Abstract
Pelargonium hammansbergense and P. roseopetalum are described as new species. Both are deciduous geophytes with turnip-shaped tubers belonging to P. section Hoarea. These two species share spathulate petals with narrow cuneate claws. However, they differ in leaf shape, flower colour and markings on the petals. Their flower structure corresponds to that of P. aridicola, P. hirtipetalum, P. pubipetalum, P. reflexipetalum and P. tripalmatum. The seven species are compared with regard to the flower and leaf morphology, palynology and chromosome numbers. They all occur in the winter rainfall region along the west coast of South Africa. The two new species described here are illustrated and a key for the identification of the seven species with a P. aridicola flower type is included.
References
<p>Aiton, W. (1789) <em>Hortus Kewensis, Vol. 2.</em> George Nicol, London, 460 pp. https://doi.org/10.5962/bhl.title.4504</p>
<p>Alarcón, M.L., Aldasoro, J.J., Aedo, C. & Navarro, C. (2003) A new species of <em>Erodium</em> L’Hér. (Geraniaceae) endemic to Australia. <em>Botanical Journal of the Linnean Society </em>141 (2): 243–250. https://doi.org/10.1046/j.1095-8339.2003.00137.x</p>
<p>Bortenschlager, S. (1967) Vorläufige Mitteilungen zur Pollenmorphologie in der Familie der Geraniaceen und ihre systematische Bedeutung. <em>Grana Palynologica</em> 7: 400–468. https://doi.org/10.1080/00173136709430046</p>
<p>Brown, N.E. (1913) <em>Pelargonium luteolum. Kew Bulletin</em> 1913: 299. https://doi.org/10.2307/4118441</p>
<p>Compton, R.H. (1931) The Flora of the Whitehill District. <em>Transactions of the Royal Society of South Africa </em>19: 269–326. https://doi.org/10.1080/00359193109518840</p>
<p>Candolle, A.P. de (1824) Geraniaceae. <em>Prodromus systematis naturalis regni vegetabilis</em>, Vol. 1. Treuttel & Wurts, Paris, pp. 673–682.</p>
<p>Gibby, M., Hinnah, S., Marais, E.M. & Albers, F. (1996) Cytological variation and evolution within <em>Pelargonium</em> section <em>Hoarea</em> (Geraniaceae). <em>Plant Systematics and Evolution</em> 203: 111–142. https://doi.org/10.1007/BF00985241</p>
<p>Gresse, P.G. (compiler) (1997) 3319 Worcester: 1:250 000 Geological Map Series, Council for Geoscience, South Africa.</p>
<p>Gresse, P.G. & Theron, J.N. (1992) <em>The geology of the Worcester area. </em>Government Printer, Pretoria.</p>
<p>Harvey, W.H. (1860) Geraniaceae.<em> In: </em>Harvey, W.H. & Sonder, O.W. (Eds.) <em>Flora Capensis</em>. Vol. 1. Hodges, Smith & Co, Dublin, pp. 259–308.</p>
<p>Jackson, S.P. (1961) <em>Climatical atlas of Africa.</em> CCTA/CSA, Lagos.</p>
<p>Jussieu, A.L. de (1789) <em>Genera Plantarum secundum ordines naturales disposita</em>. Viduam Herissant Typographum, Parisiis, 498 pp.</p>
<p>L’Héritier de Brutellle, C.-L. (1789) Geraniaceae. <em>In: </em>Aiton, W. (Ed.) <em>Hortus Kewensis, vol. 2.</em> George Nicol, London, 460 pp. https://doi.org/10.5962/bhl.title.4504</p>
<p>Le Roux, A. (2018) <em>The vegetation ecology of the Witteberg and Dwyka Groups south of Worcester, Western Cape Province, South Africa.</em> PhD Thesis, University of South Africa, Pretoria.</p>
<p>Leistner, O.A. & Morris, J.W. (1976) Southern African place names. <em>Annals of the Cape Provincial Museums </em>12: 1–565.</p>
