REVIEW OF SIMPLIFIED TECHNIQUES FOR TAXONOMIC STUDIES OF PLANTS (original) (raw)
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Botanical classification and nomenclature - an introduction
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Biology is the science that explores the living world around us. To communicate the wonders of nature, names are needed to describe the variety of forms we encounter. This wildly diverse nature may be represented through a hierarchical structure where names are used to indicate groups of organisms at different levels. The classification and naming of organisms is an essential tool for scientific communication. It forms the foundation upon which biological research is based and the discipline is called "<strong>Taxonomy</strong>". Taxonomists explore, describe, name, and classify all living organisms on Earth. Correctly classifying and naming organisms is crucial to a wide range of biological research fields. Such a framework is also essential to address the topics of sustainable usage and biodiversity management and conservation, including their legal context. This booklet provides an overview of the most important elements and processes of the classification a...
Cebu Normal University, 2019
Kingdom plantae serves a variety of functions in the natural world, including recycling of nutrients, in the food chain, and provides oxygen to other organisms. On top of that, most of the world’s ecosystems have plant diversity. In tropical countries like the Philippines, this diversity is higher compared to other regions. It’s often not easy to find the name of a particular plant by just looking in a reference book, viewing photographs or reading a description. But when you see the actual specimen and use a magnifying glass or microscope to check the plant’s size or observe its characteristics you will then be able to make an identification. Humans have different faces and other physically distinguishing characteristics. Plants of the same species also differ in characteristics depending on the habitat and the individual plant. By looking at archived specimens in a herbarium, we can see the morphological variances without having to visit the habitat where the plant was collected. If a plant specimen is correctly collected and stored, a DNA sample can be extracted and analyzed to determine the plant’s genealogy and derivation. All specimens made properly by anyone for any purpose have an academic value.
Numerical and comparative analyses of the modern systems of classification of the flowering plants
Botanical Review, 1998
The modern classifications of Cronquist, Dahlgren, Takhtajan, and Thorne have been compared with one another and also with those published at the beginning of the 20th century, which comprise the ones by Bessey, Engler, Gobi, and Hallier. Mantel and consensus tests have been used to compare the different matrices taken from the above classifications. Results indicate that all four modern classifications do not differ from one another statistically. Ordinal delimitation has not changed significantly for a century at least: Orders of the modern classifications are similar to those of the past classifications. However, the topology or structure of Cronquist’s and Takhtajan’s classifications differs from that of Bessey’s. Also, Engler’s dicotyledon classification is statistically different from those of the modern systems. Among past classifications, that of Hallier resembles the modern ones most. The resemblance among the modern classifications and, in general, with the past ones can be explained by the similarity in taxonomic principles and in the practice used. Two other factors help in explaining similarities among classifications: cognitive constraint and historical inertia. For instance, the Linnean scheme—upon which all botanical classifications are based—imposes on the latter a structure which allows only with difficulty and approximation the representation of taxon evolution. Moreover, not only have modern authors mutually influenced one another (particularly Cronquist/Takhtajan, Dahlgren/Thorne), but also they have been influenced by past authors. Indeed, modern classifications are a reshuffling of past ones. Also, Engler’s influence is great, especially at the ordinal level. For changes and modifications to become effective in future classifications of flowering plants, one will have to minimize, if not avoid, the implicit influence of the modern systems as standard systems, and to count on, among others, molecular data in redefining taxonomic concepts founded on classical morphology, and consequently to remove the prudence that makes us look at classification as a useful convention for which one of the basic criteria remains the stability of taxa recognized long ago. Les classifications modernes de Cronquist, Dahlgren, Takhtajan et Thorne sont comparées