1. Family: Lamiaceae Martinov
    1. Leucas R.Br.

      1. This genus is accepted, and its native range is Africa to NE. Australia.

    [LKGF]

    Harley, R.M. et al. (2004). Labiatae, in The Families and Genera of Vascular Plants (K. Kubitzki, ed. in chief) VI: 167-275. Springer-Verlag, Berlin, Heidelberg, New York.

    Habit
    Annual or perennial herbs or subshrubs with simple hairs
    Leaves
    Leaves usually toothed, petiolate or at least narrowed at base
    Inflorescences
    Inflorescence thyrsoid or rarely racemoid
    Calyx
    Calyx zygomorphic, 2-lipped, or sometimes actinomorphic, 5-10(-12)-lobed, lobes variously unequal or rarely equal, mostly spinose
    Corolla
    Corolla strongly 2-lipped, 4-lobed (1/3), white or rarely slightly reddish, posterior lip long or moderately long, hooded, bearded and densely pubescent outside with whitish hairs
    Stamens
    Stamens not or only shortly exserted from corolla, thecae confluent or weakly distinct
    Stigma
    Stigma-lobes unequal to sometimes equal
    Fruits
    Nutlets with apex truncate or rounded, with or without glands, otherwise glabrous or rarely shortly eglandular hairy.
    Note
    2n = (20), 22, (24), (26), 28 (30).  About 100 species.
    Ecology
    Mostly dry or disturbed ground
    Distribution
    Tropical to southern Africa, Arabian Peninsula, Iran to Southern China, Taiwan, Japan and Southeastern Asia, some species, especially L. martinicensis (Jacq.) R. Br., introduced as weeds elsewhere.
    [FTEA]

    Lamiaceae (Labiatae), A.J. Paton, G. Bramley, O. Ryding, R.M. Polhill, Y.B. Harvey, M. Iwarsson, F. Willis, P.B. Phillipson, K. Balkwill, C.W. Lukhoba, D.F. Otieno, & R.M. Harley. Leucas, G. Bramley. Flora of Tropical East Africa. 2009

    Habit
    Annual or perennial herbs, subshrubs or small shrubs
    Stem
    Stems erect, ascending or procumbent, usually pubescent with upward or downward-pointing to spreading hairs
    Leaves
    Leaves simple, opposite, sessile to distinctly petiolate
    Inflorescences
    Inflorescence with few to many verticils, congested or laxly spaced; verticils few–many-flowered, usually congested; bracts subtending verticils as leaves, often becoming reduced in size towards inflorescence axis, usually caducous in fruit; bracteoles minute to conspicuous
    Calyx
    Calyx tubular, throat symmetric to slightly oblique to asymmetric (lipped); lobes 5–10
    Corolla
    Corolla white, posterior lip curved inwards at apex, forming a hood over the style and stamens, densely pubescent on the outer surface, the hairs more plentiful, especially erect and downward-pointing along the margin of the hood, these also present on the inner surface of the lip margin; anterior lip divided into three lobes, the centre lobe longer and with a slight division at the apex
    Stamens
    Stamens 4; filaments with eglandular hairs about halfway up; thecae divaricate, confluent or weakly distinct
    Ovary
    Ovary 4-lobed, style gynobasic, unequally lobed
    Fruits
    Nutlets oblong-trigonous to obovoid with a small basal scar
    Note
    The first dichotomy in the key should be used with caution – in general the differences in bracteole length between species following the first lead and those following the second are readily apparent, but occasionally species with bracteoles typically 0.5–3 mm long have some up to 5(–6) mm long (hence the slight overlap in measurements); in this case whether the calyx is accrescent or not must be taken into account, and in addition bracteole shape (lead one species always have linear or subulate bracteoles, and in those following lead two tend to be linearlanceolate to ovate). This account is based on Sebald (1980), a revision of the Leucas of the African continent, the Arabian peninsula and Socotra. Sebald divided the genus into 13 sections: these sections are not listed here, although the species order roughly follows that of Sebald, with the addition of three new species, one new variety and change of status of two others.