<p>Lessing, C.F. (1832) Genus <em>Elytropappus.</em> <em>In</em>: <em>Synopsis generum compositarum earumque dispositionis novae tentamen, monographis multarum Capensium interjectis. </em>Berolini, Berlin, pp. 344–345. https://doi.org/10.5962/bhl.title.51470</p>
<p>Marais, E.M. (1981) <em>Die taksonomiese waarde van die blom van Pelargonium (Geraniaceae). </em>Unpublished M.Sc. Thesis, University of Stellenbosch. </p>
<p>Marais, E.M. (1994) <em>Taxonomic studies in Pelargonium, section Hoarea (Geraniaceae). </em>Dissertation presented for the degree of Philosophy at the University of Stellenbosch, South Africa.</p>
<p>Marais, E.M. (1996) <em>Pelargonium tripalmatum</em> (Geraniaceae): a new species from the Richtersveld. <em>South African Journal of Botany</em> 62: 225–227. https://doi.org/10.1016/S0254-6299(15)30648-7</p>
<p>Marais, E.M. (1997a) Name changes in <em>Pelargonium, </em>section <em>Hoarea</em> (Geraniaceae). <em>South African Journal of Botany</em> 63: 68–73. https://doi.org/10.1016/S0254-6299(15)30705-5</p>
<p>Marais, E.M. (1997b) Three new species of <em>Pelargonium</em> (Geraniaceae) from Namaqualand. <em>South African Journal of Botany</em> 63: 82–89. https://doi.org/10.1016/S0254-6299(15)30707-9</p>
<p>Marais, E.M. (2000) Since the Ph.D thesis: Marais, E.M. (1994), Taxonomic studies in <em>Pelargonium</em>, section <em>Hoarea</em> (Geraniaceae). Ph. D. thesis, University of Stellenbosch, was reprinted and distributed by the Geraniaceae Group (England) in 2000, the name <em>Pelargonium vinaceum</em> E.M.Marais is considered effectively published from March 2000 (Article 29 of the International Code of Botanical Nomenclature, Greuter <em>et al. </em>1994).</p>
<p>Persoon, C.H. (1806) <em>Synopsis plantarum</em>. Vol. 2. J.G. Cottam, Tübingen.</p>
<p>Plants of the World Online (2021) Geraniaceae Juss. Kew Science. Available from: http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30001521-2 (accessed 26 May 2021)</p>
<p>Salisbury, R.A. (1806) <em>Pelargonium nummulifolium. </em>In: <em>The paradisis londinensis</em>, Vol. 1. W. Hooker, London. </p>
<p>Snijman, D. & Perry, P. (1987) A floristic analysis of the Nieuwoudtville Wild Flower Reserve, north-western Cape. <em>South African Journal of Botany</em> 53: 445–454. https://doi.org/10.1016/S0254-6299(16)31378-3</p>
<p>Thiers, B. (2021) Index Herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. [http://sweetgum.nybg.org/science/ih/]</p>
<p>Touloumenidou, T., Bakker, F.T., Marais, E.M. & Albers, F. (2004) Chromosomal evolution interpreted from the rDNA ITS phylogeny for <em>Pelargonium</em> sect. <em>Hoarea</em> (Geraniaceae). <em>In:</em> Thiede, J., Veste, M., Jürgens, N. & Metzing, D. (Eds.) <em>Succulent Plant Research in Africa: Schumania 4. Biodiversity & Ecology </em>2: 93–106.</p>
<p>Wagensommer, R.P. & Venanzoni, R. (2021) <em>Geranium lucarinii sp. nov. </em>and re-evaluation of<em> G. kikianum </em>(Geraniaceae). <em>Phytotaxa</em> 489 (3): 252–262. https://doi.org/10.11646/phytotaxa.489.3.2</p>
<p>Alarcón, M.L., Aldasoro, J.J., Aedo, C. & Navarro, C. (2003) A new species of <em>Erodium</em> L’Hér. (Geraniaceae) endemic to Australia. <em>Botanical Journal of the Linnean Society </em>141 (2): 243–250. https://doi.org/10.1046/j.1095-8339.2003.00137.x</p>
<p>Bortenschlager, S. (1967) Vorläufige Mitteilungen zur Pollenmorphologie in der Familie der Geraniaceen und ihre systematische Bedeutung. <em>Grana Palynologica</em> 7: 400–468. https://doi.org/10.1080/00173136709430046</p>
