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64-585: See text Podocarpaceae is a large family of mainly Southern Hemisphere conifers , known in English as podocarps , comprising about 156 species of evergreen trees and shrubs. It contains 19 genera if Phyllocladus is included and Manoao and Sundacarpus are recognized. The family achieved its maximum diversity in the Cenozoic , making the Podocarpaceae family one of the most diverse in

128-554: A lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching a consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called

192-515: A new branch the leaves may vary in a consistent pattern along the branch. The form of leaves produced near the base of the branch will differ from leaves produced at the tip of the plant, and this difference is consistent from branch to branch on a given plant and in a given species. This difference persists after the leaves at both ends of the branch have matured, and is not the result of some leaves being younger than others. The way in which new structures mature as they are produced may be affected by

256-425: A plant are emergent properties which are more than the sum of the individual parts. "The assembly of these tissues and functions into an integrated multicellular organism yields not only the characteristics of the separate parts and processes but also quite a new set of characteristics which would not have been predictable on the basis of examination of the separate parts." In other words, knowing everything about

320-579: A single individual, parts are repeated which may differ in form and structure from other similar parts. This variation is most easily seen in the leaves of a plant, though other organs such as stems and flowers may show similar variation. There are three primary causes of this variation: positional effects, environmental effects, and juvenility. Transcription factors and transcriptional regulatory networks play key roles in plant morphogenesis and their evolution. During plant landing, many novel transcription factor families emerged and are preferentially wired into

384-920: A stem grow longer and faster than cells on the other side, the stem will bend to the side of the slower growing cells as a result. This directional growth can occur via a plant's response to a particular stimulus, such as light ( phototropism ), gravity ( gravitropism ), water, ( hydrotropism ), and physical contact ( thigmotropism ). Plant growth and development are mediated by specific plant hormones and plant growth regulators (PGRs) (Ross et al. 1983). Endogenous hormone levels are influenced by plant age, cold hardiness, dormancy, and other metabolic conditions; photoperiod, drought, temperature, and other external environmental conditions; and exogenous sources of PGRs, e.g., externally applied and of rhizospheric origin. Plants exhibit natural variation in their form and structure. While all organisms vary from individual to individual, plants exhibit an additional type of variation. Within

448-414: A study of the development, form, and structure of plants, and, by implication, an attempt to interpret these on the basis of similarity of plan and origin". There are four major areas of investigation in plant morphology, and each overlaps with another field of the biological sciences. First of all, morphology is comparative , meaning that the morphologist examines structures in many different plants of

512-410: A unifying theme for the study of plant morphology. By contrast, the reproductive structures are varied, and are usually specific to a particular group of plants. Structures such as flowers and fruits are only found in the angiosperms ; sori are only found in ferns; and seed cones are only found in conifers and other gymnosperms . Reproductive characters are therefore regarded as more useful for

576-456: A very common network design tradeoff. Based on the environment and the species, the plant is selecting different ways to make tradeoffs for those particular environmental conditions." Honoring Agnes Arber, author of the partial-shoot theory of the leaf, Rutishauser and Isler called the continuum approach Fuzzy Arberian Morphology (FAM). “Fuzzy” refers to fuzzy logic , “Arberian” to Agnes Arber . Rutishauser and Isler emphasised that this approach

640-532: Is absorbed may be used by the plant to power chemical reactions, while the reflected wavelengths of light determine the color the pigment will appear to the eye. Plant development is the process by which structures originate and mature as a plant grows. It is a subject studies in plant anatomy and plant physiology as well as plant morphology. The process of development in plants is fundamentally different from that seen in vertebrate animals. When an animal embryo begins to develop, it will very early produce all of

704-449: Is an easy conclusion to make. The plant morphologist goes further, and discovers that the spines of cactus also share the same basic structure and development as leaves in other plants, and therefore cactus spines are homologous to leaves as well. This aspect of plant morphology overlaps with the study of plant evolution and paleobotany . Secondly, plant morphology observes both the vegetative ( somatic ) structures of plants, as well as

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768-445: Is an easy conclusion to make. The plant morphologist goes further, and discovers that the spines of cactus also share the same basic structure and development as leaves in other plants, and therefore cactus spines are homologous to leaves as well. When structures in different species are believed to exist and develop as a result of common adaptive responses to environmental pressure, those structures are termed convergent . For example,

