What are Angiosperms?
Plants are very dynamic things, despite their sedate reputation. They have exciting lives, they make their own food – at least some of them do, and they do humans a big service by consuming carbon dioxide and producing oxygen. Most of the plants in the plant kingdom have tubes that carry water and nutrients throughout the body of the plant. This kind of water-nutrient transportation is called the vascular system. Plants that do not have these are called nonvascular plants. Some vascular plants that have seeds are called gymnosperms. Some of the most common gymnosperms are conifer trees — pine, cedar, spruce, and redwood. These kinds of trees are also evergreens, able to keep their needles even in the cold months of winter. Some of the most advanced plants are the angiosperms. These plants are vascular, and they have seeds, like the gymnosperms. The add-on that makes them so advanced is their ability to have flowers. The main advantage of the flower is to protect the plant’s seeds. Unli
Angiosperms are seed-bearing plants that produce flowers. The flowers are not always showy like the ones in your garden. In fact, some flowers are barely visible at all, but all members of this group have them, including large trees, tiny grasses, and everything in between. Most flowering plants are classified as either monocots or dicots, based on the number of embryonic leaves (also called seed leaves or cotyledons). However, some angiosperms have a mix of both monocot and dicot characters and have unknown relationships. They are included here as other angiosperms.First known fossil occurrence: Cretaceous.Last known fossil occurrence: Quaternary. This group has living relatives.
If one should master the technic for all features of this group, he would be prepared to deal with all the rest; for embryo sacs are so delicate that they are as difficult as the free nuclear stage in the female gametophyte of a gymnosperm, while the peach stone needs a petrotome rather than a microtome. Between these extremes there is everything imaginable in structure, chemical composition, and consistency. Some hints will be given, but the student will gradually learn what should be cut freehand and what should be imbedded; what stages in floral development, what stages in the development of the embryo sac, or what stages in spermatogenesis are likely to be correlated with easily recognized field characters, and what fixing agents are likely to give the best results with various kinds of material. The Vegetative Structures – In stems, roots, and leaves the more delicate structures should be imbedded in paraffin and the more rigid structures should be cut without imbedding at all; bu
The flowering plants or angiosperms are the most widespread group of land plants. The flowering plants and the gymnosperms comprise the two extant groups of seed plants. The flowering plants are distinguished from other seed plants by a series of apomorphies, or derived characteristics. http://en.wikipedia.org/wiki/Flowering_p…
