Potentilla genus is native to both the Old and New World in the Northern Hemisphere.  There are about 500 species in this large genus.  These are herbs  and shrubs with alternate compound leaves with solitary yellow, white, or purple flowers.  The flowers usually have five petals, but sometimes only four petals. There are about  78 species and 68 subspecies or varieties growing in greater North America.  Several of the species frequently placed in this genus have been moved by some modern  authors to other genera including Potential fruiticosa, Potentilla palustris,  and Potentilla anserina.   Here they are retained in the Potentilla genus.

Rose Family has been arbitrarily divided into several different parts to facilitate study. This portion contains the small wild plants in the family. Included herein are wild roses, strawberries, raspberries, and other related plants. (The rose hybrids, Spiraea, and fruit trees are the other sections created to study this large family.)

Rose Family (Rosaceae) of the Rose Order contains the Rose genus and is a very large diverse family containing not only the roses, but many small weeds and also the important fruit trees including the apple, cherry, pear, and plum. Along with the Grass and Legume Families, this family is one of the most important of all plant groups. There are over 3,000 species in this family organized into over 100 different genera. There are over 840 species growing in greater North America. Typical flowers in this family have five petals and five sepals.

Here the family is divided as follows:

A) Miscellaneous small wild plants such as roses, strawberries, et cetera
B) Rose hybrids of interest to the flower gardener
C) Spiraea group (which forms a natural subfamily)
D) Fruit trees and hawthorns, et cetera

Rose Group (Order Rosales) contains many large and very important families. Included here are fruit trees in the family Rosaceae, the nitrogen fixing plants like clover and alfalfa (in the family  Leguminosae), and a large assemblage of plants divided into over fifteen different families.

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.