Five new species of Plectranthus L.Her. (Lamiaceae) from New South Wales and Queensland Paul I. Forster Summary Forster, P I. (2011). Five new species of Plectranthus L.Her. (Lamiaceae) from New South Wales and Queensland. Austrobaileya 8(3): 387-404. Plectranthus caldericola P.I.Forst. from New South Wales and P. bellus P.I.Forst., P. fragrantissimus P.I.Forst., P. insularis P.I.Forst. and P. venustus P.I.Forst. from Queensland are described as new species. All species are illustrated together with notes on their habitat, distribution, affinities and conservation status. Key Words: Lamiaceae, Plectranthus, Plectranthus bellus, Plectranthus caldericola, Plectranthus fragrantissimus, Plectranthus insularis, Plectranthus venustus, Australia flora. New South Wales flora, Queensland flora, taxonomy, new species, conservation status PI. Forster, Queensland Herbarium, Department of Environment & Resource Management, Brisbane Botanic Gardens, Mt Coot-tha Road, Toowong, Queensland 4066, Australia. Email:paul.forster@ derm.qld.gov.au Introduction The genus Plectranthus L.Her. is highly Accumulation of a number of field diverse in Australia with at least 35 described collections, together with a critical species (Blake 1971; Forster 1992,1994,1996, examination of previously described taxa and 1997b, 1999, 2008). As noted previously, herbarium collections, now enable a further speciation in the genus has occurred where five new species to be described, including populations occur in isolated areas such as one long recognized, unnamed species in the mountain peaks or ranges and where suitable group (Forster 2002, 2007a; Bean & Forster habitat exists on areas of exposed rock 2007,2010). Two of these species are currently pavements and outcrops. This suite of habitat known from single populations, whereas the factors has resulted in the ‘islands on islands’ others are more widely distributed. All of effect (Porembski et al. 2000) and is widely the newly described species occur in rocky recognized as being a driving force in genetic areas of pavements and slabs, on a range of diversity and speciation (Carlquist 1974; geological substrates. Grant 1981; Hopper 2000; Seine et al. 2000; Kruckeberg 2002). The swift maturation Materials and methods of Plectranthus individuals from seed (one growing season) with the potential for rapid This work is based on herbarium specimen generation turnover enables speciation within collections in BRI, CANB (including CBG), a given locality if a suitable niche is present and CNS (incorporating QRS) and MEL and once new genetic changes arise in a population. a large collection of live material that was These changes are perhaps most likely to maintained in Brisbane in the 1990s. All occur via genetic drift, rather than selection taxa were examined in habitat. Descriptive for markedly different growth forms. This has terminology is similar to that previously used resulted in subtle differences in morphology (Forster 1994). Conservation assessments are with a ‘non-adaptive radiation’ and a ‘high made using the IUCN (2001) criteria. lineage diversification rate’ (Savolainen & Forest 2005), i.e. there are a lot of similar appearing species in microhabitats that share edaphic and topographic similarities and that are often highly disjunct (Linder 2003). Accepted for publication 16 July 2011 388 Austrobaileya 8(3): 387-404 (2011) Taxonomy x 2.8-3 mm, usually forming a tight coma, non-glandular trichomes dense and shaggy, 1. Plectranthus bellus RI.Forst., species nova divaricate, 6-10-celled up to 1 mm long, affinis P. spectabili S.T.Blake sed indumento glandular trichomes sparse, sessile glands in caulibus et lamina foliorum e trichomatibus occasional; cymes sessile; verticillasters 5 or glandulosis constanti (in illo absentibus) et 6-flowered, up to 7 mm apart; pedicels 2-2.5 eglandulosis divaricatis (adversum antrorsis), x c. 0.5 