The genus Syncolostemon ( Lamiaceae )

The genus Syncolostemon E. Mey. ex Benth. is revised and its relationship with Hemizygia (Benth.) Briq.f is discussed. A new species, S. comptonii Codd is described and the following new combinations are made: S. parviflorus var. lanceolatus (Guerke) Codd ( = S . lanceolatus Guerke) and S. latidens (N.E. Br.) Codd ( = Orthosiphon latidens N .E . Br.).

In his revision of the genus Hemizygia Briq. in J. Bot. Lond. 73: 343 (1935), Ashby drew attention to the floral differences between this genus and Ortho siphon Benth.but hardly touched on the genus Syncolostemon E. Mey.ex Benth.
The corolla characters in Syncolostemon and Hemizygia are essentially the same and lend no support for their separation as distinct genera: the tube is longer than the calyx, straight or slightly decurved, widening about the middle towards the truncate m outh; the upper corolla lip is usually very small, obscurely 4-lobed, while the lower lip is shallowly concave and longer than the upper lip.The stamens are in two distinct pairs with the upper (posticous) pair attached at or below the middle of the corolla tube, with the filaments free and usually pubescent towards their base; the lower (anticous) pair are attached at the corolla throat with the fila ments united (united only near the base in H. persimilis and somewhat variable in H. pretoriae).
The only character which shows some promise as a basis for separating the two genera is the shape of the calyx.In typical Syncolostemon the calyx is more or less equally 5-toothed, while in Hemizygia the upper calyx tooth is broadly ovate, often decurrent on the calyx tube, and much larger than the lower four which are usually subulate to almost spinescent.There are, however, certain intermediates which are discussed more fully below.
Syncolostemon E. Mey.ex Benth. in E. Mey., Comm. 230 (1837) was erected to accommodate certain plants collected by Drege.F our species were described which fall into two distinct groups: Group 1: S. parviflorus E. Mey.ex Benth.Calyx and corolla sm all: M ature calyx less than 8 mm long, campanulate, often becoming subrotund, setose in the throat; corolla tube 6-10 mm long; inflorescence lax; nutlets with a frill at the base.
To Group 1 the following may be added: S. concinnus N.E.Br., S. argenteus N.E.Br., S. eriocephalus Verdoorn and the presently described S. comptonii Codd.The species S', macrophyllus Guerke, although showing a distant relationship with S. parviflorus, has a broadly ovate upper calyx tooth and is transferred to Hemizygia.
Closely related to G roup 2 are two species described as Orthosiphon macranthus Guerke and O. latidens N.E.Br. in which the upper calyx tooth is distinctly larger than the lower four, but is elliptic to broadly elliptic rather than broadly ovate.These two species are therefore, somewhat intermediate between Syn colostemon and Hemizygia and Ashby transferred the former to Syncolostemon and the latter to Hemizygia.They are both so obviously related to S. rotundifolius that it is logical to place all three in the same genus.
It is a m atter of convenience to maintain both genera and this may be done on the following basis:  , Gen. ed. 2: 651 (1951), lists S. densiflorus as the lectotype species without giving reasons for his choice.It will be noted that S. densiflorus belongs to G roup 2, which tends to grade into Hemizygia.Should this group be merged with Hemizygia, the older name Syncolostemon would then take prece dence, with the result that some 30 names in Hemizygia would have to be transferred to Syncolostemon; on the other hand, G roup 1 might be considered sufficiently different to be maintained as a distinct genus and would need a new name.It is therefore considered that a better choice of lectotype would be S. parviflorus E. Mey.ex Benth., belonging to G roup 1 M ey. ex Benth. in E. Mey., Comm. 230 (1837);Benth. in DC., Prodr. 12: 53 (1848);Benth. & Hook, f., Gen. PI. 2 ,2 : 1174(1876);Briq. in Pflanzenfam. 4 ,3 a : 364 (1897);N.E. Br. in FI. Cap. 5,1: 261 (1910);Phillips, Gen. ed. 2: 651 (1951);Ross, FI. N atal 306 (1972).
