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This genus is accepted, and its native range is Tropical & S. Africa to Australia.
Platostoma calcaratum

[KBu]

Suddee, S., A. J. Paton, & Parnell, J. (2005). Taxonomic Revision of Tribe Ocimeae Dumort. (Lamiaceae) in Continental South East Asia III. Ociminae. Kew Bulletin, 60(1), 3-75. Retrieved from http://www.jstor.org/stable/4110885

Morphology General Habit
Erect or ascending annual or perennial herbs or undershrubs, sometimes producing stolons
Morphology Leaves
Leaves sessile or petiolate, clearly opposite or pseudo-verticillate in appearance due to the presence of axillary young leaves, membranous or chartaceous, entire, serrate or crenate
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 4, didynamous, clearly or slightly declinate; posterior pair included or exserted, attached around the midpoint or at the base of corolla tube, pubescent or villous, appendiculate or not; anterior pair longer, exserted, rarely included, attached on throat around the base of the anterior corolla lobe, glabrous or pubescent, inappendiculate; filament free, dilated toward base; anther reniform, synthecous, often confluent
Morphology Reproductive morphology Flowers Calyx
Calyx campanulate in flower, tubular or campanulate in fruit, declinate or suberect, bilabiate; posterior lip 1- lobed or 3-lobed with lateral lobes conspicuous or obscure, median lobe broadest, decurrent on tube or not, sinus between median and lateral lobes usually with a black patch; anterior lip 1 - 4-lobed, straight or curved upwards and sometimes closing throat; tube constricted at throat, with 8 - 10 longitudinal veins, sometimes pitted with secondary transverse veins, with or without an anterior spur at base; throat glabrous
Morphology Reproductive morphology Flowers Corolla
Corolla short or long exserted from calyx tube; posterior lip 3 - 4-lobed, equal or subequal; anterior lip entire, ciliate or fimbriate, slightly to strongly concave, equal or slightly longer than posterior; tube short or long, gibbous or with prominent spur on posterior base, glabrous or pubescent
Morphology Reproductive morphology Flowers Disc
Disc lobed with the anterior side usually well developed, exceeding ovary or not
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary glabrous
Morphology Reproductive morphology Flowers Gynoecium Style
Style declinate, bifid with equal or unequal branches
Morphology Reproductive morphology Fruits
Nutlets ovoid, ellipsoid or oblong, smooth, minutely tuberculate or reticulate, sometimes papillose or with hairs at apex, sometimes producing mucilage when wet.
Morphology Reproductive morphology Inflorescences
Inflorescence terminal or axillary, simple or branched, usually subtended by 2 or more spreading, basally pale or coloured, leaf-like bracts, often persistent; verticils varying from clearly interrupted to adjacent verticils arranged close together forming a lax or dense capitulum or spike-like inflorescence; cymes sessile or subsessile, branched or not, 2 - many flowers; upper bracts small, sometimes forming an apical coma, caducous or persistent; pedicels rounded or flattened, sometimes with narrow wing on each side, sometimes curved upwards into one side and the infructescence becomes secund
Morphology Stem
Stems round, quadrangular or round-quadrangular, branched or not
Note
For generic discussion and subgeneric classification within the Platostoma group see Paton (1997). In some species, the habit and the number of lobes on the posterior calyx lip varies, and the corolla spur is sometimes less conspicuous. These variable features can make identification difficult.
Type
Type species: P. africanum P. Beauv. Mesona Blume

[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
Herbs, sometimes geoxylic, not or faintly aromatic
Morphology Leaves
Leaves simple
Morphology Reproductive morphology Inflorescences
Inflorescence thyrsoid, lax or more rarely condensed with cymes sessile, usually >3-flowered, more rarely 3-flowered
Morphology Reproductive morphology Inflorescences Bracts
Bracts persistent, often basally coloured
Morphology Reproductive morphology Flowers Calyx
Calyx tubular, campanulate or urceolate, curving upwards or straight, 2-lipped, 2- to 8-lobed (1-3/1-5), lobes unequal, posterior lip entire with rounded or acute apex or 3-lobed, with posterior lobe decurrent or not, anterior lip entire and rounded, emar
Morphology Reproductive morphology Flowers Corolla
Corolla 2-lipped, 5- or 4-lobed (3-4/1), white, pink or blue, posterior lip ascending, 3-4-lobed, anterior lip horizontal, entire, slightly concave, corolla-tube straight, dorsally gibbous at midpoint or spurred near base, dilating towards throat
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 4, declinate or spreading, exserted, posterior pair attached around midpoint of corolla, basally pubescent and swollen, sometimes appendiculate, anterior pair attached at corolla throat or near midpoint
Morphology Reproductive morphology Flowers Gynoecium Stigma
Stigma-lobes equal, linear
Morphology Reproductive morphology Flowers Disc
Disc 4-lobed with anterior lobe larger
Morphology Reproductive morphology Fruits
Nutlets ovoid, minutely striate, usually weakly mucilaginous when wet.
Note
2n = 14, 18, 28, 30, 42, 48.  Forty-five species
Distribution
In Tropical Africa and Asia, also in Australia (Queensland)
Ecology
Grassland, open woodland often in wet areas.