mm, non-glandular trichomes dense dentibus foliorum 10-19 in quoque latere (in and shaggy, antrorse to divaricate, 6-12- illo 7-12) et lobo superiore calycis oblongo- celled up to 1mm long, glandular trichomes ovato (non lanceolato-ovato) differens. Typus: sparse, sessile glands absent. Flower calyces Queensland. Cook District: Daintree National 3-3.5 mm long, non-glandular trichomes Park, Adeline Creek headwaters, 18 May 1999, dense and shaggy, divaricate, 6-12-celled up P.I.Forster PIF24610 & R.Booth (holo: BRI [2 to 1 mm long, glandular trichomes sparse, sheets]; iso: MEL). sessile glands absent. Corolla 8-10 mm Erect to decumbent herb or subshrub to 100 long, lilac to purple; tube 5-6 mm long, cm high; foliage with very faint ‘lemon’ curved at 90-100° 3-4 mm from the base, scent when crushed, clammy; non-glandular slightly curved upwards, ± glabrous; upper and glandular trichomes uncoloured, sessile lobes suborbicular, reflexed, 2-2.2 x 1.2-1.5 glands 8-celled and yellow. Roots thickened mm, non-glandular trichomes occasional and tuberous to fibrous. Stems square, erect to sparse, divaricate, 4-6-celled up to 0.8 to straggling, succulent, the lower parts up mm long, glandular trichomes and sessile to 12 mm diameter, pale green, upper parts glands absent; lateral lobes oblong, 1.8-2 with persistent indumentum, non-glandular x 1-1.2 mm, glabrous; lower lobe broadly trichomes dense and shaggy, divaricate, ovate, 4.5-5 x 3.8-4 mm, non-glandular 6-16-celled up to 2 mm long, glandular trichomes dense, divaricate, 4-6-celled up trichomes sparse, sessile glands absent. to 1 mm long, glandular trichomes sparse, Leaves discolorous, petiolate; petioles 4-18 x sessile glands absent; filaments filiform, 9-10 2.5-3 mm, channelled on top, non-glandular x c. 0.1 mm, lilac, fused for c. 4 mm from trichomes dense and shaggy, divaricate, 6-16- the base; anthers 0.6-0.7 x 0.4-0.5 mm; style celled up to 2 mm long, glandular trichomes filiform, 10-11 x c. 0.2 mm, lilac, bifid for c. sparse, sessile glands absent; laminae ovate 0.3 mm. Fruit calyces 3-4 mm long; upper to broadly ovate, ± succulent, 10-80 x 10-65 lobe oblong-ovate, 1.8-2 x 0.8-1 mm; lateral mm, crenate with 10-19 teeth up to 2 mm lobes lanceolate-falcate, 2.6-3 x 0.7-0.8 mm; long on each margin, widest above middle, lower lobes lanceolate-falcate, 2.8-3 x 0.3-0.4 secondary teeth usually present; tip acute to mm. Nutlets ± circular in outline, flattened to obtuse; base rounded to truncate; upper surface somewhat convex, 0.7-0.8 mm long, 0.7-0.8 silver-green, velutinous, veins impressed, mm wide, 0.4-0.5 mm thick, glossy brown, non-glandular trichomes dense, divaricate, surface smooth. Fig. 1-3. 4-12-celled up to 1 mm long, glandular Additional specimens examined: Cook District: trichomes absent or scattered to sparse, Hann Tableland, track to Radar tower station. May sessile glands absent; lower surface silver- 2006, Forster PIF31735 & McDonald (BRI); Hann white (due to the indumentum), velutinous, Tableland N.P., Jul 2004, McDonald KRM2982 & Bean (BRI). Cultivated: Tolga (ex plant collected by G. & veins raised, non-glandular trichomes dense N. Sankowsky from base of Hann Tableland), Jul 1995, and shaggy, divaricate, 6-16-celled up to Forster PIF17166 (BRI); Mt Coot-tha Botanic Gardens 2 mm long, glandular trichomes sparse, (ex plant [collector unknown] from Hann Tableland), sessile glands absent. Inflorescence up to 210 Mar 2007, Forster PIF32451 (BRI). mm long, single or with 1-4 side branches, Distribution and habitat: Plectranthus pedunculate for 15-38 mm; axis square in bellus is endemic to north-east Queensland cross-section, non-glandular trichomes dense and has been recorded once from the western and shaggy, divaricate, 4-16-celled up to 2 edge of the Daintree N.R and at two localities mm long, glandular trichomes sparse, sessile on the Hann Tableland. Sterile plants of glands absent; bracts broadly ovate, 3-4.2 what appears to be this species were also Forster, five new species of Plectranthus 389 Fig. 1. Plectranthus bellus. A. flowering stem x0.6. B. abaxial view of leaf xl. C. adaxial view of leaf xl. D. portion of inflorescence with two verticillasters, buds and flowers x2. E. lateral view of flower x4. F. face view of flower x4. All from Forster PIF17166 (BRI). Del. W. Smith. 