genus in India. Psammogeton biternatum , P. canescens , P. shivalikense and P. suchaniense have all been identified in Jammu & Kashmir so far. According to Boissier (1872), Clarke (1879), Drude (1998), Hiroe and Constance (1958), Kitamura (1960), Heywood and Dakshini (1971), Nasir (1972), Babu (1977) Ahmed and Koul (1979), Hamal and Koul (1980), Sharma and Kachroo (1981), Hedge et al. (1987), Rechinger (1987), Mukherjee and Constance (1993), Katz-Downie (1999), Downie et al.(2000, 2010), Pimenov and Leonov (1993, 2004), Mohanan and Pimenov (2007), Assadi et al. (2008), Ajani and Mozaffarian (2019), Pimenov et al. (2019), a review of the taxonomic literature revealed that the species has not yet been named. By examining taxonomic literature, the correctness of the species and description has been verified. Further confirmation was also acquired by consulting herbarium specimens housed in different national and international herbaria throughout the world. By comparing these specimens and reviewing relevant literature, including Hiore and Constace (1958), Heywood and Dakshini (1971), Babu (1977), Sharma and Kachroo (1981), Mukherjee and Constance (1993), Pimenov and Leonov 2004), it was determined that the species had not yet been reported. This may be due to the species’ small size, patchy distribution in highly disturbed dry riverbank areas, and proximity to international borders where there are restrictions on free movement. The Tawi River bank west of Jammu, close to Mandal, is the place where authors found several unique sample specimens. During the field inquiry between 2018 and 2022, the location is quite near the Pakistani border. Based on these factors, as well as comparative morphology and anatomical study, the authors were able to identify and describe it as a new species.
The root, petiole, stem, and fruit of Apiaceae species exhibit sectetory chambers (vittae) that may contain schizogenic fatty channels carrying region, oil, or mucilage (Duman et al. 2000, Metcalfe and Chalk 1950). Nevertheless, anatomical traits are not employed as morphological traits in the Apiaceae family to differentiate between closely related species and genera. (Urusak and Kizilarslan 2013). The size of the pericarp, thickness, exocarp cell size, vittae, and the investigations revealed several diagnostically significant characteristics of the fruit and its velluculae in addition to a broad range of diversity in fruit morphology and morpho-anatomical parameters among the analysed taxa. The research under inquiry expands our understanding of stem and fruit morphology. These data had little taxonomic relevance because the quantitative values frequently overlapped. Micro-morphological characteristics, fruit surface characteristics, and fruit architecture therefore seem to be more useful for identifying species. In Apiaceae, the quantity and configuration of vallecular and comissural vittae inside the pericarp frequently play a significant role. Although this characteristic differs among several species in this family, the size of the vittae appears to be more informative. In addition, an identification key has been prepared to represent the similarities and differences between the closely related species of Apiaceae.