ASSESSMENT OF ANGIOSPERMIC FLORA AT RAJSHAHI METROPOLITAN AREA OF BANGLADESH

Objectives: The study aimed to document the angiospermic flora at Rajshahi metropolitan area of Bangladesh. The study also examined the species diversity in the study area. Methods: The research work is based on fresh materials collected during 33 field visits at Rajshahi metropolitan area of Bangladesh was carried out from February 2016 to March 2017 to cover the seasonal variations. Plant parts with either flower or fruits collected using traditional herbarium techniques to make voucher specimens for documentation. Results: The results show that a total of 494 species belonging to 455 genera and 106 families were recorded. Of these, Magnoliopsida (Dicotyledones) is represented by 413 species under 390 genera and 84 families while Liliopsida (Monocotyledones) is represented by 81 species under 65 genera and 22 families. For each species scientific name, local name, family name, habit, relative occurrence, and flowering time were recorded. The present study will help in identifying the major angiospermic plant species for further investigation. Conclusion: The present research focused on the angiospermic flora growing throughout the Rajshahi metropolitan area of Bangladesh. A total of 494 angiospermic plant species were recorded.


INTRODUCTION
Flowering plants (angiosperms) are the most diverse group of land plants, also known as Angiospermae Lindl or Magnoliophyta. Angiosperms, like gymnosperms, are seed-producing plants that can be distinguished from gymnosperms by a series of synapomorphies (derived characteristics). Flowers, endosperm within the seeds, and the production of seeds-containing fruits are among these characteristics. Angiosperm is an etymological term for a plant that produces seeds within a container; they are fruiting plants, though they are more commonly known as flowering plants.
A taxon's description, whether it is a phylum, a family, or a species, is a declaration of its traits, which together form the taxon's definition. Taxonomic or systematic characters are those that contribute to a taxonomic description. A diagnosis is a condensed description that only includes the diagnostic features that are required to distinguish a taxon from other taxa. For example, the genus Brassica has various species such as Brassica nigra (black mustard), Brassica juncea (rai), Brassica rapa (shalgam), and others; however, the genus Brassica is distinguished from all other genera in the Cruciferae family by some common characteristics (Brassicaceae). Angiosperms are vascular plants that produce seeds. Flowers with ovules enclosed in an ovary are their reproductive structures. Angiosperms can be found in a wide variety of environments, from forests and grasslands to seashores and deserts. Trees, herbs, submerged aquatics, bulbs, and epiphytes are just a few of the life forms found in angiosperms. Orchids, Compositae (daisies), and legumes are the three largest plant families (beans). Flowering plants, also known as angiosperms has number around 3, 52, ooo species of the world. Around 245-202 million years ago, flowering plants split from gymnosperms and the first flowering plants were discovered around 160 million years ago. During the Lower Cretaceous, they diversified greatly and became widespread around 120 million years ago, but they only replaced conifers as the dominant trees around 60-100 million years ago [1].
Angiospermic flora was carried out in Bangladesh by . The aim of the present research was to explore and assess the diversity of angiosperms at Rajshahi metropolitan area of Bangladesh.

DISCUSSION
Based on this study, a preliminary list of angiosperm diversity at Rajshahi metropolitan area of Bangladesh conducted during February 2016-March 2017. A total of 494 species belonging to 455 genera under 106 families were recorded. The collected information is comparable with the result of other studies in Bangladesh. A total of 243 species belonging to 195 genera under 95 families were recorded in Khagrachhari district [5]. A total of 374 species belonging to 264 genera under 84 families were recorded in Lawachara National Park [33]. A total of 153 species belonging to 120 genera under 52 families were recorded in Runctia Sal Forest [30]. A total of 245 species belonged to 183 genera and 72 families are documented in Habiganj district [49]. A total of 425 species belonging to 321 genera 108 families are recorded in Rajshahi district [18]. A total of 302 species belonging to 243 genera 84 families are recorded in Bangladesh Police Academy, Rajshahi [23]. No detail previous information recorded on the diversity of angiospermic flora at Rajshahi metropolitan area of Bangladesh.

CONCLUSION
The present research focused on the angiospermic flora growing throughout the Rajshahi metropolitan area of Bangladesh. A total of 494 species belonging to 455 genera and 106 families were recorded. Observations and group discussions with local people during field visits noted that urbanization, lack of awareness, and invasive plant species were the major threats in declining the explore of angiospermic plants. Therefore, efforts should be undertaken through ex situ and in situ conservation approaches, public awareness, and habitats protection to ensure for increase diversity of angiospermic plants.

ETHICAL APPROVAL
Angiospermic flora from Rajshahi metropolitan area of Bangldesh was observed in this study. The ethical guidelines for plants and plant materials are followed in the study for sample collection and identification.

INFORMED CONSENT
Not applicable.

DATA AND MATERIAL AVAILABILITY
All data associated with this study are present in the paper.

ACKNOWLEDGMENTS
The authors are grateful to the local people at Rajshahi metropolitan area, Bangladesh, for their cooperation and help during the research work.