Soft shrubs or stems herbaceous, arising annually from a perennial woody rootstock.Leaves opposite, subsessile or shortly petiolate, variously pubescent and gland-dotted, entire or toothed.Inflorescence terminal, sometimes on short lateral shoots, paniculate or simple, lax or dense; verticillasters 2-6-flowered Calyx variously pubescent and often setose in the throat, subequally 5-toothed or the upper tooth larger than the lower 4, elliptic to broadly elliptic, not decurrent on the tube; lower 4 teeth deltoid to subulate.Corolla bilabiate; tube longer than the calyx, widening from about the middle to a truncate m outh; upper lip small, obscurely 4-lobed; lower lip concave, horizontal, longer than the upper lip.Stamens 4, exserted, didynam ous; upper pair affixed about the middle or towards the base of the corolla tube, filaments free, pubescent below; lower pair attached at the corolla throat, filaments connate for practically their entire length, glabrous.Style exserted, minutely bilobed at the apex.Nutlets oblong in outline, sometimes slightly frilled at the base.
Endemic in south-east Africa, extending from the Transkei to the Transvaal; 9 species recognized.Briquet, I.e., divided the species into two sections, corresponding to Groups 1 and 2 above, which he designated as Sect.Micranthi and Sect.M acranthi, respectively.
Found in mountain grassland, usually among rocks, in eastern and south-eastern Transvaal, southern Swaziland and north-eastern Orange Free State; main flowering season is February-M arch.With its slender stems and small white flowers, S. concinnus is an inconspicuous plant, closely related to the next species S. parviflorus.It differs in having stellate (branched) hairs, often minute, on the leaves and sometimes on other parts as well.The two specimens from Swaziland, Compton 28664 and 28757, differ in having very dense stellate pubescence on the leaves, rhachis and calyx.This is the most northerly member of the genus, extending to the Lydenburg District.
Distribution and ecology as for the species.Grades into var.parviflorus and so varietal status appears appropriate.There is also an indication of introgression with S. argenteus, especially where the two tend to meet in Pietermaritzburg district.S. argenteus is a more robust species with a semi coastal distribution and with markedly sericeous leaves.
Although closely related to S. parviflorus E. Mey.ex Benth., the specimen appears to be sufficiently distinct to be separated as a species.It is taller (160 cm), the inflorescence is compact with verticillasters 2-3 mm apart, and the bracts are chartaceous, broadly ovate, as broad as long, with a fringe of woolly hairs.In S. parviflorus the stems are 40-100 cm tall, the inflorescence is lax with verticillasters up to 2 cm apart, and the bracts are ovate-lanceolate, without a fringe of woolly hairs.Bull. 1937Bull. : 447 (1937)).Type: Transvaal, Pilgrim's Rest, Morisse 51.
Found in shallow sandy soil am ong quartzite rocks along the Drakensberg escarpment from Pilgrim's Rest to near The Downs, at altitudes o f 1 400 to 2 000 m. Collected in flower from July to February.A very distinctive species because o f its shrubby habit, small grey leaves, dense small inflorescences nearly obscured by woolly hairs and small cream to yellowish-brown flowers.
Distributed from Keiskamma Hoek in the eastern Cape Province to about Nongom a in N atal, in dense grassland often adjoining forest, at altitudes up to 1 000 m.It has been collected in flower between November and July, but the main flowering time is from February to May.The species may be distinguished by its subulate calyx teeth 3-5 mm long, the upper tooth being often shorter than the lower four.S. rotundifolius E. Mey ex Benth.has shorter, more deltoid calyx teeth, and the verticillasters are 2-flowered.
The type of S. ramulosus E. Mey.ex Benth.has teeth somewhat intermediate between S. densiflorus and S. rodundifolius and, as it has 4-6-flowered verticillasters, it is included in the former.N o modern material exactly m atching it has been seen.
With its dense inflorescences of pink to reddish flowers, S. densiflorus makes an attractive garden subject but attem pts to cultivate it have not been successful in the Transvaal. 7.
Found in grassland and scrub on rocky slopes from about Port St. Johns to Port Shepstone, usually not far from the sea at altitudes up to 400 m.Main flowering season between December and May.Related to S. densiflorus Benth., but the calyx teeth are shorter and more deltoid, the verticillasters are 2-flowered, and the stems, leaves and calyx have a short, soft appressed tomentum, as distinct from the scabrid, hispidulous pubescence of S. densiflorus.