832-499: Is commonly referred to as the "walnut family". The delineation of what constitutes a family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to

896-407: Is not only supported by many morphological data but also by evidence from molecular genetics. More recent evidence from molecular genetics provides further support for continuum morphology. James (2009) concluded that "it is now widely accepted that... radiality [characteristic of most stems] and dorsiventrality [characteristic of leaves] are but extremes of a continuous spectrum. In fact, it is simply

960-485: Is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family

1024-540: Is photosynthesis, which uses the green pigment chlorophyll along with several red and yellow pigments that help to capture as much light energy as possible the other pigments ic carotenoids'. Pigments are also an important factor in attracting insects to flowers to encourage pollination. Plant pigments include a variety of different kinds of molecule, including porphyrins , carotenoids , anthocyanins and betalains . All biological pigments selectively absorb certain wavelengths of light while reflecting others. The light that

1088-443: Is some disagreement about terminology. Rolf Sattler has revised fundamental concepts of comparative morphology such as the concept of homology. He emphasised that homology should also include partial homology and quantitative homology. This leads to a continuum morphology that demonstrates a continuum between the morphological categories of root, shoot, stem (caulome), leaf (phyllome), and hair (trichome). How intermediates between

1152-462: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Plant morphology Plant morphology "represents

1216-403: The reproductive structures. The vegetative structures of vascular plants includes the study of the shoot system, composed of stems and leaves, as well as the root system. The reproductive structures are more varied, and are usually specific to a particular group of plants, such as flowers and seeds, fern sori , and moss capsules. The detailed study of reproductive structures in plants led to

1280-612: The sister group to the Araucariaceae , and having diverged from it during the late Permian . While some fossils attributed to the family have been reported from the Late Permian and Triassic, like Rissikia , these cannot be unambiguously assigned to the family. The oldest unambiguous members of the family are known from the Jurassic period, found across both hemispheres, such as Scarburgia and Harrisiocarpus from

1344-765: The southern hemisphere . The family is a classic member of the Antarctic flora , with its main centres of diversity in Australasia , particularly New Caledonia , Tasmania , and New Zealand, and to a slightly lesser extent Malesia and South America (primarily in the Andes Mountains). Several genera extend north of the equator into Indochina and the Philippines . Podocarpus reaches as far north as southern Japan and southern China in Asia, and Mexico in

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1408-634: The African species fell under Podocarpus – P. falcatus , P. elongatus , P. henkelii , and P. latifolius . Taxonomists divided Podocarpus species into eight species groups based on leaf anatomy: Afrocarpus J.Buchholz & N.E.Gray, Dacrycarpus Endl., Eupodocarpus Endl., Microcarpus Pilg., Nageia ( Gaertn. ) Endl. , Polypodiopsis C.E.Bertrand (non Polypodiopsis Carriére nom. rej. prop. 6), Stachycarpus Endl. and Sundacarpus J.Buchholz and N.E.Gray . Studies of embryology, gametophyte development, female cone structure, and cytology led to

1472-531: The Americas, and Nageia into southern China and southern India. Two genera also occur in sub-Saharan Africa, the widespread Podocarpus and the endemic Afrocarpus . Parasitaxus usta is unique as the only known parasitic gymnosperm . It occurs on New Caledonia, where it is parasitic on another member of the Podocarpaceae, Falcatifolium taxoides . The genus Phyllocladus is sister to

1536-1309: The Middle Jurassic of England, as well as unnamed species from the Middle-Late Jurassic of Patagonia. Modern genera of the family first appeared during the Early Cretaceous, with the family probably reaching an apex of diversity during the early Cenozoic . Studies based on anatomical, biogeographical, morphological, and DNA evidence suggest these relationships: Saxegothaea Halocarpus Lepidothamnus Lagarostrobos Manoao Phyllocladus Prumnopitys Microcachrys Pherosphaera Acmopyle Dacrycarpus Falcatifolium Dacrydium Retrophyllum Nageia Afrocarpus Podocarpus Lepidothamnus Phyllocladus Halocarpus Parasitaxus Lagarostrobos Manoao Pectinopitys Sundacarpus Prumnopitys Saxegothaea Microcachrys Pherosphaera Acmopyle Dacrycarpus Falcatifolium Dacrydium Retrophyllum Afrocarpus Nageia Podocarpus Family (biology) Family ( Latin : familia , pl. : familiae )

