Water shield (Brasenia schreberi) is an aquatic plant with floating leaves. The slender stems and petioles are covered with a slimy material. The leaves are almost circular with the petiole attached to the center of the leaf. The leaves are usually between two and four inches in diameter.

Brasenia genus (water shield) is native to North and South America, and according to some authors also Australia, Africa, and southeast Asia. There is only one species in this genus.

Cabombaceae (Water Shield) family is widely distributed in many small disjoint areas of the world. This family appears naturally absent from Europe and western Asia. These plants are found in fresh water lakes, ponds, and streams. There are two genera (Cabomba and Brasenia) in this family. There are only about six or seven species in this small family. There are three species in two genera found in greater North America.

The leaves can be submerged or floating. The floating leaves are slimy and are peltate (attached to the petiole or stalk near the center and not the edge of the leaf.) The petals are normally three.

In earlier works this family was frequently placed as a subgroup of the water lily (Nymphaeaceae) family. Recent evidence indicates this is a very primitive family, and consequently it should be removed from the Ranales order.

Ranales Order has been broken down into nineteen different families. The water lilies, buttercups, magnolias, and other groups are included in this order. Large pretty flowers seem to be a common characteristic of this order.

The families in this order are in the process of a major re-location. The water lily family (Nymphaeaceae) appears to be an ancient family of plants, and its proper place is open to question. The hornwort (Ceratophyllaceae) family also appears to be a very ancient family, and probably does not belong here either.

Furthermore, the magnolia family (Magnoliaceae) and the buttercup family (Ranunculaceae)are not as closely related to each other as previously presumed, and that is an incentive to further dividing this order.

Until this organization is finalized, we are temporarily retaining this older order.

Dicots (Dicotyledoneae Class) are the predominant group of vascular plants on earth. With the exception of the grasses (Monocots) and the Conifers (Gymnosperms), most of the larger plants that one encounters are Dicots. Dicots are characterized by having a seed with two outer shell coverings.

Some of the more primitive Dicots are the typical hardwood trees (oaks, birches, hickories, etc). The more advanced Dicots include many of the Composite (Aster) Family flowers like the Dandelion, Aster, Thistles, and Sunflowers. Although many Monocots reach a very high degree of specialization, most botanists feel that the Dicots represent the most advanced group of plants.

Seed plants (Phylum Embryophyta) are generally grouped into one large phylum containing three major classes: the Gymnosperms, the Monocots, and the Dicots. (Some scientists separate the Gymnosperms into a separate phylum and refer to the remaining plants as flowering plants or Angiospermae.)

For North American counts of the number of species in each genus and family, the primary reference has been John T. Kartesz, author of A Synonymized Checklist of the Vascular Flora of the United States, Canada, and Greenland (1994). The geographical scope of his lists include, as part of greater North America, Hawaii, Alaska, Greenland, Puerto Rico, and the Virgin Islands.

Kartesz lists 21,757 species of vascular plants comprising the ferns, gymnosperms and flowering plants as being found in greater North America (including Alaska, Hawaii, Greenland, Puerto Rico and the Virgin Islands.

There are estimates within the scientific world that about half of the listed North American seed plants were originally native with the balance being comprised of Eurasian and tropical plants that have become established.

Plant kingdom contains a large variety of different organisms including mosses, ferns, and seed plants. Most plants manufacture their energy from sunlight and water. Identification of many species is difficult in that most individual plants have characteristics that have variables based on soil moisture, soil chemistry, and sunlight.

Because of the difficulty in learning and identifying different plant groups, specialists have emerged that study only a limited group of plants. These specialists revise the taxonomy and give us detailed descriptions and ranges of the various species. Their results are published in technical journals and written with highly specialized words that apply to a specific group.

On the other hand, there are the nature publishers. These people and companies undertake the challenging task of trying to provide easy to use pictures and descriptions to identify those species.

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