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The families of flowering plants

L. Watson and M.J. Dallwitz

Labiatae Juss.

Alternatively Labiaceae Dulac, Labiataceae Boerl., Lamiaceae Lindl. (nom. altern.).

Including Menthaceae Burnett, Nepetaceae Horan., Salazariaceae F. Barkley, Scutellariaceae Caruel; excluding Tetrachondraceae.

Habit and leaf form. Herbs (usually), or shrubs (sometimes ericoid), or trees (rarely), or lianas (rarely); characteristically bearing essential oils (the crushed foliage either aromatic or foetid, with taxonomic predictability). Plants succulent (rarely, e.g. some Coleus spp.), or non-succulent (mostly). The herbs annual to perennial; without conspicuous aggregations of leaves. Self supporting (usually), or climbing (occasionally). Helophytic, or mesophytic, or xerophytic. Leaves opposite (decussate on the usually square stem), or whorled; when whorled, 3–10 per whorl (e.g. Dysophylla); flat, or folded, or rolled, or terete; ‘herbaceous’ (mostly), or leathery, or fleshy; petiolate to sessile; aromatic, or foetid, or without marked odour (very rarely); simple, or compound; epulvinate; when compound, pinnate. Lamina dissected, or entire; when dissected, pinnatifid, or palmatifid; one-veined, or pinnately veined, or palmately veined; cross-venulate; cordate to cuneate at the base, or rounded at the base. Leaves exstipulate. Lamina margins entire, or crenate, or serrate. Leaf development not ‘graminaceous’. Domatia occurring in the family (found in Cuminia); manifested as pockets.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial, or centric. Hydathodes present (ocasionally), or absent. Abaxial epidermis not papillose. Stomata predominantly diacytic, or anomocytic, or anisocytic, or anomocytic and anisocytic. Hairs usually present (represented by numerous kinds, see illustrations); usually eglandular and glandular (the latter usually conspicuous); unicellular, or multicellular. Unicellular hairs branched, or simple. Multicellular hairs uniseriate, or multiseriate; branched, or simple. Complex hairs present, or absent; when present, stellate. Urticating hairs absent. Adaxial hypodermis absent. The mesophyll containing crystals, or without crystals. The crystals when present, usually solitary-prismatic (in the form of small rods or octohedra, often many per cell), or druses (rather rarely). Midrib conspicuous. Main veins embedded. Minor leaf veins without phloem transfer cells (8 genera).

Axial (stem, wood) anatomy. Young stems usually tetragonal; with solid internodes, or with spongy internodes, or with hollow internodes. Pith with crystalline inclusions, or without crystalline inclusions. Secretory cavities absent. Cork cambium present; initially deep-seated, or initially superficial. Nodes unilacunar (with 1 or 2 traces). Primary vascular tissues at first comprising a ring of bundles (four, one in each corner of the stem), or in a cylinder, without separate bundles (subsequently); collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide, or mixed wide and narrow, or narrow.

The wood semi-ring porous, or diffuse porous. The vessels small (sometimes extremely so); solitary (rarely, e.g. Hoslundia), or radially paired, or in radial multiples, or clustered, or in tangential arcs (typically in small multiples or groups that are arranged in tangential lines). The vessel end-walls simple. The vessels with vestured pits (rarely), or without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem without fibre tracheids; with libriform fibres; at least sometimes including septate fibres, or without septate fibres. The fibres without spiral thickening. The parenchyma paratracheal (rather sparse to very sparse). ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Plants hermaphrodite, or dioecious, or gynodioecious (fairly commonly), or polygamomonoecious (rarely). Pollination entomophilous, or ornithophilous; usually via hymenoptera, or via lepidoptera, or via diptera.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in verticils (usually, these usually formed from axillary pairs of dichasial or circinate cymes), or in heads, or in spikes, or in cymes, or in panicles. The ultimate inflorescence units cymose. Inflorescences terminal, or axillary. Flowers minute to medium-sized; somewhat irregular to very irregular; zygomorphic; resupinate (by torsion of pedicel or (e.g. in Teucrium, Ajuga) the corolla tube), or not resupinate. The floral irregularity involving the perianth and involving the androecium (though sometimes not the calyx). Flowers cyclic; tetracyclic. Floral receptacle developing a gynophore, or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk often present, or absent.

