List of the largest genera of flowering plants


There are over 80 genera of flowering plants estimated to contain at least 500 described species. The largest of these is currently the legume genus Astragalus, with over 3,000 species.
The sizes of plant genera vary widely from those containing a single species to genera containing thousands of species, and this disparity became clear early in the history of plant classification. The largest genus in Carl Linnaeus' seminal Species Plantarum was Euphorbia, with 56 species; Linnaeus believed that no genus should contain more than 100 species.
Part of the disparity in genus sizes is attributable to historical factors. According to a hypothesis published by Max Walters in 1961, the size of plant genera is related to the age, not of the taxon itself, but of the concept of the taxon in the minds of taxonomists. Plants which grew in Europe, where most of the early taxonomy was based, were therefore divided into relatively small genera, while those from the tropics were grouped into much larger and more heterogeneous genera. Likewise, plants which shared common medicinal properties, such as the many species of Euphorbia, were united into a single genus, while plants of diverse uses, such as the grasses, were split into many genera. Where there were many classical names for groups of plants, such as in Apiaceae / Umbelliferae or Brassicaceae / Cruciferae, small genera were defined, whereas groups not subdivided by classical authors remained as larger genera, such as Carex. A number of biological factors also influence the number of species. For instance, the occurrence of apomixis allows the recognition of large numbers of agamospecies, and such taxa have helped to bolster genera such as Ranunculus and Potentilla.
The introduction of infrageneric taxa in the 19th century by botanists including Augustin Pyrame de Candolle allowed the retention of large genera that would otherwise have become unwieldy. E. J. H. Corner believed that studying large genera might enable greater insights into evolutionary biology, and he concentrated his efforts on large tropical genera such as Ficus.