There is also a close resemblance with S. macranthus (Guerke) Ashby of the N atal Drakensberg area, but the latter has usually 4-6-flowered verticillasters, while the upper calyx tooth is obovate-elliptic and distinctly larger than the other four.The leaves of S. macranthus also tend to be larger and more acute at the apex, with a short scabrid pubescence.
Recorded from a restricted area of the Drakensberg between Cathedral Peak and Van Reenens Pass, where it is locally frequent along streams and forest margins at altitudes of 1 600-2 200 m.Although Cooper 1015 (K.) is said to have been collected in the " Orange River Colony" , this requires confirmation as all modern gatherings are from the Natal side of the border.Flowering mainly from January to May.Soft shrub 1-1,5 m tall, branching; branches hispidulous.Leaves petiolate; petiole 3-10 mm long, tomentulose; blade ovate to broadly ovate, 3-5 cm long, 2 -3 ,5 cm broad, drying dark brown, tomentulose on both surfaces, especially on the nerves; apex obtuse to acute, base obtuse to truncate; margin crenate-dentate.Inflorescence a fairly dense terminal panicle, 10-20 cm long; rhachis hispid; bracts caducous, broadly ovate, acute, 5 mm long, sparingly pubescent; verticillasters 6-flowered, 4-8 mm apart; pedicels 1 mm long, hispid.Calyx 10-11 mm long, cylindrical, glandular-hispid, purple, not villous in the m outh; upper tooth the largest, broadly obovate, 3-3,5 mm long, rounded at the apex, not decurrent; lower 4 teeth lanceolate-deltoid, flat, tapering gradually, 2,5 mm long.Corolla mauve-pink to deep pink, 22-25 mm long; tube 20-22 mm long, widening beyond the middle to 5-6 mm wide at the mouth, finely pubescent, particularly on the lobes; upper lip short; lower lip concave 3-5 mm long, often deflexed at maturity.Stamens exserted by 10-12 mm; upper pair inserted below the middle of the corolla tube, puberulous near the base.
Known only from a restricted area near Kranskop in central Natal, growing in and near the forest margin.Flowering is mainly from March to May.Closely related to S. macranthus but differs in the stronger pubescence, the broader lower calyx teeth and the somewhat shorter corolla.The leaves tend to dry a dark brownish colour, which is not the case with S. macranthus.These two species are somewhat intermediate between Syncolostemon and Hemizygia but the former genus is preferred because the upper calyx tooth, although broad, is not decurrent on the tube and the lower calyx teeth are not markedly subulate or spine-like.They are also more closely allied to S. rotundifolius and S. densiflorus than they are to any Hemizygia species.
The four species are very showy and should make good horticultural subjects.Unfortunately initial attempts to cultivate them have not been successful but they are worth persisting with until the difficulties are overcome.
Found from the Transkei to Barberton District in the Transvaal, in dense grassland, often among rocks, from near sea level in Natal in 1 800 m altitude in the Transvaal; flowering is mainly from January to March.Two varieties are recognized; for key to varieties, see key to species.(a) var.parviflorus.

Orthosiphon latidens N .E. Br. in FI. Cap. 5,1: 242 (1910). Type: Natal, Um voti District, Gerrard 1233 (K , holo.). H em izygia latidens (N .E. Br.) Ashby in J. Bot. Lond. 73: 348 (1935); Ross, FI. Natal 306 (1972).
Differs from S. rotundifolius in the calyx having the upper tooth larger than the lower four, the larger, more acute leaves and the fine scabrid pubes cence of stems and leaves.S. latidens (N.E.Br.)Codd differs from it in the leaves having a fine appressed tomentum and the calyx hispid with the lower four calyx teeth deltoidlanceolate, not acuminate as in S. macranthus.The two are closely related but the distribution is different, S. latidens occurring in a restricted area near Kranskop.Briquet in Bull.Herb.Boiss.ser. 2 ,3 : 993 (1903) considered that H. cooperi Briq.occupied an isolated position in Hemizygia and made it the type of a new section, Sect.Cooperozygia Briq.H. cooperi is conspecific with S. macranthus, which is so obviously allied to S. rotundifolius that Ashby is considered justified in placing it in Syncolostemon.