Perianth with distinct calyx and corolla; 4–10; 2 whorled; isomerous, or anisomerous (or only dubiously interpretable). Calyx 2, or 3, or 4, or 5 (basically 5, but often with the bilabiate condition superimposed, and 2-lobed in e.g. Prostanthera, 3-lobed in Melittis, 4-lobed in e.g. Preslia); 1 whorled; variously gamosepalous; entire (occasionally), or blunt-lobed, or toothed. Calyx lobes markedly shorter than the tube to markedly longer than the tube. Calyx campanulate, or funnel-shaped, or tubular; unequal but not bilabiate (one-lipped), or bilabiate, or regular; persistent; imbricate, or open in bud (commonly); (when K 5) with the median member posterior. Corolla more or less disguisedly 5 (usually with no clear indication of individual petals — commonly with five lobes, but usually with the bilabiate condition superimposed, and the five lobes variously secondarily lobed, reduced or suppressed), or 4 (occasionally, ostensibly, e.g. Mentha); 1 whorled; gamopetalous; imbricate; bilabiate (usually, the lower lip typically three-lobed, the upper commonly bilobed or emarginate but sometimes entire or three or four lobed), or unequal but not bilabiate (e.g. Teucrium, where the upper lip is suppressed), or regular (rarely, almost, as in Mentha); plain, or with contrasting markings.

Androecium 2, or 4(–5) (usually). Androecial members adnate; all equal, or markedly unequal; usually free of one another, or coherent (in Coleus); in Coleus 1 adelphous; 1 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1 (posterior), or 2 (the posterior pair, or the anterior pair); in the same series as the fertile stamens; representing the posterior median member, or the posterior-lateral pair, or the anterior-lateral pair. Fertile stamens representing the posterior-lateral pair, or the anterior-lateral pair, or the posterior-lateral pair and the anterior-lateral pair (commonly). Stamens 2, or 4; inserted near the base of the corolla tube (rarely, e.g. Teucrium), or midway down the corolla tube, or in the throat of the corolla tube (and sometimes the pairs attached at different levels); didynamous (usually, with the anterior pair longer), or not didynamous, not tetradynamous; reduced in number relative to the adjacent perianth (at least theoretically); oppositisepalous. Anthers connivent (in pairs, commonly), or separate from one another; dorsifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse; unilocular to bilocular; tetrasporangiate; appendaged, or unappendaged. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or decussate. Anther wall initially with one middle layer; of the ‘dicot’ type. Tapetum glandular. Pollen monosiphonous; shed as single grains. Pollen grains aperturate; 3 aperturate, or 4 aperturate, or 6 aperturate; colpate, or colporate; 2-celled (in 52 genera), or 3-celled (in 70 genera), or 2-celled and 3-celled (with both states in 3 genera).

Gynoecium 2 carpelled (but the carpels deeply lobed to mimic G4). Carpels reduced in number relative to the perianth. The pistil 4 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 2 locular (originally, but usually becoming ostensibly four by intrusions of the ovary wall constituting ‘false septa’). Locules secondarily divided by ‘false septa’. Gynoecium median. Styles 1; when ‘apical’, from a depression at the top of the ovary (then the ovary deeply lobed); ‘gynobasic’ (usually), or apical. Stigmas 2, or 1 (by reduction); 2 lobed; dry type; papillate; Group II type. Placentation basal. Ovules 2 per locule, or 1 per locule (two per original loculus, but one per locellus); ascending; apotropous; with ventral raphe (and the micropyle directed downwards); non-arillate; anatropous, or hemianatropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; proliferating (rarely, e.g. Physostegia), or not proliferating; ephemeral, or persistent. Synergids commonly hooked. Endosperm formation cellular. Endosperm haustoria present; usually chalazal and micropylar (the latter aggressive). Embryogeny nearly always onagrad (rarely asterad).

Fruit usually non-fleshy, or fleshy (rarely); more or less a schizocarp (except perhaps in Eichlerago (= Prostanthera), where it is said to be hard, indehiscent and non-schizocarpic). Mericarps (2–)4; comprising nutlets (typically of four nutlets, distinct or cohering pairwise, enclosed in the persistent calyx), or comprising drupelets (rarely, e.g. Prasieae). Seeds endospermic to non-endospermic (the scant, fleshy endosperm often absorbed by the developing embryo). Embryo well differentiated (with a downward-pointing radicle, by contrast with Boraginaceae). Cotyledons 2; flat. Embryo achlorophyllous (16/23); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3 and CAM. C3 physiology recorded directly in Coleus, Hedeoma, Hyptis, Leonurus, Leucas, Lycopus, Marrubium, Mentha, Monarda, Perilla, Prunella, Salvia, Stachys, Teucrium, Thymus. CAM recorded directly in Plectranthus. Anatomy non-C4 type (Hedeoma, Lycopus, Marrubium, Mentha, Perovskia, Phlomis, Salvia, Stachys, Teucrium, Ziziphora). Sugars transported as sugar alcohols + oligosaccharides + sucrose (in Rosmarinus, Salvia). Cyanogenic (rarely), or not cyanogenic. Alkaloids present (commonly), or absent. Verbascosides detected (in 6 genera, absent from Lamium album). Cornoside detected (Teucrium). Iridoids detected (commonly); ‘Route II’ type (normal and decarb.). Saponins/sapogenins absent. Proanthocyanidins absent. Flavonols mostly absent. Ellagic acid absent (15 species, 14 genera). Ursolic acid present. Aluminium accumulation not found. Sieve-tube plastids S-type.