    Images

    Distribution

    Native to:

    Afghanistan, Andaman Is., Angola, Assam, Bangladesh, Benin, Borneo, Botswana, Burkina, Burundi, Cambodia, Cameroon, Cape Provinces, Cape Verde, Central African Repu, Chad, China South-Central, China Southeast, Christmas I., Comoros, Congo, Djibouti, East Himalaya, Egypt, Eritrea, Ethiopia, Free State, Gambia, Ghana, Guinea, Guinea-Bissau, Gulf of Guinea Is., Gulf States, Hainan, India, Iran, Ivory Coast, Japan, Jawa, Kenya, KwaZulu-Natal, Laos, Lesser Sunda Is., Liberia, Madagascar, Malawi, Malaya, Maldives, Mali, Maluku, Mauritania, Mauritius, Mozambique, Myanmar, Namibia, Nansei-shoto, Nepal, New Guinea, Nicobar Is., Niger, Nigeria, Northern Provinces, Ogasawara-shoto, Oman, Pakistan, Philippines, Queensland, Rwanda, Saudi Arabia, Senegal, Sierra Leone, Sinai, Socotra, Somalia, South China Sea, Sri Lanka, Sudan, Sulawesi, Sumatera, Swaziland, Taiwan, Tanzania, Thailand, Tibet, Togo, Uganda, Vietnam, West Himalaya, Yemen, Zambia, Zaïre, Zimbabwe

    Introduced into:

    Brazil Northeast, Brazil Southeast, Caroline Is., Cook Is., Costa Rica, Dominican Republic, Fiji, Haiti, Leeward Is., New Caledonia, Niue, Samoa, Seychelles, Society Is., Solomon Is., Tonga, Trinidad-Tobago, Tuamotu, Wallis-Futuna Is., Windward Is.

    Leucas R.Br. appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Jan 1, 1976 Maitland, T.D. [480], Cameroon K000025467
    Ash [1112], Ethiopia 35504.000
    Ash [1118], Ethiopia 35534.000
    Ash [1885], Ethiopia 35605.000
    Ash [1565], Ethiopia 35682.000
    Leeuwenberg, A.J.M. [8502], Cameroon K000025459

    First published in Prodr. Fl. Nov. Holland.: 504 (1810)

    Accepted by

    • Govaerts, R. (2003). World Checklist of Selected Plant Families Database in ACCESS: 1-216203. The Board of Trustees of the Royal Botanic Gardens, Kew.

    Literature

    Flora of West Tropical Africa
    • —F.T.A. 5: 472.
    Flora of Tropical East Africa
    • Kubitzki, Fam.-Gen. Vasc. Pl. 7: 227 (2004)
    • Stuttgarter Beitr. Naturk., ser. A, 308: 1–42 (1978) & 341: 1–200 (1980)
    • Stuttgarter Beitr. Naturk., ser. A, 341: 1–200 (1980)
    • Stuttgarter Beitr. Naturk., ser. A, 308: 1–42 (1978)
    • Prodr. Fl. Nov. Holl.: 504 (1810)
    Lamiaceae Key Genus Fact Sheets
    • Harley RM, Atkins S, Budantsev AL, Cantino PD, Conn BJ, Grayer R, Harley MM, de Kok RPJ, Krestovskaja T, Morales R, Paton AJ, Ryding O, and Upson T. 2004. Labiatae, in The Families and Genera of Vascular Plants (K. Kubitzki, ed. in chief) VI: 167-275. Sp
    • Singh, Monograph on Indian Leucas R. Br. (Dronapushpi) Lamiaceae (2001).
    • Sebald, Stuttgarter Beitr. Naturk. A. 341: 1-200 (1980)
    • Sebald, Stuttgarter Beitr. Naturk. A. 308: 1-42 (1978)
    • Physoleucas Jaub. & Spach, Ill. Pl. Orient. 5: 48 (1855).
    • Blandinia Raf., Fl. Tellur. 3: 88 (1837).
    • Elbunis Raf., Fl. Tellur. 3: 88 (1837).
    • Eneodon Raf., Fl. Tellur. 3: 88 (1837).
    • Heptrilis Raf., Fl. Tellur. 3: 89 (1837).
    • Hetrepta Raf., Fl. Tellur. 3: 88 (1837).
    • Isodeca Raf., Fl. Tellur. 3: 88 (1837).
    • Leucasia Raf., Fl. Tellur. 3: 88 (1837).
    • Lasiocorys Benth., Labiat. Gen. Spec.: 600 (1834).
    • Hemistoma Ehrenb. ex Benth. in N.Wallich, Pl. Asiat. Rar. 1: 60 (1830).
    • Hemistemma Rchb., Consp. Regn. Veg.: 116 (1828).
    • Leucas Burm. ex R. Br., Prodr. Fl. Nov. Holl.: 504 (1810)

    Sources

    Flora of Tropical East Africa
    Flora of Tropical East Africa
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Herbarium Catalogue Specimens
    'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Lamiaceae Key Genus Fact Sheets
    Nina Davies, Gemma Bramley and Don Kirkup, Royal Botanic Gardens, Kew
    http://creativecommons.org/licenses/by/3.0

    Plants and People Africa
    Common Names from Plants and People Africa http://www.plantsandpeopleafrica.com/
    © Plants and People Africa http://www.plantsandpeopleafrica.com http://creativecommons.org/licenses/by/3.0/