[5][6] The term 'angiosperm' is derived from the Greek words ἀγγεῖον / angeion ('container, vessel') and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit.

Agriculture is almost entirely dependent on angiosperms, and a small number of flowering plant families supply nearly all plant-based food and livestock feed.

Rice, maize and wheat provide half of the world's staple calorie intake, and all three plants are cereals from the Poaceae family (colloquially known as grasses).

The remainder are parasitic, whether on fungi like the orchids for part or all of their life-cycle,[18] or on other plants, either wholly like the broomrapes, Orobanche, or partially like the witchweeds, Striga.

[19] In terms of their environment, flowering plants are cosmopolitan, occupying a wide range of habitats on land, in fresh water and in the sea.

The sundews, many of which live in nutrient-poor acid bogs, are carnivorous plants, able to derive nutrients such as nitrate from the bodies of trapped insects.

[23] As for their growth habit, the flowering plants range from small, soft herbaceous plants, often living as annuals or biennials that set seed and die after one growing season,[24] to large perennial woody trees that may live for many centuries and grow to many metres in height.

Some species grow tall without being self-supporting like trees by climbing on other plants in the manner of vines or lianas.

The 25 most species-rich of 443 families,[32] containing over 166,000 species between them in their APG circumscriptions, are: The botanical term "angiosperm", from Greek words angeíon (ἀγγεῖον 'bottle, vessel') and spérma (σπέρμα 'seed'), was coined in the form "Angiospermae" by Paul Hermann in 1690, including only flowering plants whose seeds were enclosed in capsules.

[35][36] In 1851, with Wilhelm Hofmeister's work on embryo-sacs, Angiosperm came to have its modern meaning of all the flowering plants including Dicotyledons and Monocotyledons.

branch-veined leaves Amborellales Melikyan, Bobrov & Zaytzeva 1999 Nymphaeales Salisbury ex von Berchtold & Presl 1820 Austrobaileyales Takhtajan ex Reveal 1992 Chloranthales Mart.

1835 Asterales Link 1829 Bruniales Dumortier 1829 Apiales Nakai 1930 Paracryphiales Takhtajan ex Reveal 1992 Dipsacales de Jussieu ex von Berchtold & Presl 1820 In 2024, Alexandre R. Zuntini and colleagues constructed a tree of some 6,000 flowering plant genera, representing some 60% of the existing genera, on the basis of analysis of 353 nuclear genes in each specimen.

[50] Molecular evidence suggests that the ancestors of angiosperms diverged from the gymnosperms during the late Devonian, about 365 million years ago.

The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud.

[58][59] The inner series (corolla of petals) is, in general, white or brightly colored, is more delicate in structure, and attracts pollinators by colour, scent, and nectar.

Heteromorphic flowers have carpels and stamens of differing lengths, so animal pollinators cannot easily transfer pollen between them.

When it reaches the micropyle of the ovule, it digests its way into one of the synergids, releasing its contents including the sperm cells.

[70] Some angiosperms, including many citrus varieties, are able to produce fruits through a type of apomixis called nucellar embryony.

[71] Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom[73] in the initial paragraph of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented."

Flowers emerged in plant evolution as an adaptation for the promotion of cross-fertilisation (outcrossing), a process that allows the masking of deleterious mutations in the genome of progeny.

[74] Meiosis in flowering plants provides a direct mechanism for repairing DNA through genetic recombination in reproductive tissues.

[75] Sexual reproduction appears to be required for maintaining long-term genomic integrity and only infrequent combinations of extrinsic and intrinsic factors permit shifts to asexuality.

[75] Thus the two fundamental aspects of sexual reproduction in flowering plants, cross-fertilization (outcrossing) and meiosis appear to be maintained respectively by the advantages of genetic complementation and recombinational repair.

Multiple organizations such as IUCN and Royal Botanic Gardens, Kew suggest that around 40% of plant species are threatened with extinction.

[87] The majority are threatened by habitat loss, but activities such as logging of wild timber trees and collection of medicinal plants, or the introduction of non-native invasive species, also play a role.

[88] Some 3000 botanic gardens around the world maintain living plants, including over 40% of the species known to be threatened, as an "insurance policy against extinction in the wild.