Geography, cytology. Frigid zone to tropical. Cosmopolitan. X = 5–11(+).

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Lamiiflorae; Lamiales. Cronquist’s Subclass Asteridae; Lamiales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Lamiales.

Species about 3500. Genera about 210; Acanthomintha, Achyrospermum, Acinos, Acrocephalus, Acrotome, Acrymia, Aeollanthus, Agastache, Ajuga, Ajugoides, Alajja, Alvesia, Amethystea, Anisochilus, Anisomeles, Antonina, Asterohyptis, Ballota, Basilicum, Becium, Benguellia, Blephilia, Bostrychanthera, Bovonia, Brazoria, Bystropogon, Calamintha, Capitanopsis, Capitanya, Catoferia, Cedronella, Ceratanthus, Chamaesphacos, Chaunostoma, Chelonopsis, Cleonia, Clinopodium, Colebrookia, Coleus(=Plectranthus),, Collinsonia, Colquhounia, Comanthosphace, Conradina, Craniotome, Cuminia, Cunila, Cyclotrichium, Cymaria, Dauphinea, Dicerandra, Dorystaechas, Dracocephalum, Drepanocaryum, Eichlerago, Elsholtzia, Endostemon, Englerastrum, Eremostachys, Eriope, Eriiophyton, Eriopidion, Eriothymus, Erythrochlamys, Eurysolen, Fuerstia, Galeopsis, Geniosporum, Glechoma, Glechon, Gomphostemma, Gontscharovia, Hanceola, Haplostachys, Haumaniastrum, Hedeoma, Hemiandra, Hemigenia, Hemizygia, Hesperozygis, Heterolamium, Hoehnea, Holocheila, Holostylon, Horminium, Hoslundia, Hymenocrater, Hypenia, Hypogomphia, Hyptidendron, Hyptis, Hyssopus, Isodictyophorus, Isodon, Isoleucas, Keiskea, Kinostemon, Kudrjaschevia, Kurzamra, Lagochilus, Lagopsis, Lallemantia, Lamiophlomis, Lamium, Lavandula, Leocus, Leonotis, Leonurus, Lepechinia, Leucas, Leucosceptrum, Limniboza, Lophanthus, Loxocalyx, Lycopus, Macbridea, Marmoritis, Marrubium, Marsypianthes, Meehania, Melissa, Melittis, Mentha, Meriandra, Mesona, Metastachydium, Microcorys, Micromeria, Microtoena, Minthostachys, Moluccella, Monarda, Monardella, Mosla, Neoeplingia, Neohyptis, Nepeta, Neustruevia, Nosema, Notochaete, Ocimum, Octomeron, Ombrocharis, Origanum, Orthosiphon, Otostegia, Panzerina, Paraeremostachys, Paralamium, Paraphlomis, Peltodon, Pentapleura, Perilla, Periloma (Scutellaria), Perovskia, Perrierastrum, Phlomis, Phlomoides, Phyllostegia, Physostegia, Piloblephis, Pitardia, Platostoma, Plectranthus, Pogogyne, Pogostemon, Poliomintha, Prasium, Prostanthera, Prunella, Pseuderemostachys, Puntia, Pycnanthemum, Pycnostachys, Renschia, Rhabdocaulon, Raphidion, Rhododon, Rosmarinus, Rostrinucula, Roylea, Rubiteucris, Sabaudia, Saccocalyx, Salvia, Satureja, Schizonepeta, Scutellaria, Sideritis, Siphocranion, Skapanthus, Solenostemon, Stachyopsis, Stachys, Stenogyne, Sulaimania, Suzukia, Symphostemon, Synandra, Syncolostemon, Tetradenia, Teucrium, Thorncroftia, Thuspeinanta, Thymbra, Thymus, Tinnea, Trichostema, Wenchengia, Westringia, Wiedemannia, Wrixonia, Zataria, Zhumeria, Ziziphora.