1600-740: The Podocarpaceae sensu stricto . It is treated by some botanists in its own family, the Phyllocladaceae . The Podocarpaceae show great diversity, both morphologically and ecologically. Members occur mainly in the Southern Hemisphere, with most genetic variety taking place in New Caledonia, New Zealand, and Tasmania. Species diversity of Podocarpus is found mainly in South America and the Indonesian islands,

1664-464: The belief that the eight categories probably deserved generic status. Researchers agreed on the need to recognize "fairly natural groupings which prove to have good geographic and probably evolutionary cohesion" and took the necessary steps to raise each section to generic status. In 1990, a treatment of the Podocarpaceae recognized 17 genera, excluding Phyllocladus from the family, while recognizing Sundacarpus , but not Manoao . In 1995, Manoao

1728-444: The body parts that it will ever have in its life. When the animal is born (or hatches from its egg), it has all its body parts and from that point will only grow larger and more mature. By contrast, plants constantly produce new tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. The properties of organisation seen in

1792-429: The branches they will produce as a fully grown tree. In addition, leaves produced during early growth tend to be larger, thinner, and more irregular than leaves on the adult plant. Specimens of juvenile plants may look so completely different from adult plants of the same species that egg-laying insects do not recognise the plant as food for their young. Differences are seen in rootability and flowering and can be seen in

1856-495: The categories are best described has been discussed by Bruce K. Kirchoff et al. A recent study conducted by Stalk Institute extracted coordinates corresponding to each plant's base and leaves in 3D space. When plants on the graph were placed according to their actual nutrient travel distances and total branch lengths, the plants fell almost perfectly on the Pareto curve. "This means the way plants grow their architectures also optimises

1920-523: The classification of plants than vegetative characters. Plant biologists use morphological characters of plants which can be compared, measured, counted and described to assess the differences or similarities in plant taxa and use these characters for plant identification, classification and descriptions. When characters are used in descriptions or for identification they are called diagnostic or key characters which can be either qualitative and quantitative. Both kinds of characters can be very useful for

1984-502: The consequences for the plant depend very much on whether the freezing occurs intracellularly (within cells) or outside cells in intercellular (extracellular) spaces. Intracellular freezing usually kills the cell regardless of the hardiness of the plant and its tissues. Intracellular freezing seldom occurs in nature, but moderate rates of decrease in temperature, e.g., 1 °C to 6 °C/hour, cause intercellular ice to form, and this "extraorgan ice" may or may not be lethal, depending on

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2048-419: The discovery of the alternation of generations found in all plants and most algae. This area of plant morphology overlaps with the study of biodiversity and plant systematics . Thirdly, plant morphology studies plant structure at a range of scales. At the smallest scales are ultrastructure , the general structural features of cells visible only with the aid of an electron microscope , and cytology ,

2112-417: The environment to which the structures are exposed. A morphologist studies this process, the causes, and its result. This area of plant morphology overlaps with plant physiology and ecology . A plant morphologist makes comparisons between structures in many different plants of the same or different species. Making such comparisons between similar structures in different plants tackles the question of why

2176-540: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and

2240-441: The fronds of Bryopsis plumosa and stems of Asparagus setaceus both have the same feathery branching appearance, even though one is an alga and one is a flowering plant. The similarity in overall structure occurs independently as a result of convergence. The growth form of many cacti and species of Euphorbia is very similar, even though they belong to widely distant families. The similarity results from common solutions to

2304-420: The frost resistance of 1-year-old seedlings is on a par with mature plants, given similar states of dormancy. The organs and tissues produced by a young plant, such as a seedling, are often different from those that are produced by the same plant when it is older. This phenomenon is known as juvenility or heteroblasty . For example, young trees will produce longer, leaner branches that grow upwards more than

2368-478: The frost resistance of tissues, but the actual rate of freezing will depend not only on the cooling rate, but also on the degree of supercooling and the properties of the tissue. Sakai (1979a) demonstrated ice segregation in shoot primordia of Alaskan white and black spruces when cooled slowly to 30 °C to -40 °C. These freeze-dehydrated buds survived immersion in liquid nitrogen when slowly rewarmed. Floral primordia responded similarly. Extraorgan freezing in

2432-452: The fuzziness (continuity) of morphological concepts, the lack of a one-to-one correspondence between structural categories and gene expression, the notion of morphospace, the adaptive value of bauplan features versus patio ludens, physiological adaptations, hopeful monsters and saltational evolution, the significance and limits of developmental robustness, etc. Rutishauser (2020) discussed the past and future of plant evo-devo. Our conception of

