''Equilabium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family

Lamiaceae The Lamiaceae ( ) or Labiatae are a family (biology), family of flowering plants commonly known as the mint, deadnettle, or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil (herb), ba ...

. It was split off from the genus '' Plectranthus'' in 2018 as the result of a

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study. Most species are native to Africa, with two found in the

Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...

Description

Species of ''Equilabium'' are

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

or soft-wooded

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s, rarely woody shrubs. The herbaceous species may be annual or

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

. The leaves are opposite. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s are " thryses" – compound structures in which the flowers are arranged on secondary branches. Individual flowers have stalks (

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branch ...

). The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s form a two-lipped funnel shape, the upper lip having four lobes, the lower lip one lobe. The

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s form a two-lipped tube, with an S-shaped basal portion. There are four

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s, whose filaments are not fused together. The style is divided into two parts (bifid). The nutlets are ovoid. ''Equilabium'' and '' Plectranthus'' species are distinguished from '' Coleus'' by having the stem ( pedicel) of the calyx attached symmetrically to the base of the calyx tube, rather than opposite the upper lip, and having the corolla lobes more or less equal in length. ''Equilabium'' species can be distinguished from ''Plectranthus'' by the truncated shape of the throat of the calyx and by the usually S-shaped tube of the corolla, which is parallel-sided at the base.

Taxonomy

The genus ''Equilabium'' was first described in 2018 as the result of a

study. ''Equilabium'' was split off from the genus '' Plectranthus'', which was discovered not to be

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. Only the names of the genus and the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, '' Equilabium laxiflorum'', were formally published at the time. The names of 41 more species were published in 2019.

Phylogeny

In 2019, Paton et al. published a summary cladogram for the subtribe Plectranthinae, based on an earlier 2018 study. The new genus ''Equilabium'' was established and '' Coleus'' revived. In the version below, the three genera accepted in these studies that were formerly included in a broad

circumscription Circumscription may refer to: * Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthr ...

of ''Plectranthus'' are highlighted.