entre elles et avec les principales classifications du début du XXe siècle, celles de Bessey, Engler, Gobi et Hallier. Les tests de Mantel et de consensus ont été utilisés pour permettre la comparaison des différentes matrices tirées des classifications mentionnées ci-dessus. Les résultats des comparaisons montrent que les quatre classifications modernes ne diffèrent pas statistiquement entre elles. La délimitation des ordres n’a pas changé de façon significative depuis au moins un siècle: les ordres des modernes sont semblables à ceux des anciens. Toutefois, la topologie des classifications de Cronquist et de Takhtajan s’éloigne de celle de Bessey. La classification des Dicotylédones d’Engler diffère de celles des modernes. Parmi les classifications anciennes, celle de Hallier ressemble le plus aux modernes. La grande ressemblance des modernes entre eux et avec les anciens s’explique par la similarité dans les principes et l’approche taxonomique utilisés. Deux autres facteurs expliquent cette similarité: la contrainte cognitive et l’inertie historique. D’une part, la structure linnéenne qui fonde les classifications botaniques actuelles, impose aux classifications une rigidité qui permet difficilement la représentation de l’évolution des taxons. D’autre part, non seulement les auteurs modernes se sontils mutuellement influencés (surtout Cronquist/Takhtajan, Dahlgren/Thorne), mais ils ont été influencés par les anciens. Les classifications modernes sont en fait un remaniement des anciennes. De plus, l’influence d’Engler est forte, surtout au niveau de la délimitation des ordres. Les prochaines classifications des plantes à fleurs devront—pour que les changements se fassent sans contrainte — éviter l’influence implicite des systèmes modernes en tant que système-étalon, miser, entre autres, sur les données moléculaires pour redéfinir les concepts taxonomiques fondés sur la morphologie traditionnelle, et lever la prudence qui fait que l’on conçoit la classification comme une convention utile pour laquelle l’un des critères de base est la stabilité des taxons reconnus historiquement.
LEAF ARCHITECTURE AS A PROMISING TOOL IN CONFIRMING IDENTITY OF CONFUSING PLANT TAXA
The search for stable taxonomic characters has always been a subject of interest among taxonomists and systematists. Several studies had been using tools such as gross morphology, anatomy, biochemistry and molecular biology to address or somehow resolve taxonomic problems. However, these studies were limited, depending on the resources made available to a laboratory or office. This paper presents leaf architecture as another potential tool in taxonomy. Leaf architecture refers to patterns of venation in leaves, found to be genetically fixed. Published literature in selected journals were reviewed in detail and were synthesized. The review indicated that leaf architecture is currently used in 1) species identification, 2) species description, and 3) species classification. It has been quite effective in addressing nomenclatural issues between two morphologically similar species, very common in many cultivated plants, like Hoya, causing taxonomic confusion among gardeners, hobbyists and even taxonomists. Gaps include, 1) small number of specimens or small number of representative species (for family and generic studies), though leaf samples taken, were at least 30 per species, 2) samples were taken from a single source most of the times, disregarding possible variation when samples are from diverse localities, topographies, elevations and agroclimatic conditions, and 3) age of the leaf was not a consideration in collecting samples. Despite these gaps, though, leaf architecture has a very high potential to complement reproductive structure-based Linnean taxonomy and the modern day molecular taxonomy.
Ongoing floras and modern classifications: How to organize our families?
Plant classifications from the end of the 19th century to the end of the 20th century were based upon the analysis of characters to produce an intuitive evolutionary hypothesis through a phenetic approach. The first of these classifications is that of Bentham and Hooker (1862-1883), followed by Engler’s Syllabus (Melchior & Werdermann, 1954-1964), and Cronquist’s classification (1968, 1981, 1988). Cronquist’s classification has been the primary reference until the beginning of the 21st century. Ongoing monographic series (e.g., Flora Neotropica), textbooks, and floristic treatments referred, and many still refer, to this classification as the standard reference (e.g., Heywood, 1993; Mabberley, 1997; Smith, 2004). Takhtajan’s classifications (1968, 1988, 1997, 2009), were often presented side by side with those of Cronquist, and were similar in many aspects, mostly by recognizing two classes of flowering plants, Magnoliopsida (dicotyledons) and Liliopsida (monocotyledons). The main i...
