Plectranthus laetus P.I.Forst. and P. ventosus 
P.I.Forst. (Lamiaceae), new species from 
Cape York Peninsula, Queensland 
Paul I. Forster 
Summary 
Forster, P.I. (2015). Plectranthus laetus P.I.Forst. and P. ventosus P.I.Forst. (Lamiaceae), new 
species from Cape York Peninsula, Queensland. Austrobaileya 9(3): 431-438. Two new species of 
Plectranthus are described from Cape York Peninsula: P. laetus P.I.Forst. from Orchid Creek Station 
and P. ventosus P.I.Forst. from the Melville Range at Cape Melville National Park. Both species occur 
on granite substrates within or adjacent to rainforests. 
Key Words: Lamiaceae, Plectranthus , Plectranthus laetus , Plectranthus ventosus , Australia flora, 
Queensland flora. Cape Melville, Orchid Creek, new species, taxonomy, distribution maps. 
P.I.Forster, Queensland Herbarium, Department of Science, Information Technology and Innovation, 
Brisbane Botanic Gardens, Mt Coot-tha Road, Toowong, Queensland 4066, Australia. Email: Paul. 
For ster @dsit i. qld. gov. au 
Introduction 
Ongoing botanical exploration of remote 
areas of Cape York Peninsula continues to 
reveal vascular plants that are new to science. 
A further two species of Plectranthus 
L.Her. are described here, both discovered 
in previously unsurveyed localities on the 
tops of mountains or ridges, and in habitats 
akin to the ‘sky island’ concept discussed 
previously Forster (2014). In each case, 
access to the localities was by helicopter. 
The description of these new species brings 
to 15, the number of species of Plectranthus 
now recognised for the Cape York Peninsula 
bioregion (https: //data. qld. gov.au/dataset/ 
bioegeographic-subregions-queensland). The 
species previously recognised are P. apreptus 
S.T.Blake, P. apricus P.I.Forst., P. arenicola 
P.I.Forst., P. batianoffii P.I.Forst., P. congestus 
R.Br., P. dumicola P.I.Forst., P. excelsus 
P.I.Forst., P. foetidus Benth., P. megadontus 
P.I.Forst., P. mirus S.T.Blake, P. pulchellus 
P.I.Forst., P. scutellarioides (L.) R.Br. and P. 
venustus P.I.Forst.; ten of the overall total are 
endemic. 
Accepted for publication 23 July 2015 
Materials and methods 
Fieldwork was undertaken in north 
Queensland to procure fresh material 
for specimens and cultivation enabling 
observation of variation in morphology and 
phenology. The subsequent descriptions 
and observations are based on these recent 
collections and other earlier collections in the 
Queensland Herbarium (BRI). 
Taxonomy 
Plectranthus laetus P.I.Forst., sp. nov. with 
affinity to P. pulchellus but differing in the 
orange sessile glands (versus yellow), the 
verticillasters with fewer flowers (6-10 versus 
12-16), the flowers with corollas that are 
strikingly blue-purple (versus light purple) 
and the larger calyces. Typus: Queensland. 
Cook District: Orchid Creek Station, 
Coffee Scrub; SW of Lockhart River, Cape 
York Peninsula, 30 April 2014, P.I. Forster 
PIF41138 & S.L. Thompson (holo: BRI; iso: 
CNS, MEL, NSW distribuendi ). 
Perennial herb, stems erect to 50 cm high; 
foliage scentless when crushed, not clammy; 
non-glandular and glandular trichomes 
uncoloured, non-glandular trichomes without 
prominent raised bases, sessile glands 
8-celled, orange. Roots fibrous, somewhat 
