''Equilabium'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s in the family

Lamiaceae The Lamiaceae ( ) or Labiatae are a 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, mint, rosemary, sage, savory ...

. It was split off from the genus ''

Plectranthus ''Plectranthus'' is a genus of about 85 species of flowering plants from the sage family, Lamiaceae, found mostly in southern and tropical Africa and Madagascar. Common names include spur-flower. ''Plectranthus'' species are herbaceous perennia ...

'' 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 list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...

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 t ...

or soft-wooded

shrub A shrub (often also called a 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 ...

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

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

. The leaves are opposite. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

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. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...

). 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 The term ''sepalum'' was coined b ...

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

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

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

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s, whose filaments are not fused together. The style is divided into two parts (bifid). The nutlets are ovoid. ''Equilabium'' and ''

'' species are distinguished from ''

Coleus ''Coleus'' is a genus of annual or perennial herbs or shrubs, sometimes succulent, sometimes with a fleshy or tuberous rootstock, found in the Old World tropics and subtropics. The relationship among the genera ''Coleus'', '' Solenostemon'' and ...

'' by having the stem (

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

) of the

calyx Calyx or calyce (plural "calyces"), from the Latin ''calix'' which itself comes from the Ancient Greek ''κάλυξ'' (''kálux'') meaning "husk" or "pod", may refer to: Biology * Calyx (anatomy), collective name for several cup-like structures ...

attached symmetrically to the base of the calyx tube, rather than opposite the upper lip, and having the

corolla Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name * Corolla (headgear), an ancient headdress in the form of a circlet or crown * ''Corolla'' (gastropod), a genus of moll ...

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 ''

'', which was discovered not to be

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

. Only the names of the genus and the

type species In 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 species that contains the biological type specimen ...

, ''

Equilabium laxiflorum ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian subc ...

'', 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 ''

'' revived. In the version below, the three genera accepted in these studies that were formerly included in a broad circumscription of ''Plectranthus'' are highlighted.

Species

Paton et al. (2019) list 42 species: *''

Equilabium acaule ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian s ...

'' (Brummitt & Seyani) Mwany., Culham & A.J.Paton (syn. ''Plectranthus acaulis'') – Malawi to Zambia (Nyika Plateau) *''

Equilabium agnewii ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian s ...

'' (Lukhoba & A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus agnewii'') – E. Tropical Africa *''

Equilabium annuum ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian s ...

'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus annuus'') – S. Tanzania to Mozambique *''

Equilabium caespitosum ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian subc ...

'' (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 ''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 phylogenetic study. Most species are native to Africa, with two found in the Indian sub ...

'' (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 *''

'' (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 ''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 ...

'' (A.J.Paton) Mwany. & A.J.Paton (syn. ''Plectranthus scopulicola'') – Tanzania (W. Usambara Mts.) *'' Equilabium selukwense'' (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