390 Austrobaileya 8(3): 387-404 (2011) observed at several additional localities in summarized in Table 1; however, the most the foothills of the Hann Tableland in May important differences relate to the overall 2010. Plectranthus bellus is invariably found colour of the plants (due to a combination on rock surfaces and crevices on small (30- of epidermis colour and indumentum cover) 200 m2) areas of granite pavements that form (Fig. 3), together with the form of the flowers. irregular mosaics (‘islands’) within a greater Other species of Plectranthus that also occur area of eucalypt woodlands (Fig. 2 & 3). Only on the Hann Tableland, but were not observed scattered perennial shrubs and small annual to be locally sympatric with P. bellus, include grasses and forbs are found in association. P. apreptus S.T.Blake and P. mirus S.T.Blake. Notes: There are some morphological Plectranthus bellus is a quite spectacular similarities to the much taller growing appearing plant and has considerable potential Plectranthus spectabilis (Forster 1996), that in amenity horticulture and landscaping on has been found close by with at least two account of its attractive foliage, upright form populations within 10 km on upland parts of and the ability to grow in a range of soil types the Hann Tableland. Observed morphological in cultivation. Clones are self sterile, further differences between the two species are adding to its attraction as an amenity plant. Fig. 2. Plectranthus bellus. Habitat at Hann Tableland (population voucher: Forster PIF31735 & McDonald [BRI]) Grasses in background are predominantly exotic species. Photo: P.I. Forster Forster, five new species of Plectranthus 391 Table 1. A comparison of selected morphological character states for Plectranthus bellus and P. spectabilis Character state P. bellus P. spectabilis annual or biennial, herb or life form perennial, herb or subshrub to 1 m tall subshrub to 1.6 m tall indumentum on non-glandular trichomes dense non-glandular trichomes stems and leaf and shaggy, divaricate; glandular sparse to dense, antrorse; laminae trichomes generally present glandular trichomes absent number of teeth on leaf laminae 10-19 7-12 margins up to 320 mm long with 1-11 up to 210 mm long with 1-4 branches branches from near the base inflorescence from near the base; non-glandular or further up the axis; non trichomes divaricate glandular trichomes antrorse calyx indumentum divaricate antrorse lanceolate-ovate, 2.3-4 x upper lobe of calyx oblong-ovate, 1.8-2 x 0.8-1 mm 0.8-1.3 Fig. 3. Plectranthus bellus. Habit of individual plant (population voucher: Forster PIF31735 & McDonald [BRI]). Photo: P I. Forster 392 Austrobaileya 8(3): 387-404 (2011) Conservation status: This species is currently The recommended conservation status known from at least three populations with a for Plectranthus bellus is Vulnerable (criteria known area of occupancy of less than 5 km2. B2,a,b(i,ii,iii,iv,v), D2) based on the IUCN The population in the Daintree N.P. occurs in (2001) categories and criteria. an area that is more or less pristine with little Etymology: The specific epithet is formed evidence of weed infestation. The populations from the Latin word bellus (beautiful) and at the Hann Tableland are besieged by invasive alludes to the pleasing form of this plant. alien weeds that have been spread widely over the tableland by grazing cattle and 2. Plectranthus caldericola P.I.Forst., species uncontrolled wildfires prior to gazettal of the nova a P. graveolenti