Largest genera

, there are a total of 86 genera of flowering plants with at least 500 species. It is clear that there are other genera with over 500 species, as the work of taxonomists continues. Currently, the number of species included in many genera is very different, so their ranking is subject to changes. The actual number of species is also imprecisely known because of different approaches of taxonomists, and many of the genera have not been the subject of recent monographs. For instance, estimates of the number of species in the orchid genus Pleurothallis range from 1,120 to 2,500. Genera from some other groups of vascular plants, which have similarly large numbers of species, include Selaginella, Asplenium and Cyathea.
File:Astragalusagnicidus.jpg|thumb|Astragalus is the largest flowering plant genus, with more than 3,200 species, including Astragalus agnicidus.|alt=A legume with inflorescences of up to 40 elongated, ivory-coloured flowers, and pinnate leaves with many pairs of leaflets.
File:Bulbophyllumguttulatum24.JPG|thumb|Bulbophyllum is the second largest flowering plant genus, with more than 2,000 species, including Bulbophyllum guttulatum.|alt=Five orchid flowers, each with spotted tepals and a pink labellum.
File:Starr 020925-0087 Psychotria mariniana.jpg|thumb|Psychotria is the third largest flowering plant genus, with more than 1,900 species, including Psychotria mariniana.|alt=A shrub with large, leathery, simple leaves, and bearing clusters of round, green fruit.
File:Euphorbia amygdaloides - Berlin Botanical Garden - IMG 8500.JPG|thumb|Euphorbia is the fourth largest flowering plant genus, with more than 1,800 species, including Euphorbia amygdaloides.|alt=A group of unbranched herbs grow beside a plant label. The upper leaves and bracts grade from green to yellow.
File:Carex pilulifera habitus.jpeg|thumb|Carex is the fifth largest flowering plant genus, with more than 1,700 species, including Carex pilulifera.|alt=Several small, grass-like plants with thin leaves, each with a stalk bearing a cluster of small round fruits.
RankGenusSpeciesFamilySpecies list
1Astragalus 3,239FabaceaeList of Astragalus species
2Taraxacum 2,387AsteraceaeList of Taraxacum species
3Hieracium 2,349AsteraceaeList of Hieracium species
4Carex 2,328CyperaceaeList of Carex species
5Bulbophyllum 2,190OrchidaceaeList of Bulbophyllum species
6Piper 2,169PiperaceaeList of Piper species
7Euphorbia 2,157EuphorbiaceaeList of Euphorbia species
8Begonia 2,144BegoniaceaeList of Begonia species
9Miconia 1,939MelastomataceaeList of Miconia species
10Epidendrum 1,872OrchidaceaeList of Epidendrum species
11Rubus 1,732RosaceaeList of Rubus species
12Senecio 1,681AsteraceaeList of Senecio species
13Psychotria 1,650RubiaceaeList of Psychotria species
14Dendrobium 1,647OrchidaceaeList of Dendrobium species
15Ranunculus 1,616RanunculaceaeList of Ranunculus species
16Peperomia 1,384PiperaceaeList of Peperomia species
17Anthurium 1,346AraceaeList of Anthurium species
18Stelis 1,338OrchidaceaeList of Stelis species
19Eugenia 1,284MyrtaceaeList of Eugenia species
20Solanum 1,238SolanaceaeList of Solanum species
21Syzygium 1,236MyrtaceaeList of Syzygium species
22Acacia 1,234FabaceaeList of Acacia species
23Rhododendron 1,195EricaceaeList of Rhododendron species
24Lepanthes 1,189OrchidaceaeList of Lepanthes species
25Croton 1,178EuphorbiaceaeList of Croton species
26Salvia 1,049LamiaceaeList of Salvia species
27Phyllanthus 1,025PhyllanthaceaeList of Phyllanthus species
28Impatiens 1,002BalsaminaceaeList of Impatiens species
29Justicia 983AcanthaceaeList of Justicia species
30Allium 970AmaryllidaceaeList of Allium species
31Cyperus 961CyperaceaeList of Cyperus species
32Habenaria 908OrchidaceaeList of Habenaria species
33Ficus 876MoraceaeList of Ficus species
34Eucalyptus 865MyrtaceaeList of Eucalyptus species
35Erica 853EricaceaeList of Erica species
36Myrcia 820MyrtaceaeList of Myrcia species
37Centaurea 793AsteraceaeList of Centaurea species
38Diospyros 787EbenaceaeList of Diospyros species
39Indigofera 787FabaceaeList of Indigofera species
40Vaccinium 785EricaceaeList of Vaccinium species
41Crotalaria 760FabaceaeList of Crotalaria species
42Cyrtandra 749GesneriaceaeList of Cyrtandra species
43Alchemilla 734RosaceaeList of Alchemilla species
44Viola 727ViolaceaeList of Viola species
45Verbascum 724ScrophulariaceaeList of Verbascum species
46Vernonia 723AsteraceaeList of Vernonia species
47Ardisia 721PrimulaceaeList of Ardisia species
48Pedicularis 711OrobanchaceaeList of Pedicularis species
49Cousinia 709AsteraceaeList of Cousinia species
50Mimosa 689FabaceaeList of Mimosa species
51Palicourea 689Rubiaceae
52Festuca 686PoaceaeList of Festuca species
53Tillandsia 678BromeliaceaeList of Tillandsia species
54Galium 678RubiaceaeList of Galium species
55Polygala 673PolygalaceaeList of Polygala species
56Maxillaria 658OrchidaceaeList of Maxillaria species
57Masdevallia 656OrchidaceaeList of Masdevallia species
58Oxytropis 654FabaceaeList of Oxytropis species
59Elatostema 652Urticaceae
60Lupinus 650FabaceaeList of Lupinus species
61Dioscorea 649Dioscoreaceae
62Salix 629SalicaceaeList of Salix species
63Berberis 628Berberidaceae-
64Quercus 627FagaceaeList of Quercus species
65Aloe 623AsphodelaceaeList of Aloe species
66Ipomoea 621ConvolvulaceaeList of Ipomoea species
67Poa 617PoaceaeList of Poa species
68Pilea 613UrticaceaeList of Pilea species
69Pandanus 605PandanaceaeList of Pandanus species
70Ilex 596AquifoliaceaeList of Ilex species
71Coelogyne 595OrchidaceaeList of Coelogyne species
72Helichrysum 580AsteraceaeList of Helichrysum species
73Philodendron 569AraceaeList of Philodendron species
74Ixora 566RubiaceaeList of Ixora species
75Passiflora 561PassifloraceaeList of Passiflora species
76Saxifraga 561SaxifragaceaeList of Saxifraga species
77Oxalis 557OxalidaceaeList of Oxalis species
78Pleurothallis 556OrchidaceaeList of Pleurothallis species
79Primula 553PrimulaceaeList of Primula species
80Ocotea 545LauraceaeList of Ocotea species
81Corydalis 528PapaveraceaeList of Corydalis species
82Aristolochia 524AristolochiaceaeList of Aristolochia species
83 Artemisia 523AsteraceaeList of Artemisia species
84Hypericum 517HypericaceaeList of Hypericum species
85Potentilla 505RosaceaeList of Potentilla species
86Delphinium 503RanunculaceaeList of Delphinium species