Neotropical Lamiaceae

Gemma Bramley, Ray Harley and Alan Paton

Royal Botanic Gardens, Kew, UK. 

Description

Trees, shrubs, subshrubs or perennial or annual herbs, [rarely climbers], aromatic or not.  Stems often quadrangular, erect to prostrate, sometimes forming stolons or large or slender rhizomes. Indumentum usually present, of glandular and non-glandular trichomes, often hair-like, rarely scale-like, usually multicellular-uniseriate, simple, branched, dendroid or stellate, sometimes gland-tipped, large-headed subsessile glands rarely absent. Leaves opposite, often decussate, sometimes whorled, very rarely alternate, simple, entire, toothed or lobed, sometimes compound and then digitate, petiolate or sessile, rarely forming a basal rosette, exstipulate. Inflorescence often bracteate, bracts persistent or deciduous, rarely spirally arranged, composed of cymes, bracteolate or not, and often arranged in a terminal, lax or congested indeterminate thyrse which may be paniculate, raceme-like with cymes often 1-flowered, or spike-like, or rarely congested into a capitulum, with or without a distinct involucre of bracteoles, sometimes conspicuous. Flowers hypogynous, usually bisexual, or less often unisexual due to gynodioecy or gynomonoecy, very rarely due to dioecy. Perianth biseriate, sepals 4-5[(--7)], connate, actinomorphic to zygomorphic, sometimes 2-lipped, lobes 2--many, often 5, equal or unequal, rarely obsolete, some lobes often fused, or lips entire, calyx-tube (5--)10--15-nerved, straight or curved, throat hairy or glabrous, calyx often accrescent, rarely inflated or fleshy in fruit. Petals (4--)5(--16) connate, actinomorphic to more often slightly to strongly zygomorphic, often 2-lipped, rarely 1-lipped, lobes (2--)4--5[(--7)], equal or unequal, porrect to patent, one or other lip often concave to galeate, corolla-tube short to elongate, [rarely spurred], often with annulus of hairs or appendaged within, rarely corolla resupinate. Stamens epipetalous, attached within corolla-tube, usually 4 or 2 by abortion and then staminodes often present, or stamens 5[-6], when 4 often didynamous (rarely a fifth, posterior vestigial staminode present), free or rarely monodelphic, filaments short or often elongate, usually exserted from corolla-tube and sometimes long-exserted from corolla; parallel, divergent or ascending and sometimes included within or lying under the posterior corolla-lip, or declinate and then sometimes included within the anterior corolla-lip, anthers usually dithecous, tetrasporangiate or monothecous by abortion, thecae parallel or divergent, occasionally widely separated by an elongate connective, or apically confluent or synthecous, opening by longitudinal slits or rarely by pores. Disc at base of ovary often present, usually fleshy, entire or irregularly or often 4-lobed, anterior lobe sometimes longer than others, nectariferous. Gynoecium 2-carpellate, often 4-locular by intrusion of carpel wall forming "false septum", [or rarely imperfectly 2-locular and free towards apex], ovary usually 4-ovuled, [2-locular ovaries generally with loculi 2-ovuled and 4-locular ovaries with 1 ovule per loculus], ovary entire or lobed, with terminal style, or more often deeply 4-lobed, the loculi often separated and with style gynobasic; style not  persistent or rarely persistent in young fruit (Prostantheroideae), usually with 2 equal or unequal stigma-lobes, rarely entire with 1 stigma-lobe vestigial, or stigma capitate or very rarely 4-lobed. Ovules anatropous to hemianatropous, usually basal or sub-basal, erect, rarely orthotropous, apical, pendulous, borne laterally or submarginally on the placenta, unitegmic, tenuinucellate. Fruit drupaceous, often with pyrenes, or dry, indehiscent, or frequently, four 1-seeded mericarps, sometimes fewer by abortion. Mericarps (nutlets) often with sculptured, tuberculate, hairy or rarely winged pericarp, mucilage cells often present. Seeds albuminous or exalbuminous, epigeal. Embryo straight or bent, investing or spatulate.

