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Define flowering plants.

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Some plants produce seeds which are enclosed in flowers or fruit.They are called flowering plants or angiosperms.

Mars is similar to Earth in the fact that both planets have about the same amount of dry land surface. Both planets also have volcanoes and impact basins.

It takes Mars around 24 hours and 37 minutes make full rotation on its axis, while it takes Earth just seconds under 24 hours.

While there are several similarities between the two planets, there are also major differences. For example, Mars is roughly half the size in diameter of Earth. Mars also takes over 650 days to fully rotate the sun, while it takes Earth 365 days. The average surface temperature on Mars is much cooler than on Earth.

The flowering plants, also known as angiosperms, Angiospermae[5][6] or Magnoliophyta,[7] are the most diverse group of land plants, with 416 families, approximately 13,164 known genera and c. 369,000 known species.[8] Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure; in other words, a fruiting plant. The term comes from the Greek words angeion ("case" or "casing") and sperma ("seed").

The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago (mya), and the first flowering plants are known from 160 mya. They diversified extensively during the Early Cretaceous, became widespread by 120 mya, and replaced conifers as the dominant trees from 100 to 60 mya.

Vascular anatomy

Angiosperm stems are made up of seven layers as shown above. The amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings.

In the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles (interfascicular cambium), a complete ring is formed, and a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside. The soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.

Among the monocotyledons, the bundles are more numerous in the young stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases.

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