Environment Reference Libraries

Perennial plants live for two years or more. Perennials differ from annuals and biennials with annuals replanted every year and biennials every other year. Perennial’s that bloom during spring and summer will die back in autumn, rest during the winter, then re-grow the following spring from the existing root-stock; these are also known as deciduous perennials. If the climate is continually...

Biennial plants have a two year life cycle; roots, stems and leaves in the first year with flowers following the next year after a cold winter dormant period. Biennials will produce seed and fruit before dying. There are not as many biennial plants as there are perennials or annuals. Biennial plants, when exposed to extreme climate conditions, may have a shortened life cycle of a few months...

Annuals are plants that flower and/or set fruit in one growing season. Most vegetables are annuals as well as domesticated grains. Vegetables such as carrot and celery are biennials grown as an annual whereas tomato and bell pepper are perennials and grown as an annual. Annuals grow well mixed in with perennials and biennials. There are also ornamental flowers that are perennials in one region...

Voyageurs National Park is located in the state of Minnesota in the United States. The park contains 218,200 acres of land ancient Native Americans. The first explorers of European descent arrived in the area in 1688. These were French fur traders and explores, known as voyageurs, the people for which the park was named. Logging began in 1880’s and 1890’s and was such a lucrative and...

Shenandoah National Park is located in the State of Virginia in the United States. The park contains a portion of the Blue Ridge Mountains and holds 199,100 acres of land, of which 79,579 acres comprise a designated wilderness. The park extends across a narrow area, through eight counties, from Waynesboro to the town of Front Royal. The establishment of Shenandoah National park began in...

The depressed river mussel or compressed river mussel, Pseudanodonta complanata, is a species of freshwater mussel, an aquatic bivalve mollusk belonging to the family Uniondae, the river mussels. The species name comes from the flattened shape of its shell. This species can be found throughout northern Europe, but it’s endangered throughout its range. While the survival of this species...

Pinctada maxima is a species of pearl oyster, a marine bivalve mollusk belonging to the family Pteriidae, the pearl oysters. There are two different color varieties: the White lipped oyster and the Gold lipped oyster. These bivalves are considered to be the largest pearl oysters in the world. They have a very strong inner shell layer composed of nacre, also known as “mother of pearl”....

The Flat Tree Oyster, Isognomon alatus, is a species of bivalve mollusk belonging to the family Isognomonidae. It can be seen along the Atlantic coast of North America, ranging from southern Florida to Brazil and Bermuda. This oyster has two thin and irregularly shaped valves that are joined by a long straight hinge. The exterior is sculpted by a large number of rough, concentric rings with...

The Noble Pen Shell, Pinna Nobilis, is a species of large saltwater clam, a marine bivalve mollusk belonging to the family Pinnidae. This bivalve shell can be as large as almost 3 feet in length, and the shape is somewhat variable. Like all pen shells, it is quite fragile. It attaches itself to rocks using a strong byssus made up of many silk like hairs. These are fibers that are secreted by...

Desert greening is made up of any number of methods used to revitalize deserts. So far, only arid and semi-arid desert are meant when using this expression. The icy deserts and other types are considered to be unsuitable. The different methods include landscaping methods to reduce evaporation, erosion, consolidation of topsoil, temperature, sandstorms and more, permaculture in general,...