Most botanists believe that the Pteridophytes also known as ferns are descendants of the Rhyniopsida, an extinct group of free-sporing plants which originated in the Silurian period (about 430 million years ago) and went extinct in the mid-Devonian period (about 370 million years ago).
Ferns has no flowers, no seeds, and no fruits. A fern is defined as a cryptogam which means a plant that has no true flowers or seeds. With sporangia, a receptacle in which asexual spores are formed evolving from the leaf.
A fern plant generally consists of one or more fronds attached to a rhizome, which is a continuously growing horizontal underground stem. A frond is simply the leaf of the fern. The sizes of ferns and their fronds vary considerably among the different species.
The fern frond develops from a leaf bud referred to as a crozier. The crozier is coiled up in most species, with the frond apex at the middle of the coil. The reproductive cells of ferns are microscopic spores which are often clustered together in the brown spots visible on the fronds ' undersides.
Habitat and distribution
The majority of ferns inhabit warm, damp areas of the Earth. Growing mostly in tropical areas, ferns diminish in number with increasingly higher latitudes and decreasing supplies of moisture. Some ferns play a role in ecological succession, growing from the crevices of bare rock exposures and in open bogs and marshes prior to the advent of forest vegetation. The best known fern genus over much of the world, is often succeeded by woody vegetation. Because of their ability to disperse by spores and their capacity to produce bothsex organs on the same gametophyte, it would seem logical to assume that fern...
... middle of paper ...
...The second stage in the life cycle of a fern is the adult stage. If direct sunlight falls onto the young fronds for an extended period of time, the plant may die easily. When the veins are matured, moisture from the ground will be transported easily to the outermost leaves and the plant can withstand periods of direct sunlight. After the plant is large and mature, it will grow spores on the undersides of its leaves and the life cycle of a fern will begin again.
Ferns consist of stems, leaves and roots.
Stems: Fern stems are often referred to as rhizomes, even though they grow underground only in a some of the species.
Leaf: The green, photosynthetic part of the plant is technically a megaphyll and in ferns, it is often referred to as a frond.
Roots: The underground non-photosynthetic structures that take up water and nutrients from soil.
Need Writing Help?
Get feedback on grammar, clarity, concision and logic instantly.Check your paper »
- Introduction Plants exhibit exceptionally intelligent behaviour when it comes to interactions with their environment. They can detect perceived threats, then convey warning signals to other plants via chemical signaling. Forewarned plants will then assemble their defenses against these potential threats, thus, increasing their chance of survival and reproduction. Communication and competition are common occurrences among the plant world. Another brilliantly, almost inconceivable capability plants possess is the ability to recognize coexisting family members within their home range.... [tags: Environment, Plant Species, Plant Communication]
1519 words (4.3 pages)
- Rosemary Asexual: Softwood cuttings Steps Select a healthy rosemary plant cutting with good genetics that has new growth branches on it. This helps with growing softwood cuttings from scratch. >Why I did this step is because getting good genetics and softwood cutting has more growing hormone to get it started. Also having a healthy plant from the start helps because due to the fact is has no diseases. Then cut it on a 45 degree angle about 5 to 10 cm from the top of the cutting use secateurs make sure they are sharp and sterilized before cutting,as they can transfer plant diseases and destroy the cells on the cuttings.... [tags: Germination, Seed, Plant, Plant morphology]
1747 words (5 pages)
- Many problems arose when conducting this experiment. Initially, I planned to record results every day for the plants, however, the plants did not always grow every day. The plant which received the most light in particular did not show many results initially as it took it up to nine days before recording results was possible. This was a set back and I ended up having to change the times at which I was recording results. I ended up measuring a day apart and then waited 3-4 days before recording results again.... [tags: Light, Photosynthesis, Plant, Fern]
2026 words (5.8 pages)
