Orthosiphon Benth.

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

Type

Type species: Ocimum triste Roth [= Orthosiphon thymiflorus (Roth) Sleesen (Ocimum thymiflorum Roth ) ].

Morphology General Habit

Erect herbs or undershrubs

Morphology Stem

Stems sometimes with a woody rootstock, quadrangular or round- quadrangular, usually branched

Morphology Leaves

Leaves with lower pairs petiolate, upper pairs sometimes sessile or subsessile, opposite, sometimes leaves forming a rosette near stem base, membranous to chartaceous, serrate, crenate or entire

Morphology Reproductive morphology Inflorescences

Inflorescence terminal, simple, rarely branched; verticils clearly interrupted; cymes sessile, unbranched, 1 - 3-flowered, often 3- flowered; bracts caducous or persistent, often forming an apical coma; pedicels bent downward in fruit

Morphology Reproductive morphology Flowers Calyx

Calyx campanulate in flower, tubular- campanulate in fruit, bilabiate, reflexed against the inflorescence axis in fruit; posterior lip membranous, broadest, margins reflexed, strongly decurrent on tube; anterior lip 4-toothed with teeth acuminate- subulate, two median teeth longer than lateral, subequal or longer than posterior; tube sometimes constricted above ovary, with 10 longitudinal veins, without anterior spur at base; throat mostly glabrous, rarely pubescent

Morphology Reproductive morphology Flowers Corolla

Corolla long exserted from calyx tube; posterior lip 3 - 4-lobed, equal or the median lobe larger; anterior lip entire, concave, equal to posterior or longer; lobes pubescent at back; tube long exserted, straight or incurved, pubescent

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, didynamous, declinate, included or long exserted, inappendiculate, glabrous; posterior pair attached at throat slightly below anterior; anterior pair attached at the base of anterior corolla lip, longer than posterior; filaments free; anthers reniform, synthecous, often confluent

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary glabrous

Morphology Reproductive morphology Flowers Gynoecium Style

Style declinate, capitate or clavate at apex, usually slightly cleft, often with minute glands around style base

Morphology Reproductive morphology Flowers Disc

Disc 4-lobed with anterior side well developed

Morphology Reproductive morphology Fruits

Nutlets ovoid, ellipsoid, oblong or globose, smooth, minutely tuberculate or minutely reticulate, sometimes producing mucilage when wet.

Note

Index Nominum Genericorum (Farr et al. 1979), Flora of Southern Africa (Codd 1985), NCU-3 (Greuter et al. 1993) regarded Orthosiphon as 'type not designated'. Flore de Madagascar et des Comores (Hedge et al. 1998) cited Orthosiphon rubicundus (D. Don) Benth as the type species and Conspectus Lamiacearum Florae Vietnami (Phuong 1982), Flora of Vietnam 2 (Phuong 2000) cited it as the lectotype species. The original publication of the genus mentions only one species, 'Ocimum triste Roth' which Bentham definitely indicated belonged to the genus, and so this must be the type species for the genus. Ocimum triste Roth has never been combined in Orthosiphon, but it is a synonym of Orthosiphon thymiflorus (Roth) Sleesen (Ocimum thymiflorum Roth)

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, suffrutices or shrubs

Morphology Stem

Stems erect, often woody at base

Morphology Leaves

Leaves opposite

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, arranged in 2–6-flowered verticils disposed in a lax inflorescence; bracts small, sometimes forming an inconspicuous apical coma

Morphology Reproductive morphology Flowers Calyx

Calyx persistent, horizontal or downward-pointing, shortly tubular, bilabiate; posterior lip large, ovate, entire, apex sometimes cuspidate, shortly decurrent on tube; anterior lip 4-lobed, lateral lobes deltate, cuspidate, median lobes lanceolate, long acuminate; fruiting calyx with throat open, glabrous, posterior lip accrescent, lateral lobes of anterior lip often with the posterior margin extended towards or under the posterior lip and with a small lanceolate or subulate tooth, median lobes acicular or subulate, curving upwards, longer than lateral lobes