Floristic and Biosystematic Investigations in Plant Taxonomy
1997
Characters 1. Height of Plants 2. Nodes-glands 3. Nodes-indurnentum 4. Intemodes-glands 5. lntemodes-indurnentum 6. Sheaths-glands 7. Sheath Margins-indumentum 8. Blade Surfaces, Adaxial-glands 9. Blade Surfaces, Abaxial-glands 10. Blade Margins-glands 11. Blade Bases-indumentum 12. Inflorescences-width 13. Peduncles-glands 14. Peduncles-indurnentum 15. Central Axes-glands 16. Central Axes-abundance of glands 17. Central Axes-indumentum 18. Pedicels-glands 19. Pedicels-abundance of glands 20. Pedicels-indumentum 21. Florets-length of first floret 22. Calluses-indumentum 23. Glumes-length relative to each other 24. Glumes-length relative to florets 25. Lower Glurnes-awns 26. Lower Glumes-length of awns 27. Lower Glumes-glands of awns 28. Lower Glumes-length 29. Lower Glumes-width 30. Lower Glumes-glands 31. Upper Glumes-awns 32. Upper Glumes-length of awns 33. Upper Glumes-glands 34. Upper Glumes-length 35. Upper Glumes-width 36. Upper Glumes-glands 1. Glands absent on culms and leaves.
Journal of Plant Sciences (Science Publishing Group), 2015
The morphological description of some selected tropical plants in Ogun State, Nigeria was investigated. This is with a view to bridge existing more or less compartmentalized foliar descriptions which are discrete and lack the observed continuum of shape types in nature. Plants from which leaves were collected and observed for the different traits were randomly collected from some Local Government Areas of the State. The qualitative macromorphological characters observed include, leaf type, leaf shape, leaf apex, leaf base and leaf margin with varying percentage occurrence. Of the 74 distinct foliage types examined 62(84%) matched the existing foliage descriptions in literature while 12(16%) had undefined shape descriptions. It was observed that simple (79%), ovate and lanceolate (18%), entire (58%), acute (26%), acute (44%) had the highest frequency for the leaf type, leaf shape, leaf margin, leaf apex and leaf bases respectively, while the lowest frequency was recorded to be compound (21%), linear, oblanceolate, acicular, orbicular, sagitate, falcate, peltate, hastate, lobed (1.6%), spinose, denticulate, crenate, parted (1.6%), mucronulate and cirrhose (1.6%), auriculate and hastate (1.6%) in the leaf type, leaf shape, leaf margin, leaf apex and leaf bases respectively. Other shapes hitherto undefined include: lanceospatulate, zygomorphic-trilobe, ensiformis, lobed-pentate, lobed-starlate and ellipto-dentoid. The study revealed that there is a continuum in plant foliage macromorphological description rather than independent occurrence of plant foliage characters found in literature.
Plant species delimitation: A comparison of morphological and molecular markers
Plant Biosystems, 2009
Species delimitation is fundamental in many areas of biology. Despite its importance, there is no agreement on criteria for species delimitation mostly due to divergence on the point of view adopted by the different biological disciplines. Two main groups of diagnostic characters are commonly used to distinguish species: the traditional morphological ones and the molecular ones. Field species recognition and sampling are generally based on morphological characters, but they can either fail to discriminate species and mask the presence of cryptic species or discriminate different species while in reality there is only one. To overcome this problem it is common to compare clusters obtained on the basis of the observed polymorphism of both characters, and to analyse their agreement. Here we compile a set of studies that have examined species delimitation with both markers. This provides a review of the different morphological and molecular markers, and of the sampling strategy and clustering methodology generally employed to delimitate species. Some conclusions are drawn with regard to species delimitation, when comparing diagnostic morphological and molecular markers.