Notes on delimitation

  • The traditional division of Verbenaceae and Lamiaceae is far from satisfactory, e.g., Bentham & Hooker in Gen. Pl. 2: 1131-1223 (1876); Baker & Stapf in F.T.A. 5: 273-502 (1900). The delimitation of these families was based on whether the taxa were mostly woody with a terminal or subterminal style (Verbenaceae) or mostly herbaceous with a gynobasic style (Lamiaceae).  This traditional classification is difficult to implement, there being many intermediates, and also it does not represent phylogenetically natural taxa.  A full discussion of the problems with this traditional classification and of the new circumscription of Verbenaceae and Lamiaceae is provided by Harley in Kubitzki, Fam. Gen. Vasc. Pl. 7: 188-190 (2004).
  • The Verbenaceae is now restricted to subfamily Verbenoideae of traditional classifications (e.g. Briquet in Nat. Pflanzenfam. 4, 3a: 132-182 (1895)) which has an indeterminate racemose inflorescence and a salverform corolla with stamens included; whereas in the Lamiaceae the inflorescence is cymose with determinate, usually opposite cymes and the corollas are tubular and usually bilabiate with the stamens usually exserted from the tube, but can be held within the lobes and rarely within the tube. 
  • The cymes in Lamiaceae are arranged usually in opposite pairs along an indeterminate axis, forming a thyrse. In some Lamiaceae the cymes are reduced to single flowers though bracteoles are often present below the flower in these cases, indicating the cymose, rather than racemose, nature of the inflorescence.  These gross morphological differences are supported by anatomical and pollen characters: the Verbenaceae have their ovules attached marginally on the carpel margin, and have thickened pollen exine near the apertures; the Lamiaceae have the ovules attached submarginally and have an unthickened exine. 

Distribution in the Neotropics

The South American Labiate flora, which contains two very large genera, Salvia L. and Hyptis Jacq., but rather few genera in total, falls naturally into three regions: A. Andean; B. Guianan and Brazilian Shields; C Temperate South America.

A. The Andean Labiatae are primarily derived from north temperate genera, and the various groups have many links to Central America, including Mexico.

  • The largest group is Salvia subg. Calosphace Raf. with its Andean centre of diversity linked to a much larger one in Mexico.
  • Scutellaria L., Stachys L. and Clinopodium L. also appear to have been derived from a southern migration from Central America, but have radiated to produce endemic groups, in some cases associated with adaptations to humming-bird pollination.
  • Other Andean Nepetoid genera include the monotypic Obtegomeria Doroszenko & P.D.Cantino from Colombia, related to Clinopodium, Minthostachys (Benth.) Spach, which appears most closely related to the Macaronesian Bystropogon L'Hér., and Lepechinia Willd., which extends to Mexico with one Hawaiian extension.
  • The small Neotropical genus Catoferia (Benth.) Benth. (Nepetoideae, Ocimeae) also links Central and S America, but its closest relatives would seem to be eastern Asiatic members of the Old World subtribe Ociminae, perhaps the genus Orthosiphon Benth. & M.Ashby.
  • The only other member of the subtribe native to the Americas is Ocimum L., which extends from Mexico to South America. One species extends into lowland areas of the Andes.

B. Guianan and Brazilian Shields.

  • This region, including Amazonian and eastern South America, mostly overlying much older geological formations, has a very different flora, dominated by the Nepetoid Ocimeae, subtribe Hyptidinae.
  • This is composed of the large genus Hyptis with about 300 species, and a number of smaller endemic, satellite genera, such as Peltodon Pohl, Rhaphiodon Schauer, Hypenia Mart. ex Benth., Hyptidendron Harley and Eriope Humb. & Bonpl. ex Benth.
  • The primarily Old World genus Ocimum (Nepetoideae: Ocimeae) is represented by several species endemic to the area. It seems probable that Ocimum originally had an Old World tropical origin, perhaps reaching the New World via W Africa in the early Tertiary.
  • A few species of Salvia (Mentheae) reach the mountains of eastern Brazil and extend south into temperate S America.
  • Other endemic genera to be found in this region include Cornutia (Viticoideae) L., Amasonia L.f. and Monochilus (Ajugoideae) Fisch. & C.A.Mey., and more widespread genera such as Vitex L.,  Clerodendrum (Viticoideae) L. and Aegiphila (Ajugoideae) Jacq. The latter, with over 100 species, extends throughout tropical America.

C. Temperate South America.

  • A number of endemic genera occur in this region, belonging to Nepetoideae, tribe Mentheae: Kurzamra Kuntze, Rhabdocaulon (Benth.) Epling, Glechon Spreng. and Hoehnea Epling, while Cunila D.Royen ex L. and Hesperozygis Epling are trans-equatorial, being also represented in Mexico, although this needs confirmation from molecular studies.

