Clematis genus is native to both the Old and New World in both the northern and southern hemispheres.  Some genera are also found in the mountains of tropical Africa.   There are over 200 species in this genus. These plants are climbers and are usually woody or semi-woody perennials.  The leaves are generally opposite,  on slender petioles, and pinnately compound.  Many of these species have large flowers and make excellent garden specimens.  There were 37 species and 15 subspecies growing in greater North America as of 1994.

Buttercup Family (Ranunculaceae) reaches its greatest development in North America, Europe, and the Orient. The family has approximately 1500 species organized into about thirty-five different genera. With the exception of the Genus Paeonia (which might even belong in a different family) most of the species are soft-stemmed annual or perennial herbs. The leaves are usually alternate (except for Clematis). Flowers may be regular or irregular. In the buttercup family, there are 26 genera with 318 species growing in greater North America.

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.

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 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.