Species

Paton et al. (2019) list 42 species: *'' Equilabium acaule'' (Brummitt & Seyani) Mwany., Culham & A.J.Paton (syn. ''Plectranthus acaulis'') – Malawi to Zambia (Nyika Plateau) *'' Equilabium agnewii'' (Lukhoba & A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus agnewii'') – E. Tropical Africa *'' Equilabium annuum'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus annuus'') – S. Tanzania to Mozambique *'' Equilabium caespitosum'' (Lukhoba & A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus caespitosus'') – Kenya to N. Tanzania *'' Equilabium candelabriforme'' (Launert) Mwany. & A.J.Paton (syn. ''Plectranthus candelabriformis'') – Tanzania to N. Namibia *'' Equilabium cinereum'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus cinereus'') – Kenya to Tanzania *'' Equilabium dissectum'' (Brenan) Mwany. & A.J.Paton (syn. ''Plectranthus dissectus'') – S. Malawi *'' Equilabium dolomiticum'' (Codd) Mwany. & A.J.Paton (syn. ''Plectranthus dolomiticus'') – Zimbabwe to Limpopo *'' Equilabium equisetiforme'' (E.A.Bruce) Mwany. & A.J.Paton (syn. ''Coleus equisetiformis'') – Tanzania to N. Zambia *'' Equilabium flaccidum'' (Vatke) Mwany. & A.J.Paton (syns ''Coleus flaccidus'', ''Plectranthus flaccidus'') – S. Somalia to Mozambique, Comoros *'' Equilabium glandulosum'' (Hook. f.) Mwany. & A.J.Paton (syn. ''Plectranthus glandulosus'') – Widespread in Tropical Africa *'' Equilabium goetzei'' (Gürke) Mwany. & A.J.Paton (syn. ''Plectranthus goetzei'') – SW. Tanzania to Zambia *'' Equilabium gracile'' (Suess.) Mwany. & A.J.Paton (syn. ''Plectranthus gracilis'') – S. Tanzania to S. Tropical Africa *'' Equilabium intrusum'' (Briq.) Mwany. & A.J.Paton (syn. ''Plectranthus intrusus'') – Democratic Republic of the Congo *'' Equilabium janthinothryx'' (Lebrun & L. Touss) Mwany. & A.J.Paton (syn. ''Plectranthus janthinothryx'') – Democratic Republic of the Congo and Uganda *'' Equilabium jebel-marrae'' (Wickens & B.Mathew) A.J.Paton (syn. ''Plectranthus jebel-marrae'') – Sudan *'' Equilabium kamerunense'' (Gürke) Mwany. & A.J.Paton (syn. ''Plectranthus kamerunensis'') – Nigeria to Cameroon, E. Tropical Africa *'' Equilabium laxiflorum'' (Benth.) Mwany. & A.J.Paton (syn. ''Plectranthus laxiflorus'') – Ethiopia to South Africa *'' Equilabium longipes'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus longipes'') – Eritrea to Rwanda and Tanzania *'' Equilabium mafiense'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus mafiensis'') – Tanzania (Mafia I.) *'' Equilabium masukense'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus masukensis'') – Kenya to N. Zambia *'' Equilabium megafolium'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus megafolius'') – Tanzania (type) *'' Equilabium molle'' (Aiton) Mwany. & A.J.Paton (syn. ''Ocimum molle'', ''Plectranthus mollis'') – Indian Subcontinent to N. Myanmar *'' Equilabium orbiculare'' (Gürke) Mwany. & A.J.Paton (syn. ''Plectranthus orbicularis'') – E. Tanzania (incl. Zanzibar, Pemba) *'' Equilabium parvum'' (Oliv.) Mwany. & A.J.Paton (syn. ''Plectranthus parvus'') – Uganda to N. Zambia *'' Equilabium pauciflorum'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus pauciflorus'') – Democratic Republic of the Congo, East Africa, Zambia *'' Equilabium petiolare'' (Benth.) Mwany. & A.J.Paton (syn. ''Plectranthus petiolaris'') – S. Mozambique to South Africa *'' Equilabium pinetorum'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus pinetorum'') – Malawi and E. Zimbabwe *'' Equilabium pubescens'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus pubescens'') – SW. Tanzania to Mozambique *'' Equilabium pulcherissimum'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus pulcherissimus'') – Democratic Republic of the Congo and Zambia *'' Equilabium radiatum'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus radiatus'') – S. Tanzania *'' Equilabium rungwense'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus rungwensis'') – Tanzania (Mt. Rungwe) *'' Equilabium scopulicola'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus scopulicola'') – Tanzania (W. Usambara Mts.) *''

Equilabium selukwense ''Equilabium'' is a genus of flowering plants in the family Lamiaceae. It was split off from the genus ''Plectranthus'' in 2018 as the result of a Molecular phylogenetics, molecular phylogenetic study. Most species are native to Africa, with two ...

'' (N.E.Br.) Mwany. & A.J.Paton (syn. ''Plectranthus selukwensis'') – Zambia to Zimbabwe *'' Equilabium spananthum'' (A.J.Paton, Friis & Sebsebe) A.J.Paton (syn. ''Plectranthus spananthus'') – Ethiopia *'' Equilabium stenophyllum'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus stenophyllus'') – S. Tanzania to S. Tropical Africa *'' Equilabium stenosiphon'' (Baker) Mwany. & A.J.Paton (syn. ''Plectranthus stenosiphon'') – S. Malawi to C. Mozambique and Zimbabwe *'' Equilabium stoltzii'' (Gilli) Mwany. & A.J.Paton (syn. ''Plectranthus stolzii'') – SW. Tanzania to N. Malawi *'' Equilabium subincisum'' (Benth.) Mwany., Smitha & A.J.Paton (syn. ''Plectranthus subincisus'') – S. India, Sri Lanka? *'' Equilabium vesiculare'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus vesicularis'') – Tanzania to N. Mozambique *'' Equilabium viphyense'' (Brummitt & Seyani) Mwany., Culham & A.J.Paton (syn. ''Plectranthus viphyensis'') – Tanzania to S. Tropical Africa *'' Equilabium wollastonii'' (S.Moore) Mwany. & A.J. Paton (syn. ''Plectranthus wollastonii'') – E. Central Tropical Africa to S. Kenya.

References

{{Taxonbar, from=Q93760161 Lamiaceae Lamiaceae genera