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They are a group of seed producing plants, which include Coniferophyta,Ginkgophyta,Cycadophyta and Gnetophyta. Angiosperms: Flowering plants approx. 300,000 They are divided into two main classes the monocotyledons and dicotyledons, produce seeds that are protected by fruits.
Flowering plants or angiosperms are divided into two large groups. Monocotyledons or monocots have one seed lobe, which is often modified to absorb stored nutrients from the seed so never emerges from the seed or becomes photosynthetic. Dicotyledons or dicots have two cotyledons and often germinate to produce two leaf-like cotyledons.
The spermatophytes were traditionally divided into angiosperms, or flowering plants, and gymnosperms, which includes the gnetophytes, cycads, [5] ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, [ 6 ] in particular based on vessel elements .
They constitute one of the major groups into which the flowering plants have traditionally been divided; the rest of the flowering plants have two cotyledons and were classified as dicotyledons, or dicots. Monocotyledons have almost always been recognized as a group, but with various taxonomic ranks and under several different names.
The dicotyledons, also known as dicots (or, more rarely, dicotyls), [2] are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, that the seed has two embryonic leaves or cotyledons. There are around 200,000 species within this ...
Conservation in this context is the attempt to prevent extinction, whether in situ by protecting plants and their habitats in the wild, or ex situ in seed banks or as living plants. [88] Some 3000 botanic gardens around the world maintain living plants, including over 40% of the species known to be threatened, as an "insurance policy against ...
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The oldest viable carbon-14-dated seed that has grown into a plant was a Judean date palm seed about 2,000 years old, recovered from excavations at Herod the Great's palace on Masada in Israel. It was germinated in 2005. [ 73 ] (