- PART A: Topic Overview What are plants. Plants are vital for human survival and important for human well-being. Everything depends on plants. Plants are alive and have needs just like people and animals. Plants need air, water, nutrients, and sunlight so they can stay alive. One characteristic that distinguishes plants from most other living things is the ability to make their own food. This process is called photosynthesis. Photosynthesis is when plants use energy from the sun to grow and reproduce.... [tags: Photosynthesis, Chlorophyll, Plant]
1851 words (5.3 pages)
- Kalanchoe is part of the Crassulaceae plant family, which includes relatives such as Jade and Stonecrop. A native of Madagascar, the plant requires sun and a well-drained, light soil, one suitable for cacti. There are over 125 species of the Kalanchoe tropical plants, only one species of the crassulaceae family originates from the America, 56 from southern & eastern Africa and 60 species in Madagascar. They are also found in south-eastern Asia and China. The name Kalanchoe comes from a phonetic transcription of the Chinese words 'Kalan Chauhuy' meaning "that which falls and grows", likely in reference to the plantlets that drop from many of the species but others believe it from the ancient... [tags: house plant, leaves]
724 words (2.1 pages)
- The acidity or alkalinity level is dictated by the pH, potential of hydrogen, scale. Soil pH or soil reaction is an implication of the acidity or alkalinity of soil and is measured in pH units. Soil pH is characterized as the negative logarithm of the hydrogen particle fixation. As the measure of hydrogen particles in the soil builds the soil pH diminishes along these lines getting to be more acidic. From pH 7 to 0 the soil is progressively more acidic and from pH 7 to 14 the soil is progressively more alkaline or basic.... [tags: plant development, alkalinity of soil]
997 words (2.8 pages)
- In this investigation different concentrations of Auxin mixtures (no Auxin, 2mg, 10mg and 50mg) were applied to the stem cutting of a Dwarf French Bean plant and in findings which Auxin concentrations had the greatest effect of the growth rate bean plant. In relation to the research question, this investigation was carried out to prove homeostasis in plants. The hypothesis states that when the plant stem is cut, and replaced with an Auxin mixture, which is made up of Ethanol, Lanolin and Auxin powder, is in replacement of the stem.... [tags: Plant morphology, Fern, Plant stem]
1021 words (2.9 pages)
- The obtained results proved that salt stress can affect overall growth of the plant, either weight or length. The shoot as well as root weight decreased under salinity. In this cultivar, root fresh and also dry weights were more affected than those of the shoot. These findings were in agreement of some previous studies, (for example, Khan et al 2013, Munns 2002; Maas and Grattan 1999). The result of these studies showed that a decrease in plants overall growth due to decrement in weight of dry root and shoot, and stem elongation.... [tags: Plant, Photosynthesis, Sodium, Sodium chloride]
896 words (2.6 pages)
- ... Due to certain restrictions, only specific species can act as a vector and that led to specialization of a relationship. It was more of a key and lock mechanism rather than a coincidental coevolution. Since the species that could not get to the specific flower, carried on until it found a suitable one. This therefore does not necessarily mean that either the flower or the vector altered their morphology just to increase the fitness. All of the above arguments are also thought to be the root of the mentioned ‘plant syndrome’ that specifies the pollinator response and the species that acts as a vector.... [tags: floral mechanisms, biology, plant syndrome]
1140 words (3.3 pages)
- Ethnobotany of the Tomato Plant The origin of the cultivated tomato is somewhat unclear. Ethnobotanists and geneticists however have attempted to track down the centre of domestication. "The genus Lycopersicon- the botanical group to which the tomato belongs- is native to western South America, and only Lycopersicon lycopersicum var. cerasiforme, the wild cherry form of the cultivated species, has spread throughout Latin America and the New World Tropics. Second, the tomato was not known in Europe until after the discovery and conquest of America, descriptions and drawings first appearing in the European herbals of the middle and late 16th century.... [tags: Botany Plant Genetics]
506 words (1.4 pages)
- How Does A Person View The Significance And Power Of Knowledge?
- The Argument For Intellectual Property
- Types Of Bleeding Disorders And Its Effects On The Blood
- Critical Issues On The Internet
- Should Health Care Be Provided For Prisoners Confined Within The Penitentiary System?
- The Greatest Ruler Of Rome