Rutgers Gardens, New Brunswick - NJ, USA

The flowering plants (angiosperms), also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies (derived characteristics). These characteristics include flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure; they are fruiting plants, although more commonly referred to as flowering plants.

The ancestors of flowering plants diverged from gymnosperms around 245–202 million years ago, and the first flowering plants known to exist are from 140 million years ago. They diversified enormously during the Lower Cretaceous and became widespread around 100 million years ago, but replaced conifers as the dominant trees only around 60–100 million years ago.

Vascular plants (from Latin vasculum: duct), also known as tracheophytes (from the equivalent Greek term trachea) and also higher plants, form a large group of plants that are defined as those land plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have (non-lignified) tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta and Tracheobionta.

Iris is a genus of 260–300 species of flowering plants with showy flowers. It takes its name from the Greek word for a rainbow, referring to the wide variety of flower colors found among the many species. As well as being the scientific name, iris is also very widely used as a common name for all Iris species, though some plants called thus belong to other closely related genera. A common name for some species is 'flags', while the plants of the subgenus Scorpiris are widely known as 'junos', particularly in horticulture. It is a popular garden flower.

The often-segregated, monotypic genera Belamcanda (blackberry lily), Hermodactylus (snake's head iris), and Pardanthopsis (vesper iris) are currently included in Iris.

This is a partial list of garden plants, plants that can be cultivated in the garden, listed alphabetically by genus. See also list of plants by common name.

Plants cannot move to escape their predators, so they must have other means of protecting themselves from herbivorous animals. Some plants have physical defenses such as thorns, but by far the most common protection is chemical. Over millennia, natural selection has produced a complicated and vast array of chemical compounds that deter herbivores. Tannin is a compound that emerged relatively early in the evolutionary history of plants, while more complex molecules such as polyacetylenes are found in younger groups of plants such as the Asterales. Many of the plant defense compounds arose to defend against consumption by insects, although when livestock or humans consume such plants, they may also experience negative effects, ranging from mild discomfort to death.

Many of these poisonous compounds also have important medicinal benefits. There are so many kinds of plant defenses that there are many unanswered questions about them. Questions include (1) which plants have which type of defenses, (2) which herbivores are the plants defended against, (3) what are the chemical structures of the compounds that provide defense, (4) and what are the potential medical uses of these compounds? This is still an active area of research with important implications for understanding plant evolution, and for medical research.

Below is an extensive, if incomplete, list of plants containing poisonous parts that pose a serious risk of illness, injury, or death to humans or animals. Human fatalities caused by poisonous plants – especially resulting from accidental ingestion – are rare in the USA.

The Flora of North America North of Mexico (usually referred to as FNA) is a multivolume work describing the native plants of North America. Much of the Flora is already available online. It is expected to fill 30 volumes when completed, and will be the first work to treat all of the known flora north of Mexico.

It is a collaboration of over 800 authors, who collaborate over the web.

These flowers come into bloom in early spring:

An ornamental bulbous plant, often called an ornamental bulb or just a bulb in horticulture, is a plant grown for ornamental purposes which is able to be sold as dried underground or ground level storage organs. Botanists distinguish between true bulbs, corms, tubers, rhizomes, and tuberous roots, any of which may be termed "bulbs" in horticulture. Such storage organs contain moisture and nutrients and are used to survive winter or other adverse conditions such as summer drought and heat (estivation) in a dormant state. The resting period may be in winter or summer, depending on the species under consideration.