Exotic plants are not native to a specific region where they are found. Many exotic plants are invasive--the plants displace native vegetation by taking over areas and pushing native vegetation out of the area. The invasive, exotic plants create an area wherein only that single species lives, which then alters the original environment, including animal life.
Old World Climbing Fern
This fern is native to Australia and Asia and has climbing fronds that grow as much as 100 feet in length. The branches off the main stem are leafy and grow to 4 inches in length. The Old World climbing fern has two types of leaflets on the climbing frond. The unlobed leaflet is the plant's normal leaflet. The lobed leaflet has sporangia on the margin of the leaflet. The sporangia produce spores, which then develop gametophytes--separate plants that produce the Old World climbing fern's sexual cells. The cells form an embryo, which then makes a new climbing fern. The gametophytes are tiny and hard to see.
Jimsonweed is an annual that grows up to 5 feet in height. The stem is pale-green, and the leaves are large and oval. The strong-scented leaves might be green or purple and have coarse teeth on the edges. Jimsonweed produces large, white flowers that are up to 4 inches long. The seeds are about one-eighth inch across and are encased in a prickly capsule. The capsule breaks into four parts once ripened.
Jimsonweed grows in fields, waste lots and overgrazed pastures. It becomes a problem if it takes over an overgrazed pasture, as it is poisonous to animals, though most animals are reluctant to eat it, because of its strong scent. The problems come in when Jimsonweed takes over the entire grazing area, leaving nothing else for animals to eat. The toxins in Jimsonweed are hyoscyamine and scopalamine.
Japanese honeysuckle is a woody vine that grows up to 30 feet long. The younger stems generally have fine hair, and the older stems are hollow with brown bark. The oval-shaped leaves grow up to 2 inches in length and are evergreen or semi-evergreen, depending on how cold the winter is. The flowers are either tubular or trumpet-shaped and range in color from creamy white to pink. The flowers, as they age, turn yellow. The vines also produce black berries. The berries contain the seeds and mature in the fall. In some areas, Japanese honeysuckle is invasive, taking over partially shaded areas at the edges of forests and along streams. It grows over other vegetation, blocking the sun from that vegetation, and eventually pushing native vegetation out by robbing it of light and nutrients.