R.Br. foliis caulibusque area as National Park. These small islands of siccis non viscidis leviter citriodoris (in illo granite pavement are under direct and current humidis viscidis et praeditis odore anti- threat from weeds such as Andropogon septico gravi), foliis dentibus paucioribus gay anus Kunth, Bidens pilosa L., Lantana praeditis (14-18 non 20-42) et apicibus camara L., Melinis minutiflora PBeauv., M. rotundatis (in illo acutis usque ad obtusis), repens (Willd.) Zizka and Praxelis clematidea verticillastris 2-14-floris (adversum 12-15) et R.M.King & H.Rob. that compete for the floribus pedicellis brevioribus praeditis (0.8- scarce resources in these habitats and greatly 1.8 mm non 2-4.5 mm) differt. Typus: New increase fuel loads both on the pavements and South Wales. The Pinnacle, 13 km W of Mt in adjacent vegetation. These Plectranthus Warning, 6 April 1994, P.I. Forster PIF15093 species are unable to survive hot fires with the & G.Leiper (holo: BRI [3 sheets ± spirit]; iso: plants being killed outright or being forced to MEL, NSW). resprout from subterranean rootstocks. Due Subshrub to 50 cm high; foliage with faint to the shallow soils on these pavements, the Temon’ scent when crushed, not clammy; heat and scorch from any fires often tends to non-glandular and glandular trichomes also kill the rootstocks of Plectranthus. The uncoloured to silver, sessile glands 8-celled infrequent occurrence of this species on small and orange. Roots thickened and tuberous. pavements (<20 m2) (Fig. 2) may be regulated Stems square, erect to straggling, fleshy, by fires that occur not necessarily only on the the lower parts up to 15 mm diameter, dark pavement, but in adjacent grassy vegetation. purple, non-glandular trichomes dense and shaggy, divaricate, 6-10-celled up to 3 mm long, glandular trichomes sparse, sessile glands scattered. Leaves discolorous, petiolate; petioles 5-33 x 2-2.5 mm, channelled on top, non-glandular trichomes sparse, divaricate, 6-10-celled up to 3 mm long, glandular trichomes sparse, sessile glands scattered; laminae broadly ovate to almost lobate, fleshy, 10-50 x 10-50 mm, crenate with 7-9 teeth up to 3 mm long on each margin, widest above middle, secondary teeth absent; tip rounded; base truncate, cordate or lobate; upper surface dark-green, veins impressed, non-glandular trichomes sparse, divaricate, 2-8-celled up to 1 mm long, glandular trichomes scattered, sessile glands sparse; lower surface pale-green, veins raised, non-glandular trichomes dense, divaricate, 2-10-celled up to 2 mm long, . glandular trichomes sparse, sessile glands Map 1 Distribution of Plectranthus bellus in north¬ east Queensland. Shaded area on map indicates dense. Inflorescence up to 320 mm long, conservation reserves (National Parks, Forest Reserves comprising 1-5 pedunculate branches from and Conservation Parks). near the base; axis square in cross-section, Forster, five new species of Plectranthus 393 Fig. 4. Plectranthus caldericola. A. flowering stem x0.4. B. abaxial view of leaf xl. C. adaxial view of leaf xl. D. portion of inflorescence with two verticillasters, buds and flower x3. E. lateral view of flower x6. F. face view of flower x6. G. lateral view of fruiting calyx x6. All from Forster PIF15093 & Leiper (BRI). Del. W. Smith. 394 Austrobaileya 8(3): 387-404 (2011) non-glandular trichomes sparse, divaricate, Notes: This species was first brought to my 6-10-celled up to 5 mm long, glandular attention by Graham McDonald in April trichomes dense, sessile glands scattered; 1994. Plectranthus caldericola is distinctive bracts broadly-ovate to obovate, 3-5 x 2.5-4 in the very broad leaves that are sometimes mm, not forming a coma but approaching one, almost lobate, the shaggy indumentum on the non-glandular trichomes dense, divaricate, 6- foliage and the very hairy calyces and very 10-celled up to 3 mm long, glandular trichomes short pedicels. It differs from Plectranthus absent, sessile glands scattered; cymes sessile; graveolens in the non-clammy foliage with verticillasters 2-14-flowered, 5-15 mm a faint Temon’ scent (versus clammy with a apart; pedicels 0.8-1.8 x c. 0.2 mm diameter, strong antiseptic or foetid scent), leaves with non-glandular trichomes dense, divaricate, fewer teeth to the lamina (14-18 versus 20-42) 6-10-celled up to 2 mm long, glandular and rounded tips (versus acute to obtuse), the trichomes absent, sessile glands scattered. 