2496-465: The gynoecium and the search for a fossil ancestor of Angiosperms changes fundamentally from the perspective of evo-devo. Whether we like it or not, morphological research is influenced by philosophical assumptions such as either/or logic, fuzzy logic, structure/process dualism or its transcendence. And empirical findings may influence the philosophical assumptions. Thus there are interactions between philosophy and empirical findings. These interactions are

2560-451: The hardiness of the tissue. At freezing temperatures, water in the intercellular spaces of plant tissues freezes first, though the water may remain unfrozen until temperatures fall below 7 °C. After the initial formation of ice intercellularly, the cells shrink as water is lost to the segregated ice. The cells undergo freeze-drying, the dehydration being the basic cause of freezing injury. The rate of cooling has been shown to influence

2624-481: The identification of plants. The detailed study of reproductive structures in plants led to the discovery of the alternation of generations, found in all plants and most algae, by the German botanist Wilhelm Hofmeister . This discovery is one of the most important made in all of plant morphology, since it provides a common basis for understanding the life cycle of all plants. The primary function of pigments in plants

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2688-645: The latter also being rich in Dacrydium and Dacrycarpus species. Podocarpus (with 82 to 100 species) and Dacrydium (with 21 species) are the largest genera. A few genera are common to New Zealand and South America, supporting the view that podocarps had an extensive distribution over southern Gondwanaland . The breaking up of Gondwanaland led to large-scale speciation of the Podocarpaceae. Until 1970, only seven Podocarpaceae genera were recognized: Podocarpus , Dacrydium , Phyllocladus , Acmopyle , Microcachrys , Saxegothaea , and Pherosphaera . All four of

2752-463: The living organism it is not merely a question of spatial structure with an 'activity' as something over or against it, but that the concrete organism is a spatio- temporal structure and that this spatio-temporal structure is the activity itself". For Jeune, Barabé and Lacroix, classical morphology (that is, mainstream morphology, based on a qualitative homology concept implying mutually exclusive categories) and continuum morphology are sub-classes of

2816-418: The molecules in a plant are not enough to predict characteristics of the cells; and knowing all the properties of the cells will not predict all the properties of a plant's structure. A vascular plant begins from a single celled zygote , formed by fertilisation of an egg cell by a sperm cell. From that point, it begins to divide to form a plant embryo through the process of embryogenesis . As this happens,

2880-448: The more encompassing process morphology (dynamic morphology). Classical morphology, continuum morphology, and process morphology are highly relevant to plant evolution, especially the field of plant evolutionary biology (plant evo-devo) that tries to integrate plant morphology and plant molecular genetics. In a detailed case study on unusual morphologies, Rutishauser (2016) illustrated and discussed various topics of plant evo-devo such as

2944-415: The networks of multicellular development, reproduction, and organ development, contributing to more complex morphogenesis of land plants. Although plants produce numerous copies of the same organ during their lives, not all copies of a particular organ will be identical. There is variation among the parts of a mature plant resulting from the relative position where the organ is produced. For example, along

3008-475: The plant morphologist to interpret structures, and in turn provides phylogenies of plant relationships that may lead to new morphological insights. When structures in different species are believed to exist and develop as a result of common, inherited genetic pathways, those structures are termed homologous . For example, the leaves of pine, oak, and cabbage all look very different, but share certain basic structures and arrangement of parts. The homology of leaves

3072-503: The point in the plant's life when they begin to develop, as well as by the environment to which the structures are exposed. This can be seen in aquatic plants. Temperature has a multiplicity of effects on plants depending on a variety of factors, including the size and condition of the plant and the temperature and duration of exposure. The smaller and more succulent the plant, the greater the susceptibility to damage or death from temperatures that are too high or too low. Temperature affects

3136-408: The primordia accounts for the ability of the hardiest of the boreal conifers to survive winters in regions when air temperatures often fall to -50 °C or lower. The hardiness of the winter buds of such conifers is enhanced by the smallness of the buds, by the evolution of faster translocation of water, and an ability to tolerate intensive freeze dehydration. In boreal species of Picea and Pinus ,