D. Northern America and Mexico.

  • This region has quite a large number of endemic genera, both in the west, especially California, as well as in the East.
  • Most of these belong to Tribe Mentheae (Nepetoideae) and include: Monarda L., Monardella Benth., Pycnanthemum Michx., Rhododon Epling, Stachydeoma Small, Pogogyne Benth., Acanthomintha A.Gray, Neoeplingia Ramamoorthy, P.Hiriart Valencia & F.González Medrano and Blephilia Raf. 
  • Endemic Lamioideae include: Warnockia M.W.Turner, Physostegia Benth., Macbridea Raf., Brazoria Engelm. & Gray and Synandra Nutt. Trichostema (Ajugoideae) Gronov. ex L. is a near endemic, extending into the Caribbean.
  • More widespread, species-rich genera represented in the area, include Scutellaria (Scutellarioideae) L., Stachys (Lamioideae), Salvia, Lycopus L. Clinopodium and Hedeoma (Nepetoideae) Pers., the last a New World genus extending into Andean and temperate South America.
  • Of particular interest is Lycopus (Mentheae), with a circum-boreal distribution, but well represented in North America, while Mentha L. and Dracocephalum L., both primarily Old World genera, each have one species native in North America.
  • One or two members of the species-rich genus Clerodendrum (Ajugoideae) L., primarily of the Old World tropics, occur in southern areas.
  • The primarily tropical Viticoideae is represented by Vitex L., which in the New World is confined to the Caribbean and Central America from Mexico southwards, but there are also two genera endemic to the Caribbean: Petitia Jacq. and Pseudocarpidium Millsp.
  • Mention should also be made here of Callicarpa (Incertae sedis) L. This is a mainly Asiatic genus, with a few New World species, especially C. americana L., in the S United States and Mexico, and others in the Caribbean.

Distinguishing characters (always present)

Other important characters

Key differences from similar families

Number of genera


There are 65 genera of Lamiaceae, of which 48 are native and 17 cultivated/introduced:

