Narrative

Eurasia milfoil (Myriophyllum spicatum) is very close to Myriophyllum sibiricum and some authors consider them to be the same species.

This lifeform is found in freshwater such as lakes or rivers. This lifeform is locally common. This lifeform is sometimes considered an undesirable species.

This lifeform is found widely in Eurasia. This lifeform is widespread in North America.

Myriophylum genus (water milfoil) is a worldwide genus of about 45 aquatic and terrestrial herbs. There are 14 species established in greater North America. Most of the North American species are very similar in appearance, and can only be reliably separated by minute technical features in the seeds, flowers, etc. The leaves can be in whorls or alternate. In the typical aquatic species, the submerged leaves are whorled and the leaflets are linear. Several of the aquatic species are terrible weeds choking lakes, ponds, and streams. A small amount of bilge water in a trailered boat can permit a species to be introduced to a new body of water. The plants frequently grow in such abundance that they clog the waters and make fishing, sailing, swimming, and water skiing impossible. Many government bodies have tried various methods to rid the waters of these plants. Placing weed cutters on barges, introducing various species of plant-eating fish, and chemicals all have been used with very limited success. Seemingly increased water nutrients from crop and lawn fertilization and septic systems are contributing factors to the tremendous growth of these plants.

Water Milfoil Family (Haloragaceae) is worldwide in distribution with about 100 to 120 species in nine genera. Most of the species are aquatic with alternate or whorled leaves. There are 19 species in four genera growing in greater North America.

Myrtiflorae Order is an assemblage of over twenty 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 (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.