Morphology Reproductive morphology Flowers Corolla

Corolla bilabiate, white, pink or bluish; tube funnel-shaped or straight and ± parallel-sided, dilating slightly towards throat, exceeding the calyx or subequal to it; posterior lip perpendicular to tube, 4-lobed, with the median narrower than and exceeding the lateral; anterior lip entire, horizontal and cucullate, enclosing the stamens or deflexed

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4, declinate, shortly exserted or enclosed within the anterior lip; posterior pair inappendiculate, basally ciliate or glabrous, adnate to the corolla above the midpoint of the tube; anterior pair glabrous, adnating nearer throat, anthers dorsifixed, synthecous

Morphology Reproductive morphology Flowers Disc

Disk 4-lobed, with anterior lobe larger

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary glabrous, deeply 4-lobed; style gynobasic, capitate, branches rounded, equal, adpressed

Morphology Reproductive morphology Fruits

Nutlets brown, ovoid with a small basal scar, minutely tuberculed, producing a small amount of mucilage when wet; embryo straight, exalbuminous.

Note

Ashby, loc. cit. (1938) divided the genus into three sections, sect. Serrati M.Ashby, Orthosiphon ( Euorthosiphon M.Ashby) and Pallidi M.Ashby. Codd, loc. cit. (1964), expanded sect. Serrati to include Nautochilus Bremek. and treated it as a subgenus, Orthosiphon subgen. Nautochilus (Bremek.) Codd. Subgen. Nautochilus in a more restricted sense, i.e. those species with stamens hairy at the base, exserted and attaching to the corolla in its basal half, and also with a bifid style, has now been transferred to Ocimum, see generic notes under Ocimum. Ashby described sect. Pallidi for species with a supposedly funnel-shaped corolla and the anterior corolla lip being longer than the posterior. O. hanningtonii, which has a funnelshaped corolla and equal corolla lips, is intermediate between sect. Pallidi and sect. Orthosiphon. The difference between a funnel-shaped tube and the parallel-sided tube that dilates at the throat, found in the remainder of Orthosiphon¸ is very slight. The corolla of O. pallidus seems to be very similar in shape to other members of Orthosiphon, but the tube is shorter making it appear funnel-shaped. Only O. hanningtonii has a properly funnel-shaped corolla tube, in that the extended sides of the exserted part of the tube are not parallel. Therefore, in Orthosiphon there seems to be a continuous variation in the tube shape between parallel-sided and dilating at the throat on one hand, and funnel-shaped on the other. Due to this unconvincing character difference and the intermediate position of O. hanningtonii, sect. Pallidi is not recognised here.

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

Morphology General Habit

Subshrubs or herbs

Morphology Reproductive morphology Inflorescences

Inflorescences thyrse-like, lax or rather lax, with recurved flowers; bracts distinctly smaller than the leaves; cymes (1–)3-flowered, without peduncle or almost so; bracteoles absent

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed; upper lobe large, concave, decurrent along the distal third of the tube; lateral lobes broad at the base, subulate at the apex; lower lobes subulate and longer than the lateral lobes (in Somali species)

Morphology Reproductive morphology Flowers Corolla

Corolla strongly 2-lipped; tube straight, narrowly to broadly cylindrical; upper lip 3–4-lobed, almost flat; lower lip shallowly boat-shaped

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens inserted in the distal part of the corolla-tube, directed to or included in the lower lip of the corolla; anthers 1-celled

Morphology Reproductive morphology Flowers Gynoecium Style

Style club-shaped; branches minute

Morphology Reproductive morphology Fruits

Nutlets ovoid to subglobose, minutely bullate, glabrous.

Distribution

Genus with over 40 species, many in tropical and southern Africa, some in tropical and subtropical Asia.