  • Acanthomintha (A.Gray) A.Gray, Syn. Fl. N. Amer. 2(1): 365 (1878).
    California, NW. Mexico. 1 Species
  • Aegiphila Jacq., Select. Stirp. Amer. Hist.: t. 16 (1763).Mexico to Tropical America 156 Species.
  • Agastache Clayton ex Gronov., Fl. Virgin., ed. 2: 88 (1762).
    C. & E. Asia, N. America. 12 Species
  • Amasonia L.f., Suppl. Pl.: 48 (1782).
    Trop. America. 5 Species 
    Anisomeles  R.Br., Prodr.: 503 (1810).
    1 Species introduced in Neotropics, native to W. Indian Ocean, Trop. & Subtrop. Asia to N. Australia
  • Asterohyptis Epling, Bull. Torrey Bot. Club 60: 17 (1933 publ. 1932).
    Mexico to C. America, Caribbean. 3 Species
  • Ballota L., Sp. Pl.: 582 (1753). 
    1 Species introduced in Neotropics, native to Macaronesia, Europe, Medit. to W. Asia, Mauritania, Chad, S. Africa
  • Callicarpa L., Sp. Pl.: 111 (1753).
    America, W. Indian Ocean to W. Pacific. 31 Species
  • Catoferia (Benth.) Benth. in G.Bentham & J.D.Hooker, Gen. Pl. 2: 1173 (1876).
    Mexico to Colombia. 4 Species
  • Chaunostoma J.D.Sm., Bot. Gaz. 20: 9 (1895).
    SE. Mexico to C. America. 1 Species
  • Clerodendrum L., Sp. Pl.: 637 (1753).
    Trop. & Subtrop. 34 Species
  • Clinopodium L., Sp. Pl.: 587 (1753).
    Temp. & Subtrop. 57 Species
  • Congea Roxb., Pl. Coromandel 3: 90 (1820)
    1 Species introduced in Neotropics, native to India to SC. China and W. Malesia
  • Cornutia Plum. ex L., Sp. Pl.: 628 (1753).
    Mexico to Trop. America. 9 Species
  • Cunila Royen ex L., Syst. Nat. ed. 10, 2: 1359 (1759), nom. cons.
    C. & E. U.S.A. to C. America, Brazil to Argentina. 20 Species
  • Eriope Humb. & Bonpl. ex Benth., Labiat. Gen. Spec.: 142 (1833).
    S. Trop. America. 30 Species
  • Eriothymus (Benth.) Rchb., Handb. Nat. Pfl.-Syst.: 189 (1837).
    SE. Brazil. 1 Species
  • Glechon Spreng., Syst. Veg. 4(2): 227 (1827).
    Brazil to Argentina. 7 Species
  • Gmelina. Sp. Pl.: 626 (1753).
    1 Species introduced in Neotropics, native to  Mascarenes, Trop. & Subtrop. Asia to W. Pacific
  • Hedeoma Pers., Syn. Pl. 2: 131 (1806).
    America. 34 Species
  • Hesperozygis Epling, Repert. Spec. Nov. Regni Veg. Beih. 85: 132 (1936).
    Mexico, Brazil. 7 Species
  • Hoehnea Epling, Repert. Spec. Nov. Regni Veg. Beih. 115: 8 (1939).
    Brazil to Argentina. 4 Species
  • Holmskioldia Retz., Observ. Bot. 6: 31 (1791). 
    1 Species introduced to Neotropics, native to  Indian Subcontinent to Myanmar
  • Hypenia (Mart. ex Benth.) Harley, Bot. J. Linn. Soc. 98: 91 (1988).
    N. South America to Brazil. 24 Species
  • Hyptidendron Harley, Bot. J. Linn. Soc. 98: 90 (1988).
    S. Trop. America. 16 Species
  • Hyptis Jacq., Collectanea 1: 101 (1787).
    Trop. & Subtrop. America, W. Trop. Africa. 289 Species
  • Lamium L., Sp. Pl.: 579 (1753). 2 Species introduced to Neotropics, native to Temp. Eurasia, Macaronesia to Ethiopia
  • Leonotis (Pers.) R.Br., Prodr.: 504 (1810).
    Trop. & S. Africa, Madagascar. 1 Species introduced to Neotropics
  • Leonurus L., Sp. Pl.: 584 (1753).
    Temp. Eurasia. 2 Species introduced to Neotropics
  • Lepechinia Willd., Hort. Berol. 1: 20 (1804).
    SW. U.S.A. to S. America. 37 Species
  • Leucas R.Br.: 504 (1810). 1 Species introduced to Neotropics, native to Africa to NE. Australia
  • Marrubium L., Sp. Pl.: 583 (1753).
    Macaronesia to Temp. Eurasia. 1 Species introduced to Neotropics
  • Marsypianthes Mart. ex Benth., Labiat. Gen. Spec.: 64 (1833).
    Mexico to Trop. America. 6 Species
  • Melissa L., Sp. Pl.: 592 (1753).
    S. Europe to Malesia. 1 Species introduced to Neotropics 
  • Mentha L., Sp. Pl.: 576 (1753).
    Cosmopolitan. 5 Species
  • Micromeria Benth., Edwards's Bot. Reg. 15: t. 1282 (1829).
    Temp. & Subtrop. 3 Species
  • Mintostachys (Benth.) Spach, Hist. Nat. Vég. 9: 164 (1840).
    S. Trop. America. 11 Species
  • Moluccella L., Sp. Pl.: 587 (1753).
    Medit. to C. Asia. 1 Species (cultivated/introduced)
  • Monochilus Fisch. & C.A.Mey., Index Seminum (LE) 1: 34 (1835).
    Brazil. 84. 2 Species
  • Neoeplingia Ramamoorthy, Hiriart & Medrano, Bol. Soc. Bot. México 43: 61 (1982).
    Mexico. 79. 1 Species
  • Nepeta L., Sp. Pl.: 570 (1753).
    Temp. Eurasia Macaronesia to E. Trop. Africa. 1 Species introduced to Neotropics
  • Obtegomeria Doroszenko & P.D.Cantino, Novon 8: 2 (1998).
    W. South America. 83. 1 Species
  • Ocimum L., Sp. Pl.: 597 (1753).
    Trop. & Subtrop. 10 Species
  • Origanum L. 1 Species introduced to Neotropics, native to Macaronesia, Europe, Medit. to C. China
  • Peltodon Pohl, Pl. Bras. Icon. Descr. 1: 66 (1827).
    S. Trop. America. 5 Species
  • Petitia Jacq., Enum. Syst. Pl.: 1 (1760).
    Caribbean. 81. 3 Species
  • Physostegia Benth. Edwards's Bot. Reg. 15: t. 1289 (1829)
    2 Species, N. America to Mexico
  • Plectranthus L'Hér., Stirp. Nov.: 84, verso (1788).
    Trop. & Subtrop. 4 Species
  • Poliomintha A.Gray, Proc. Amer. Acad. Arts 8: 295 (1873).
    S. U.S.A. to Mexico. 8 Species
  • Prunella L., Sp. Pl.: 600 (1753).
    Temp. & Subtrop. Northern Hemisphere. 1 Species probably naturalised in Neotropics
  • Pseudocarpidium Millsp., Publ. Field Columbian Mus., Bot. Ser. 2: 181 (1906).
    Caribbean. 81. 9 Species
  • Rhaphiodon Schauer, Flora 27: 345 (1844).
    Brazil. 1 Species
  • Rosmarinus L., Sp. Pl.: 23 (1753). 
    1 Species introduced to Neotropics, native to Mediterranean
  • Salvia L., Sp. Pl.: 23 (1753).
    Cosmopolitan. 605 Species
  • Scutellaria L., Sp. Pl.: 598 (1753).
    Cosmopolitan. 96 Species
  • Stachys L., Sp. Pl.: 580 (1753).
    Cosmopolitan. 72 Species
  • Tectona L.f., Suppl. Pl.: 151 (1781), nom. cons. 
    1 Species introduced to Neotropics, native to Tropical Asia
  • Teucrium L., Sp. Pl.: 562 (1753).
    Cosmopolitan. 10 Species
  • Tinnea Kotschy & Peyr., Pl. Tinn.: 25 (1867). 
    1 Species introduced to Neotropics, native to Trop. & S. Africa
  • Trichostema L., Sp. Pl.: 598 (1753).
    N. America. 8 Species
  • Vitex L., Sp. Pl.: 638 (1753).
    Trop. & Subtrop. 61 Species
  • Warnockia M.W.Turner, Pl. Syst. Evol. 203: 78 (1996).
    C. U.S.A. to NE. Mexico. 1 Species

