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

[FSOM]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Herbs or shrubs,with unbranched hairs only
Morphology Reproductive morphology Inflorescences
Inflorescences thyrse-like, lax or dense; bracts ± leaf-like; cymes 1–many-flowered, usually dense, often forming globose verticillasters, with bracteoles
Morphology Reproductive morphology Flowers Calyx
Calyx 5–10-lobed, mostly distinctly zygomorphic, distally c.10-ribbed, sometimes with a ring of hairs inside the tube; lobes unequal or sometimes equal
Morphology Reproductive morphology Flowers Corolla
Corolla 2-lipped, white to cream; upper lip hooded, emarginate, ± falcate or sometimes almost straight, densely hairy and bearded along the margin with white or cream hairs; lower lip straight or deflexed, 3-lobed with the midlobe usually larger and often emarginate
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens included in the upper lip of the corolla
Morphology Reproductive morphology Flowers Gynoecium Style
Style-branches subequal, or lower usually distinctly longer
Morphology Reproductive morphology Fruits
Nutlets obovoid, obpyramidal, oblong or ellipsoid, often sharply trigonous, truncate or rounded at the apex, usually with sessile glands at the apex, or sometimes glandular all over.
Distribution
Genus of over 110 species in tropical Africa and tropical Asia, a few have become introduced to other parts of the tropics.

[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.

Morphology General Habit
Annual or perennial herbs or subshrubs with simple hairs
Morphology Leaves
Leaves usually toothed, petiolate or at least narrowed at base
Morphology Reproductive morphology Inflorescences
Inflorescence thyrsoid or rarely racemoid
Morphology Reproductive morphology Flowers Calyx
Calyx zygomorphic, 2-lipped, or sometimes actinomorphic, 5-10(-12)-lobed, lobes variously unequal or rarely equal, mostly spinose
Morphology Reproductive morphology Flowers 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
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens not or only shortly exserted from corolla, thecae confluent or weakly distinct
Morphology Reproductive morphology Flowers Gynoecium Stigma
Stigma-lobes unequal to sometimes equal
Morphology Reproductive morphology 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

Morphology General Habit
Annual or perennial herbs, subshrubs or small shrubs
Morphology Stem
Stems erect, ascending or procumbent, usually pubescent with upward or downward-pointing to spreading hairs
Morphology Leaves
Leaves simple, opposite, sessile to distinctly petiolate
Morphology Reproductive morphology 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
Morphology Reproductive morphology Flowers Calyx
Calyx tubular, throat symmetric to slightly oblique to asymmetric (lipped); lobes 5–10
Morphology Reproductive morphology Flowers 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
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 4; filaments with eglandular hairs about halfway up; thecae divaricate, confluent or weakly distinct
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary 4-lobed, style gynobasic, unequally lobed
Morphology Reproductive morphology 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.

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 Somalia

  • Flora Somalia, (2000) Author: by O. Ryding [updated by M. Thulin 2008]
  • Sebald in Stuttgarter Beitr. Naturk. Ser. A 308: 1–42 (1978)
  • Sebald in Stuttgarter Beitr. Naturk. Ser. A 341: 1–200 (1980).

Flora of Tropical East Africa

  • Kubitzki, Fam.-Gen. Vasc. Pl. 7: 227 (2004)
  • Prodr. Fl. Nov. Holl.: 504 (1810)
  • Stuttgarter Beitr. Naturk., ser. A, 308: 1–42 (1978)
  • Stuttgarter Beitr. Naturk., ser. A, 308: 1–42 (1978) & 341: 1–200 (1980)
  • Stuttgarter Beitr. Naturk., ser. A, 341: 1–200 (1980)

Lamiaceae Key Genus Fact Sheets

  • Blandinia Raf., Fl. Tellur. 3: 88 (1837).
  • Elbunis Raf., Fl. Tellur. 3: 88 (1837).
  • Eneodon Raf., Fl. Tellur. 3: 88 (1837).
  • 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
  • Hemistemma Rchb., Consp. Regn. Veg.: 116 (1828).
  • Hemistoma Ehrenb. ex Benth. in N.Wallich, Pl. Asiat. Rar. 1: 60 (1830).
  • Heptrilis Raf., Fl. Tellur. 3: 89 (1837).
  • Hetrepta Raf., Fl. Tellur. 3: 88 (1837).
  • Isodeca Raf., Fl. Tellur. 3: 88 (1837).
  • Lasiocorys Benth., Labiat. Gen. Spec.: 600 (1834).
  • Leucas Burm. ex R. Br., Prodr. Fl. Nov. Holl.: 504 (1810)
  • Leucasia Raf., Fl. Tellur. 3: 88 (1837).
  • Physoleucas Jaub. & Spach, Ill. Pl. Orient. 5: 48 (1855).
  • Sebald, Stuttgarter Beitr. Naturk. A. 308: 1-42 (1978)
  • Sebald, Stuttgarter Beitr. Naturk. A. 341: 1-200 (1980)
  • Singh, Monograph on Indian Leucas R. Br. (Dronapushpi) Lamiaceae (2001).

Flora of Somalia
Flora of Somalia
http://creativecommons.org/licenses/by-nc-sa/3.0

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

Herbarium Catalogue Specimens

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. 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 2021. 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/