3200-402: The problem of surviving in a hot, dry environment. Plant morphology treats both the vegetative structures of plants, as well as the reproductive structures. The vegetative ( somatic ) structures of vascular plants include two major organ systems: (1) a shoot system , composed of stems and leaves, and (2) a root system . These two systems are common to nearly all vascular plants, and provide

3264-432: The process by which structures originate and mature as a plant grows. While animals produce all the body parts they will ever have from early in their life, plants constantly produce new tissues and structures throughout their life. A living plant always has embryonic tissues. The way in which new structures mature as they are produced may be affected by the point in the plant's life when they begin to develop, as well as by

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3328-431: The process of organogenesis . New roots grow from root meristems located at the tip of the root, and new stems and leaves grow from shoot meristems located at the tip of the shoot. Branching occurs when small clumps of cells left behind by the meristem, and which have not yet undergone cellular differentiation to form a specialised tissue, begin to grow as the tip of a new root or shoot. Growth from any such meristem at

3392-462: The rate of biochemical and physiological processes, rates generally (within limits) increasing with temperature. However, the Van’t Hoff relationship for monomolecular reactions (which states that the velocity of a reaction is doubled or trebled by a temperature increase of 10 °C) does not strictly hold for biological processes, especially at low and high temperatures. When water freezes in plants,

3456-440: The resulting cells will organise so that one end becomes the first root, while the other end forms the tip of the shoot. In seed plants, the embryo will develop one or more "seed leaves" ( cotyledons ). By the end of embryogenesis, the young plant will have all the parts necessary to begin in its life. Once the embryo germinates from its seed or parent plant, it begins to produce additional organs (leaves, stems, and roots) through

3520-425: The same mature tree. Juvenile cuttings taken from the base of a tree will form roots much more readily than cuttings originating from the mid to upper crown. Flowering close to the base of a tree is absent or less profuse than flowering in the higher branches especially when a young tree first reaches flowering age. The transition from early to late growth forms is referred to as ' vegetative phase change ', but there

3584-421: The same or different species, then draws comparisons and formulates ideas about similarities. When structures in different species are believed to exist and develop as a result of common, inherited genetic pathways, those structures are termed homologous . For example, the leaves of pine, oak, and cabbage all look very different, but share certain basic structures and arrangement of parts. The homology of leaves

3648-575: The seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted

3712-462: The structures are similar. It is quite likely that similar underlying causes of genetics, physiology, or response to the environment have led to this similarity in appearance. The result of scientific investigation into these causes can lead to one of two insights into the underlying biology: Understanding which characteristics and structures belong to each type is an important part of understanding plant evolution. The evolutionary biologist relies on

3776-427: The study of cells using optical microscopy . At this scale, plant morphology overlaps with plant anatomy as a field of study. At the largest scale is the study of plant growth habit , the overall architecture of a plant. The pattern of branching in a tree will vary from species to species, as will the appearance of a plant as a tree, herb, or grass. Fourthly, plant morphology examines the pattern of development ,

3840-476: The subject of what has been referred to as philosophy of plant morphology. One important and unique event in plant morphology of the 21st century was the publication of Kaplan's Principles of Plant Morphology by Donald R. Kaplan, edited by Chelsea D. Specht (2020). It is a well illustrated volume of 1305 pages in a very large format that presents a wealth of morphological data. Unfortunately, all of these data are only interpreted in terms of classical morphology and

3904-537: The timing of the KNOX gene expression!." Eckardt and Baum (2010) concluded that "it is now generally accepted that compound leaves express both leaf and shoot properties.” Process morphology describes and analyses the dynamic continuum of plant form. According to this approach, structures do not have process(es), they are process(es). Thus, the structure/process dichotomy is overcome by "an enlargement of our concept of 'structure' so as to include and recognise that in

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3968-435: The tip of a root or shoot is termed primary growth and results in the lengthening of that root or shoot. Secondary growth results in widening of a root or shoot from divisions of cells in a cambium . In addition to growth by cell division, a plant may grow through cell elongation . This occurs when individual cells or groups of cells grow longer. Not all plant cells will grow to the same length. When cells on one side of

4032-549: The use of this term solely within the book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,

4096-460: Was segregated from Lagarostrobus , based on morphological characteristics . In 2002, a molecular phylogenetic study showed Sundacarpus is embedded in Prumnopitys and the monophyly of Lagarostrobos is doubtful if Manoao is included within it. More recent treatments of the family have recognized Manoao , but not Sundacarpus . Molecular evidence supports Podocarpaceae being

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