[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. Flora of Tropical East Africa. 2009

Morphology General Habit
Annual or perennial herbs, with stems arising from a taproot, slender rhizome or small woody rootstock, not or scarcely aromatic
Morphology Stem
Stems prostrate, ascending or erect
Morphology Leaves
Leaves opposite, petiolate; upper leaves sometimes basally pale or coloured
Morphology Reproductive morphology Flowers
Flowers hermaphrodite, arranged in mostly more than 3-flowered verticils in a lax to dense inflorescence; bracts usually coloured
Morphology Reproductive morphology Flowers Calyx
Calyx bilabiate, rounded in cross-section; upper lip with 1 or 3 lobes with the posterior lobe decurrent or not; anterior lip with 1–5 lobes, variously arranged; fruiting calyx with the throat open to closed to varying degrees, see note below
Morphology Reproductive morphology Flowers Corolla
Corolla white, pink or bluish to purple, bilabiate, short; tube dorsally gibbous, curved slightly downwards, dilating at throat, pubescent to densely villose within; posterior lip erect, 3–4-lobed, median lobes slightly smaller; anterior lip ± linear, slightly cucullate, horizontal, becoming deflexed
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 4, declinate or spreading, shortly exserted; filaments pubescent, posterior basally swollen, attaching to corolla below midpoint of tube, anterior attaching above midpoint of the tube; anthers orbicular, dorsifixed, synthecous
Morphology Reproductive morphology Flowers Disc
Disk 4-lobed with anterior lobe slightly larger
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary glabrous or pubescent at apex, deeply 4-lobed; style gynobasic, bifid
Morphology Reproductive morphology Fruits
Nutlets black, obovoid, with minute longitudinal ridges and a small white basal scar, sometimes pubescent at apex, not producing mucilage when wet
Note
The genus has been broadened by Paton, loc. cit. (1997) to include Acrocephalus sensu stricto (most species in Africa formerly placed in Acrocephalus are now referred to Haumaniastrum), Geniosporum, Limniboza and Octomeron. The East African species are represented in each of the three subgenera and several subdivisions:

Native to:

Angola, Assam, Bangladesh, Benin, Borneo, Burkina, Burundi, Cambodia, Cameroon, Central African Repu, Chad, China South-Central, China Southeast, Congo, East Himalaya, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Gulf of Guinea Is., Hainan, India, Ivory Coast, Jawa, Kenya, Laccadive Is., Laos, Lesser Sunda Is., Liberia, Madagascar, Malawi, Malaya, Mali, Maluku, Mozambique, Myanmar, Nepal, New Guinea, Nigeria, Northern Provinces, Philippines, Queensland, Rwanda, Senegal, Sierra Leone, Sri Lanka, Sudan, Sulawesi, Sumatera, Swaziland, Taiwan, Tanzania, Thailand, Togo, Uganda, Vietnam, West Himalaya, Zambia, Zaïre, Zimbabwe

Platostoma P.Beauv. appears in other Kew resources:

First published in Fl. Oware 2: 61 (1818)

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: 349, as Platystoma.
  • Fl. Oware 2: 61 (1818)

Flora of Tropical East Africa

  • B.J.B.B. 17: 15 (1943)
  • Fl. Owar. 2: 61, t. 95 (1818)
  • K.B. 52: 257–292 (1997)
  • Kubitzki, Fam. Gen. Vasc. Pl. 7: 263 (2004)

Lamiaceae Key Genus Fact Sheets

  • Acrocephalus Benth., Edwards's Bot. Reg. 15: t. 1282, 13 (1829)., pro parte quoad African and Madagascan species (1830).
  • Ceratanthus F.Muell. ex G.Taylor, J. Bot. 74: 3 (1936).
  • Geniosporum Wall. ex Benth., Edwards's Bot. Reg. 15: t. 1300 (1830).
  • 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
  • Hemsleia Kudô, Mem. Fac. Sci. Taihoku Imp. Univ. 2: 142 (1929).
  • Limniboza R.E.Fr., Wiss. Erg. Schwed. Rhod.-Kongo Exped. 1: 277 (1916).
  • Mesona Blume, Bijdr.: 838 (1826).
  • Nosema Prain, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 73: 20 (1904).
  • Octomeron Robyns, Bull. Jard. Bot. État 17: 28 (1943).
  • Paton, Kew Bull. 52: 257-292 (1997), rev.
  • Platostoma P. Beauv., Fl. Oware 2: 61, t. 95 (1818)

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

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 Bulletin
Kew Bulletin
http://creativecommons.org/licenses/by-nc-sa/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