General remarks. Junell (1934), Erdtman (1945), Wunderlich (1967) and El-Gazzar and Watson (1970), all expressed dissatisfaction with traditional classifications of Labiatae, and with the circumscription of Labiatae relative to that of Verbenaceae sensu lato, based on very extensive comparative anatomical, palynological, phytochemical, morphological and host/parasite surveys. Their ideas, extended by assorted morphological-cladistic and molecular studies starting with Cantino et al. (1992), have now been implemented formally in the shape of radically revised family circumscriptions. Practical implementation of these awaits the re-organization of the descriptive data into adequately detailed comparative descriptions .....

Economic uses, etc. The source, par excellence, of aromatic and antibiotic essential oils for the pharmaceutical and cosmetics industries (species of Salvia, Lavandula, Rosmarinus, Mentha, Marrubium, Pogostemon etc.), and of aromatic/flavoursome pot herbs (Salvia, Origanum, Thymus, Ocimum, Satureia etc.). Many are cultivated as ornamentals (Salvia, Ajuga, Physostegia, Monarda, Scutellaria, Nepeta, Teucrium, Stachys, Phlomis etc.).


I know a bank wheron the wild thyme blows
(‘Midsummer Night’s Dream’, ii., 2)

Rosemarie is for remembrance
Between us daie and night,
Wishing that I might always have
You present in my sight
(from the 1566 songbook, ‘A handefull of Pleasant Delites’)

The several chairs of order, look you, scour
With juice of balm, and every precious flower
(Melissa officinalis - ‘Merry Wives’, v., 2)

And there upon the sod below,
Ground Ivy’s purple blossoms show,
Like helmet of crusader knight,
Its anther’s cross-like form of white
(Bishop Mant, quoted by Ann Pratt, ‘Wild Flowers’ (1857) - of Glechoma hederacea)

And there, with whorls encircling graced,
Of white, and purple-tinted red,
The Harmless Nettle’s helmet head;
Less apt with fragrance to delight
The smell, than please the curious sight
(Bishop Mant, quoted by Ann Pratt, ‘Wild Flowers’ (1857) - of Lamium album)