2-14 flowered verticillasters (versus 12-15) Flower calyces 1.8-2 mm long, non-glandular and the flowers with short pedicels (0.8-1.8 trichomes dense and shaggy, divaricate, mm versus 2-4.5 mm). 6-10-celled up to 3 mm long, glandular trichomes absent, sessile glands dense. Corolla The possibility that this species is an 6-9 mm long, dark-purple; tube 3-4 mm long, example of an allotetraploid derived from an ± straight or weakly curved at 160-170° 2-2.5 initial hybridization between Plectranthus mm from base, slightly inflated upwards, graveolens and P. parviflorus needs glabrous; upper lobes orbicular, erect, 1-1.8 investigation. Plectranthus caldericola is not x 1-2 mm, non-glandular trichomes dense, typical of what one would expect from an FI divaricate, 2-4-celled up to 0.6 mm long, hybrid in terms of its morphology and ‘wild’ glandular trichomes absent, sessile glands hybrids of Plectranthus have proven to be scattered; lateral lobes oblong, 1-1.5 x 0.5-0.6 rarely encountered (Blake 1971: 29; Forster mm, glabrous; lower lobe ± orbicular, 3-4.5 x 1991). Further localities should be sought for 3.5- 4.5 mm, non-glandular trichomes sparse, this species in adjacent areas and the status of divaricate, 2-4-celled up to 0.3 mm long, somewhat similar plants (perhaps also from glandular trichomes absent, sessile glands putative hybridization events) at the North scattered; filaments filiform, 7-11 x c. 0.2 mm, Obelisk in New South Wales and Buchanan’s lilac, fused for 3-4 mm from base; anthers c. Fort in Queensland requires further work. 0.5 x 0.3 mm; style filiform, 8-9 mm long, Conservation status: Plectranthus caldericola lilac, bifid for c. 0.8 mm. Fruit calyces 3-3.5 is presently known only from the type locality mm long; upper lobe orbicular-ovate, 1.2-1.6 x where it is a very common plant. Although 1.5- 1.7 mm; lateral lobes lanceolate, 1.2-1.5 x this locality is within National Park, the O. 9-1 mm; lower lobes lanceolate-falcate, 1.2- plants may be subjected to trampling from 1.5 x 0.8-1 mm. Nutlets ± circular in outline, ± bushwalkers and from the occasional wildfire. flattened, 0.6-0.7 mm long, 0.6-0.7 mm wide The recommended conservation coding is and c. 0.5 mm thick, glossy brown, surface Vulnerable based on the criterion D2 (IUCN smooth. Fig. 4. 2001). Additional specimens examined: New South Wales. The Pinnacle, Jan 1993, McDonald s.n. (BRI, NSW). Etymology: The specific epithet is derived from calderus (a caldera) and cola (loving) Distribution and habitat: Plectranthus and refers to the occurrence of this species on caldericola is known only from The Pinnacle part of the Mt Warning caldera. in the Border Ranges of northern New South Wales. Plants grow on rock outcrops and 3. Plectranthus fragrantissimus P.I.Forst., pavements formed of porphyritic basalts species nova affinis P. suaveolenti S.T.Blake, between 920 and 1000 m with a shrubland sed lamina foliorum minore angustiore dominated by Leptospermum polygalifolium (lanceolato-ovata usque ovata, 10-40 x Salisb. Other species of Plectranthus that 6-25 mm non ovata usque late ovata, 30- occur sympatrically are P. graveolens and 75 x 20-60 mm), florum pedicellis multo P. parviflorus Willd. longioribus (4-5.5. mm adversum 1.5-4 mm), Forster, five new species of Plectranthus 395 cuneate to truncate; upper surface dark-green to silver-green, veins impressed, non-glandular trichomes