Useful tips for generic identification

Grouped into seven subfamilies, five of which are native in the Neotropics:

Symphorematoideae: Congea Roxb.(planted):

Viticoideae (transferred from Verbenaceae sensu Briq.):

Ajugoideae (some genera transferred from Verbenaceae sensu Briq.):

Scutellarioideae (In Neotropics):

  • Calyx usually 2-lipped with lips entire e.g. Scutellaria Riv. ex L.
  • Posterior lip of calyx usually folded to form a scutellum.

Lamioideae (wide range of genera e.g. Stachys L. Several genera widely introduced as weeds (Lamium L., Marrubium L., Leonitis Spach, Leonurus L.):

Nepetoideae:

  • Often aromatic.
  • Pollen hexacolpate (other subfamilies usually tricolpate e.g. Salvia L., Hyptis Jacq., Minthostachys (Benth.) Spach, Clinopodium L.).
  • Many genera introduced and cultivated.
  • Prunella L. naturalized in montane areas.

Notable genera and distinguishing features

Salvia:

  • Recognizable by its unusual stamen structure. 
  • Salvia only expresses two stamens, and the thecae on each stamen are separated by an elongate connective. 
  • This staminal structure is associated with a pollination syndrome in which the pollinator pushes against the posterior (usually sterile) anther theca while accessing a nectar reward at the base of the corolla tube. This causes the anterior (fertile) anther theca to deposit pollen on the pollinator via a lever-like mechanism.
  • At least 500 species in Central and South America.
  • The infra-generic classification proposed, especially by Briquet (1897), largely based on staminal structure, is out-dated, though the Neotropical subgenera Calosphace Benth. and Audibertia (Benth.) Epling appear to be monophyletic.

Hyptis:

  • Flowers arranged variously, often in pedunculate or sessile, congested cymes or involucrate capitula in terminal panicles, or in spikes or axillary.
  • Flowers sometimes in lax cymes, rarely fasciculate on long pedicels in the axils of the leaves.
  • About 280 species, mostly tropical and subtropical savannas, sometimes in humid areas, almost entirely New World, from southern U.S.A. to Caribbean and S to Argentina and Peru, a few species extending into Old World.

Status

  • See Neotropical genera

General notes

 

Important literature

Harley*, R.M., Atkins*, S., Budantsev, A.L., Cantino, P.D., Conn, B.J., Grayer*, R., Harley*, M.M., de Kok*, R., Krestovskaja, T., Morales, R., Paton*, A.J., Ryding, O. & Upson, T. (2004). Labiatae. In Kadereit, J.W. (ed.) The families and genera of vascular plants. Vol. VII, Lamiales. Berlin: Springer. 167-282.

How to cite

Bramley, G., Harley, R. & Paton, A. (2009). Neotropical Lamiaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Lamiaceae.htm.