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Vascular Plants - Phylum: Tracheophyta
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Tracheophytes (from Greek: 'Trachea' = 'tube') or Vascular Plants are so called because they possess specialized tissue for the transportation of water and nutrients upwards within the plant and, tissue for the transportation of water and glucose downwards. These 'tissues' are essentially bundles of tubes through which the water and glucose/nutrients flow.
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Vascular Plants are the plants most of us are familiar with. They usually have roots, a stem and leaves, but not necessarily all three. Many also produce flowers. The vascular tissues are called 'xylem' and 'phloem'. The 'xylem' can become 'lignified' , become woody, and the rigidity provided by wood means the plant can grow to considerable size.
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Not the adult of the species but a 'sporophyte' nonetheless.
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When we look at any Vascular Plant we usually see the 'adult' or 'sexual phase' form, the so called 'sporophyte' which can produce both male and female 'spores' (eggs and pollen). The cells that make up the 'adult' plant all contain two sets of chromosomes in the nucleus. The 'spores' each contain one set, but once male and female spores combine, usually to produce what we know as a seed, there will be two sets again. The seed than can germinate and develop into a 'sporophyte' once there are suitable conditions.
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There are other features however that set the Vascular Plants apart. They can grow in just about any environment whereas non-vascular plants are often limited to humid and/or shady places. There usually are leaves present in Vascular Plants and they are often well protected against moisture loss and often equipped (they have 'stomata') for gaseous exchange, i.e. carbon dioxide in and oxygen out. The 'opposition', does not.
Vascular Plants normally have a well developed root system with which to anchor themselves in place. And, often, they have a stem. Within this stem are a number of different cells for varying functions, including, support and rigidity; transportation of water and nutrients, the xylem and the phloem, of course; protection from the elements, i.e. the outer layers such as bark. And, the stem also helps in the competition for light by elevating the leaves. Likewise, the flowers are raised to make them more accessible to pollinators.
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Stem, flowers, leaves and, it's all up there.
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The Phylum, Tracheophyta, contains six Classes, four of which have resident members here in the Northern rivers region. There is also one sub-phylum, the Angiospermae or Flowering Plants. The Angiospermae is split into two Classes both of which have endemic species in the Northern Rivers. (More about Angiosperms below.)
Flowering Plants - Subphylum: Angiospermae
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The sub-phylum, Angiospermae or Flowering Plants contains Two Classes, the Liliopsidae or Monocotyledons (Monocots) and the Magnoliopsidae or Dicotyledons (Dicots). Of the two, the Magnoliopsidae are definitely the more complex group, containing fifty-three Orders. Thirty-four of these have representatives in the Northern Rivers. The Liliopsidae is divided into eleven Orders, nine of which can be encountered locally.
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One of the differences between the Monocots and the Dicots can be found in the names themselves. A Cotyledon is an embryonic leaf present in a seed from a seed-bearing, or flowering plant. These embryonic leaves are the first to appear above the ground as the seed germinates. Monocots, such as Corn, have only one, and Dicots, such as Beans, have two. There are however other differences between the two.
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There are four more differences between Monocots and Dicots that are easily picked up. For starters, the leaves on Monocots usually have parallel veins whereas the Dicots usually have veins that radiate from a single point at the base of the leaf, i.e. arranged like a fan.
Monocot flowers usually carry their floral parts in multiples of three. Dicots usually in multiples of four or five. And then, there's the roots of the plant. Monocots tend to have a fibrous root system with thin roots going everywhere straight from the bottom of the plant. Dicots on the other hand tend to have a pronounced tap root. Finally, the manner in which the vascular bundles are arranged is different.
In Monocots, the bundles are apparently spread randomly throughout the stem whereas in Dicots the bundles are arranged in a single ring towards the outside of the stem.
Monocot flowers usually carry their floral parts in multiples of three. Dicots usually in multiples of four or five. And then, there's the roots of the plant. Monocots tend to have a fibrous root system with thin roots going everywhere straight from the bottom of the plant. Dicots on the other hand tend to have a pronounced tap root. Finally, the manner in which the vascular bundles are arranged is different.
In Monocots, the bundles are apparently spread randomly throughout the stem whereas in Dicots the bundles are arranged in a single ring towards the outside of the stem.
References and links:
Text:
Erik Beringen.
Erik Beringen.