sparseto dense, antrorseto divaricate, 6-8-celled up to 1 mm long, glandular trichomes sparse to dense; lower surface silver- green, veins raised, non-glandular trichomes dense (particularly on veins), retrorse, 6- 8-celled up to 1 mm long, glandular trichomes sparse to dense. Inflorescence up to 230 mm long, usually unbranched (rarely with two side branches); axis square in cross-section, non-glandular trichomes sparse to dense, retrorse, 2-6-celled up to 0.2 mm long, glandular trichomes scattered to sparse; bracts obovate, 1.8-2 x 1.4-2 mm, not forming a coma, non-glandular trichomes sparse to dense, antrorse to divaricate, 2-8-celled up to 0.6 mm long, glandular trichomes sparse; cymes sessile; verticillasters 6-14-flowered, 4-20 mm apart; pedicels 4-5.5 x c. 0.2 mm diameter, non-glandular trichomes sparse to Map 2. Distribution of Plectranthus caldericola (cid:9733), dense, antrorse to divaricate, 2-4-celled up P. fragrantissimus • and P. insularis A in southern to 0.2 mm long, glandular trichomes scattered Queensland and northern New South Wales. Shaded area to sparse. Flower calyces 2.5-3.5 mm long, on map indicates conservation reserves (National Parks, non-glandular trichomes scattered to sparse, Forest Reserves and Conservation Parks). antrorse to divaricate, 2-6-celled up to 0.5 mm long, glandular trichomes sparse to dense. calyce lobis inferioribus lobos laterales plus Corolla 9-10 mm long, lilac; tube 5-5.5 mm minusve aequantibus et lobis superioribus long, weakly curved at 10-20° c. 2 mm from ovatis (non subcircularibus) differens. Typus: base, slightly inflated upwards, non-glandular Queensland. Port Curtis District: State trichomes scattered, divaricate to retrorse, 2-4- Forest 316, Kroombit Tops, 16 February 1995, celled up to 0.2 mm long, glandular trichomes P.I.Forster PIF16246 (holo: BRI [2 sheets + absent; upper lobes suborbicular, erect, 1.8-2 x spirit]; iso: MEL, NE). 1.8-2 mm, non-glandular trichomes scattered Low growing herb to 30 cm high; foliage to sparse, divaricate, 2-4-celled up to 0.2 with sweetly aromatic scent when crushed, mm long, glandular trichomes scattered to clammy; non-glandular and glandular sparse; lateral lobes oblong, 1.3-1.8 x 0.6-0.8 trichomes uncoloured, sessile glands absent. mm, glabrous or as in upper lobes; lower lobe Roots thickened, fibrous. Stems square, erect oblong-ovate, 4.8-5 x 3.8-4 mm, indumentum to straggling, fleshy, the lower parts up to 4 as in upper lobes; filaments filiform, 6-8 x c. mm diameter, pink-purple, non-glandular 0.2 mm, lilac, fused for 3-4 mm from base; trichomes sparse to dense, retrorse, 2-6-celled anthers c. 0.4 x 0.3 mm; style filiform, 8-9 mm up to 0.3 mm long, glandular trichomes absent long, lilac, bifid for c. 0.3 mm. Fruit calyces or scattered to sparse. Leaves discolorous; 3.5- 4.8 mm long; upper lobe ovate, 1.5-2 x petioles 2-19 x 1-1.7 mm, channelled on 1.7-2 mm; lateral lobes lanceolate, 1.5-2 x top, non-glandular trichomes dense, retrorse, 0.8-0.9 mm; lower lobes lanceolate-falcate, 2-6-celled up to 0.8 mm long, glandular 1.5- 2.2 x c. 0.5 mm. Nutlets ± circular in trichomes sparse; laminae lanceolate-ovate to outline, ± flattened, 0.7-0.9 mm long, 0.7-0.9 ovate, fleshy to succulent, 10-40 x 6-25 mm, mm wide, 0.4-0.5 mm thick, glossy dark crenate with 7-14 teeth up to 2 mm long on brown, surface smooth. Fig. 5. each margin, widest above middle, secondary Additional specimens examined: Queensland. Port teeth sometimes present; tip acute; base Curtis District: S.F. 316 Kroombit Tops, Feb 1995, 396 Austrobaileya 8(3): 387—404 (2011) Fig. 5. Plectrantlius fragrantissimus. A. flowering stem *1. B. abaxial view of leaf x2. C. adaxial view of leaf x2. D. portion of inflorescence with two verticillasters, buds and flowers x4. E. lateral view of flower x6. F. face view of flower x9. G. pedicel and calyx x9. All from Forster PIF29770 & Halford {BRI). Del. W.Smith.