Illustrations. • Technical details: Plectranthus. • Technical details: Salvia. • Technical details: Lamium, Mentha, Salvia, Scutellaria, Ajuga, Rosmarinus, Prunella. • ‘Group A’: Stachys, Lamium (B. Ent. compilation, 1824–35). • ‘Group A’: Galeobdolon, Galeopsis, Ballota (B. Ent. compilation, 1824–35). • ‘Group A’: Ajuga, Scutellaria (B. Ent. compilation, 1824–35). • ‘Group A’: Teucrium, Betonica (B. Ent. compilation, 1824–35). • ‘Group B’: Prunella, Nepeta, Glechoma, Salvia (B. Ent. compilation, 1824–35). • ‘Group B’: Mentha (B. Ent. compilation, 1824–35). • ‘Group B’: Origanum, Cliniopodium, Lycopus (B. Ent. compilation, 1824–35). • Agastache anisata: Bot. Reg. 1282, 1829. • Ajuga chamaepitys, A. pyramidalis and A. reptans: Eng. Bot. 1088, 1089 and 1090, 1867. • Becium bicolor: Bot. Reg. 29 (15), 1843. • Clinopodium calamintha: as Calamintha nepeta, Eng. Bot. 1049, 1867. • Clinopodium menthifolium: as Calamintha menthifolium, Eng. Bot. 1050, 1867. • Clinopodium menthifolium: as Calamintha sylvatica, Eng. Bot. 1052, 1867. • Clinopodium vulgare: as Calamintha clinopodium, Eng. Bot. 1047, 1867. • Eriope macrostachya: Hook. Ic. Pl. 5–6 (1842–3). • Galeopsis segetum and G. speciosa: as G.ochroleuca and G. versicolor, Eng. Bot. 1076 and 1077, 1867. • Galeopsis angustifolia, G. bifida and G. tetrahit: Eng. Bot. 1074, 1078 and 1079, 1867. • Glechoma hederacea: as Nepeta glechoma, Eng. Bot. 1055, 1867. • Hypenia salzmannii, as Hyptis: Hook Ic. Pl. 5–6 (1842–3). • Hyptis verticillata: Hook. Ic. Pl. 5–6 (1842–3). • Lamiastrum galeobdolon: as Lamium galeobdolon, Eng. Bot. 1087, 1867. • Isodon scrophularioides, as Plectranthus: Hook. Ic. Pl. 5–6 (1842–3). • Lamium album: Eng. Bot. 1086, 1867. • Lamium amplexicaule and L. confertum (as L. intermedium): Eng. Bot. 1081 and 1082, 1867. • Lamium hybridum (as L. incisum), L. maculatum and L. purpureum: Eng. Bot. 1083, 1084 and 1085, 1867. • Leonurus cardiaca: Eng. Bot. 1080, 1867. • Lepechinia spicata: Bot. Reg. 1292. • Lycopus europaeus: Eng. Bot. 1019, 1867. • Marrubium vulgare: Eng. Bot. 1064, 1867. • Marsypianthes chamaedrys, as M. hyptoides: Hook. Ic. Pl. 5–6 (1842–3). • Melissa officinalis: Eng. Bot. 1053, 1867. • Melittis melissophyllum, and var.: Eng. Bot. 1061 and 1062, 1867. • Mentha arvensis: Eng. Bot. 1038, 1867. • Mentha “crispa”: Eng. Bot. 1028, 1867. • Mentha longifolia: as M. sylvestris, Eng. Bot. 1024, 1867. • Mentha x piperita: Eng. Bot. 1024, 1867. • Mentha cf. x piperita: as M. citrata, Eng. Bot. 1029, 1867. • Mentha pulegium var. decumbens: Eng. Bot. 1041, 1867. • Mentha cf. x smithiana: as M. rubra, Eng. Bot. 1033, 1867. • Mentha suaveolens: as M. rotundifolia, Eng. Bot. 1020, 1867. • Moluccella spinosa: Bot. Reg. 1244, 1829. • Nepeta cataria: Eng. Bot. 1054, 1867. • Origanum vulgare: Eng. Bot. 1045, 1867. • Orthosiphon rubicundus: Hook. Ic. Pl. 5–6 (1842–3). • Perilomia (Scutellaria) scutellaroides: as P. ocymoides, Bot. Reg. 1394, 1831. • Platostoma coloratum, as Geniosporum strobiliferum: Hook. Ic. Pl. 5–6 (1842–3). • Platostoma hispidum, as Acrocephalus capitatus: Hook. Ic. Pl. 5–6 (1842–3). • Plectranthus amboinicus (as Coleus): R. Wight 2 (1850). • Plectranthus australis, probably = P. parviflorus: Bot. Reg. 1098, 1827. • Prostanthera cuneata: Hooker, Fl. Tasmaniae (1860). • Prostanthera rotundifolia: Hooker, Fl. Tasmaniae (1860). • Prostanthera lasianthos: Bot. Reg. 143, 1817. • Prostanthera violacea: Bot. Reg. 1072, 1827. • Prunella vulgaris: Eng. Bot. 1059, 1867. • Salvia carnosa: as Audibertia incana, Bot. Reg. 1469, 1831. • Salvia grahami: Bot. Reg. 1370, 1830. • Salvia hians: Bot. Reg. 39, 1841. • Salvia patens: Bot. Reg. 1839, 23. • Salvia pratensis: Eng. Bot. 1058, 1867. • Salvia regla: Bot. Reg. 14, 1841. • Salvia tubifera: Bot. Reg. 44, 1841. • Salvia verbenaca: Eng. Bot. 1056, 1867. • Scutellaria minor and S. galericulata: Eng. Bot. 1061 and 1060, 1867. • Sphacele chamaedryoides: as S. campanulata, Bot. Reg. 1382, 1830. • Stachys inflata: Bot. Reg. 1697, 1835. • Stachys annua, Stachys arvensis and Stachys sylvatica: Eng. Bot. 1071, 1072 and 1073, 1867. • Syncolostemon bracteosus, as Ocimum: Hook. Ic. Pl. 5 (1842–3). • Teucrium bicolor: Bot. Reg. 1255, 1829. • Teucrium botrys and T. scorodonia: Eng. Bot. 1091 and 1093, 1867. • Teucrium scordium and T. chamaedrys: Eng. Bot. 1092 and 1094, 1867. • Thymus pulegioides: as T. chamaedrys, Eng. Bot. 1044, 1867. • Thymus serpyllum: Eng. Bot. 1043, 1867. • Westringia brevifolia: Hooker, Fl. Tasmaniae (1860). • Foliar hairs of Lavandula and Stachys (Solereder, 1908). • Foliar hairs of Coleus, Leucas, Notochaete, Phlomis, Salvia and Teucrium, with Verbenaceae and Dicrastylidaceae (El-Gazzar).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 13th March 2017.’.