There are two main types of seed plants. Gymnosperms are the types of seed plants that produce naked seeds, or seeds that are not covered or grown inside pods of fruits. The second type of seed plant is the angiosperm. The angiosperm is the type of seed plant that produces flowers. The flowers eventually form into fruits that contain the seeds. The types of seed plants can be broken down further.
Conifers are the types of plants that typically produce seeds in cones. Evergreen trees or shrubbery with needles of scale leaves are conifer seed plants. The cones on these plants are modified leaves that house and protect the structures that produce the spores and seeds. Redwoods and sequoias are examples of this kind of seed plant as well as cedar and pine trees.
One of the oldest kinds of seed plants is the cycad family. Cycads resemble palm trees with a single, branchless trunk that has many leaf sprouts and twigs protruding from the top of the branch. Cycads are often mistaken for palm trees and are found in tropical locations. Ferns are another example of the cycad kind of seed plant.
The ginkgo tree is the only species of plant in the Ginkoatae class. This kind of seed plant is often considered a conifer because the reproductive process of the two seed plants is similar. Ginkgo trees, unlike other trees, produce seeds inside a tiny fleshy covering that is not protected within a seedpod or a fruit.
Gnetophytes bridge the gap between the two types of plants--angiosperms and gymnosperms--because they are considered gymnosperms but more closely resemble the flowering angiosperms plants. Gnetophytes have unprotected seeds that grow in bunches, but have wooden vessels like angiosperms.
Monocots are the first of the two kinds of seed plants in the angiosperm type of seed plants. Monocots have only one seed leaf and seeds that mature inside a pod or fruit. Monocot leaves have parallel veins and the flowers of monocots typically have petals that are arranged in multiples of three.
The second kind of angiosperm seed plant is the dicot. Dicots have two seed leaves and also develop their seeds in either a seed pot or inside a fruit. Dicots have flower petals arranged in fours, fives or numerous petals on one flower. The leaf veins of a dicot are arranged in a net, rather than running parallel to one another.
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