Puncture Vine_ (Tribulus terrestris)_ is a poisonous plant. The fruit consists of burs with sharp spines, which can puncture the skin of human beings and animals. They can also rupture a bicycle tire (hence the name) and penetrate shoe soles. The leaves contain compounds known as saponins, which are toxic to livestock.

Moth mullein (Verbascum blattaria) is a biennial plant that grows in wastelands and farms. It resembles an orchid with white or yellow flowers that are clustered along the stalk. It multiplies rapidly and is considered an invasive weed. Plant parts have been used for centuries as a natural cockroach repellent. Grows from 30 to 91 cm tall.

Petty spurge (Euphorbia peplus) is an annual plant from Europe, Asia, and Africa. It is fast-growing and has become invasive in some countries because it outcompetes other species for resources such as moisture and sunlight. Petty spurge latex is mildly toxic, has nevertheless attracted the attention of researchers in the US and Germany who hope to isolate useful compounds from it.

Portulaca oleracea, colloquially known as common purslane, is an annual succulent species with reddish stems and tiny yellow, five-petal flowers. It is used for culinary purposes in various parts of the world, most often raw, in salads. Common purslane is also a good companion plant for crops that thrive in moist soils.

Experts consider johnson grass (Sorghum halepense) to be one of the ten worst weeds in the world. If frost or heat causes the plant to wilt, it can produce enough hydrogen cyanide to kill livestock. It grows at such a prodigious rate, it can choke out other crops. It’s named after Colonel William Johnson, an Alabama plantation owner who sowed lots of its seed around 1840.

Brown knapweed (Centaurea jacea) is a perennial flowering plant that grows in woodland clearings, yards, ditches, and pastures. Brown knapweed is native to Europe. This plant is categorized as an invasive species in most places where it grows.

In warmer climates, the downy thorn-apple is an invasive perennial. In colder zones, it’s an annual that can be controlled. It is native to East Africa and is naturalized in China. It is not currently a problem in the United States, but it would become invasive if it were introduced. The reason for this is that the plant will quickly establish itself and spread rapidly. It is cultivated in gardens, but care must be taken to prevent it from overtaking other plants. The weed poses another threat: it is highly toxic to humans and animals. There are not any current bans on the sale, transport, or cultivation of the plant, but it is generally not encouraged.

Parthenium hysterophorus or santa Maria feverfew is also called famine weed. It is an invasive weed that can disrupt the health of crops, pasture, livestock, and humans. A substance in the plant, called parthenin, is highly toxic and can cause dermatitis and breathing difficulties in humans and animals.

Prickly lettuce, in spite of its appearance, is the closest wild relative of cultivated lettuce. Even though it is widely considered a weed, it can be used in the kitchen. Young leaves of prickly lettuce are edible and the bitter milky latex can also be made into a condiment or to add flavor to salads. Consuming in large quantities could cause digestive upsets.

Spreading dogbane (*Apocynum androsaemifolium*) is a plant species that is prevalent in North America. It grows in all the United States except for some areas of the Southeastern states. Its delicate bunches of fragrant flowers and nectar provide an important food source for the monarch butterfly. However, this plant is toxic to pets, livestock, and humans. It spreads by rhizomes and appears in distinct patches.

The crown Flower has beautiful flowers that are used to make leis and were a favorite of the last queen of Hawaii. The outer petals of this flower curl back, and reveal what looks like a crown inside. The sap of this plant may cause skin irritation and can be considered toxic.

Jimsonweed (Datura stramonium) is a species of nightshade plant native to Central America which is considered an invasive species in more temperate climates. It can be toxic if ingested in significant quantities. It has a distinctive, strong smell. The jimsonweed gets its common name from Jamestown, Virginia, where soldiers ingested the plants exhibited altered mental states afterward.

Texas thistle (Cirsium texanum) is a plant species that attracts the painted lady butterfly. In addition, goldfinches love to eat texas thistle seeds and the silky material that surrounds the seeds. This plant's flowers look like miniature pom-poms and can be either pink or lavender.

Lily Of The Valley Vine (Salpichroa origanifolia), a member of the nightshade family, is a perennial creeping plant native to South America but widely naturalized elsewhere. While it is often grown as an ornamental, it can also be considered an invasive weed because its vigorous growth may smother other plants and extensive, shallow roots make it difficult to eradicate.

Asthma-plant (Euphorbia hirta) is a ground-hugging spurge weed whose branches can grow to 61 cm long. It blooms from summer through early fall, dying off after the first frost. A milky sap will seep from broken stems or leaves. It can be a nuisance weed that reproduces rapidly.