The basis for their diversity comes from their incredible reproductive success in a wide variety of habitats. The success of this group is also reflected by the diversity of their flowers that show astonishing displays of different forms, sizes, shapes, and colors all of these to lure pollinators and effect sexual reproduction. Flowers are considered as an organ system because they are made up of two or more sets, or whorls, of leaflike structures. A typical flower is composed of four whorls, which are the sepals, petals, stamens, and apistil with one or more carpels.
Seeds - Types of Seeds - Selecting Seeds Information on seeds, seed types, discussion on hybrid versus heirloom seeds. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant.
The formation of the seed completes the process of reproduction in seed plants started with the development of flowers and pollinationwith the embryo developed from the zygote and the seed coat from the integuments of the ovule.
Seeds have been an important development in the reproduction and spread of flowering plants, relative to more primitive plants like mosses, ferns and liverworts, which do not have seeds and use other means to propagate themselves.
This can be seen by the success of seed plants both gymnosperms and angiosperms in dominating biological niches on land, from forests to grasslands both in hot and cold climates. The term seed also has a general meaning that predates the above anything that can be Monocots dicots i.
In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or hull, and the potato is a tuber.
A typical seed includes three basic parts: The embryo is an immature plant from which a new plant will grow under proper conditions. The embryo has one cotyledon or seed leaf in monocotyledons, two cotyledons in almost all dicotyledons and two or more in gymnosperms.
The radicle is the embryonic root. The plumule is the embryonic shoot. The embryonic stem above the point of attachment of the cotyledon s is the epicotyl.
The embryonic stem below the point of attachment is the hypocotyl. Within the seed, there usually is a store of nutrients for the seedling that will grow from the embryo. The form of the stored nutrition varies depending on the kind of plant. In angiosperms, the stored food begins as a tissue called the endosperm, which is derived from the parent plant via double fertilization.
The usually triploid endosperm is rich in oil or starch and protein. In gymnosperms, such as conifers, the food storage tissue is part of the female gametophyte, a haploid tissue. In some species, the embryo is embedded in the endosperm or female gametophyte, which the seedling will use upon germination.
In others, the endosperm is absorbed by the embryo as the latter grows within the developing seed, and the cotyledons of the embryo become filled with this stored food. At maturity, seeds of these species have no endosperm and are termed exalbuminous seeds.
Some exalbuminous seeds are bean, pea, oak, walnut, squash, sunflower, and radish. Seeds with an endosperm at maturity are termed albuminous seeds.
|Flowering Plant Family Identification||During the Gold Rush, miners ate nearly 80, frogs per year.|
All gymnosperm seeds are albuminous. The seed coat or testa develops from the tissue, the integument, originally surrounding the ovule.
The seed coat in the mature seed can be a paper-thin layer e. The seed coat helps protect the embryo from mechanical injury and from drying out.
In addition to the three basic seed parts, some seeds have an appendage on the seed coat such an aril as in yew and nutmeg or an elaiosome as in Corydalis or hairs as in cotton.
There may also be a scar on the seed coat, called the hilum; it is where the seed was attached to the ovary wall by the funiculus. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms "enclosed seeds" from the gymnosperms "naked seeds".
Angiosperm seeds are produced in a hard or fleshy or with layers of both structure called a fruit that encloses the seeds, hence the name.
In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales as they develop in some species of conifer. Kinds of seeds There are a number of modifications to seeds by different groups of plants.
One example is that of the so-called stone fruits such as the peachwhere a hardened fruit layer the endocarp surrounds the actual seed and is fused to it.
Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Angiosperm seeds consist of three genetically distinct constituents: In angiosperms, the process of seed development begins with double fertilization and involves the fusion of the egg and sperm nuclei into a zygote.Flowers of Monocots and Dicots.
Floral variation provides part of the basis for dividing the flowering plants into two major groups: the dicotyledonsand the monocotyledons.
The five main characters I like to use are Leaves, Roots, Stems, Cotyledons, and Flowers. Flowers. Monocots tend to have flower parts in multiples of 3.
Different types of flowers (the Angiosperms) can easily be identified by dividing them into Monocots or timberdesignmag.com just looking at one flower we should soon be able to identify it as one or the other.
Montana Field Guide contains a wealth of information about Montana's diverse species. Select the characters (states) that are present in the specimen being identified. Press Submit when ready to determine possible families. Pressing "Back" at the top of the window brings you back to this page keeping your character selections.
Comparison with monocotyledons. Aside from cotyledon number, other broad differences have been noted between monocots and dicots, although these have proven to be differences primarily between monocots and timberdesignmag.com early-diverging dicot groups have "monocot" characteristics such as scattered vascular bundles, trimerous flowers, .