<p>Brown, N.E. (1913) <em>Pelargonium luteolum. Kew Bulletin</em> 1913: 299. https://doi.org/10.2307/4118441</p>
<p>Compton, R.H. (1931) The Flora of the Whitehill District. <em>Transactions of the Royal Society of South Africa </em>19: 269–326. https://doi.org/10.1080/00359193109518840</p>
<p>Candolle, A.P. de (1824) Geraniaceae. <em>Prodromus systematis naturalis regni vegetabilis</em>, Vol. 1. Treuttel & Wurts, Paris, pp. 673–682.</p>
<p>Gibby, M., Hinnah, S., Marais, E.M. & Albers, F. (1996) Cytological variation and evolution within <em>Pelargonium</em> section <em>Hoarea</em> (Geraniaceae). <em>Plant Systematics and Evolution</em> 203: 111–142. https://doi.org/10.1007/BF00985241</p>
<p>Gresse, P.G. (compiler) (1997) 3319 Worcester: 1:250 000 Geological Map Series, Council for Geoscience, South Africa.</p>
<p>Gresse, P.G. & Theron, J.N. (1992) <em>The geology of the Worcester area. </em>Government Printer, Pretoria.</p>
<p>Harvey, W.H. (1860) Geraniaceae.<em> In: </em>Harvey, W.H. & Sonder, O.W. (Eds.) <em>Flora Capensis</em>. Vol. 1. Hodges, Smith & Co, Dublin, pp. 259–308.</p>
<p>Jackson, S.P. (1961) <em>Climatical atlas of Africa.</em> CCTA/CSA, Lagos.</p>
<p>Jussieu, A.L. de (1789) <em>Genera Plantarum secundum ordines naturales disposita</em>. Viduam Herissant Typographum, Parisiis, 498 pp.</p>
<p>L’Héritier de Brutellle, C.-L. (1789) Geraniaceae. <em>In: </em>Aiton, W. (Ed.) <em>Hortus Kewensis, vol. 2.</em> George Nicol, London, 460 pp. https://doi.org/10.5962/bhl.title.4504</p>
<p>Le Roux, A. (2018) <em>The vegetation ecology of the Witteberg and Dwyka Groups south of Worcester, Western Cape Province, South Africa.</em> PhD Thesis, University of South Africa, Pretoria.</p>
<p>Leistner, O.A. & Morris, J.W. (1976) Southern African place names. <em>Annals of the Cape Provincial Museums </em>12: 1–565.</p>
<p>Lessing, C.F. (1832) Genus <em>Elytropappus.</em> <em>In</em>: <em>Synopsis generum compositarum earumque dispositionis novae tentamen, monographis multarum Capensium interjectis. </em>Berolini, Berlin, pp. 344–345. https://doi.org/10.5962/bhl.title.51470</p>
<p>Marais, E.M. (1981) <em>Die taksonomiese waarde van die blom van Pelargonium (Geraniaceae). </em>Unpublished M.Sc. Thesis, University of Stellenbosch. </p>
<p>Marais, E.M. (1994) <em>Taxonomic studies in Pelargonium, section Hoarea (Geraniaceae). </em>Dissertation presented for the degree of Philosophy at the University of Stellenbosch, South Africa.</p>
<p>Marais, E.M. (1996) <em>Pelargonium tripalmatum</em> (Geraniaceae): a new species from the Richtersveld. <em>South African Journal of Botany</em> 62: 225–227. https://doi.org/10.1016/S0254-6299(15)30648-7</p>
<p>Marais, E.M. (1997a) Name changes in <em>Pelargonium, </em>section <em>Hoarea</em> (Geraniaceae). <em>South African Journal of Botany</em> 63: 68–73. https://doi.org/10.1016/S0254-6299(15)30705-5</p>
<p>Marais, E.M. (1997b) Three new species of <em>Pelargonium</em> (Geraniaceae) from Namaqualand. <em>South African Journal of Botany</em> 63: 82–89. https://doi.org/10.1016/S0254-6299(15)30707-9</p>
<p>Marais, E.M. (2000) Since the Ph.D thesis: Marais, E.M. (1994), Taxonomic studies in <em>Pelargonium</em>, section <em>Hoarea</em> (Geraniaceae). Ph. D. thesis, University of Stellenbosch, was reprinted and distributed by the Geraniaceae Group (England) in 2000, the name <em>Pelargonium vinaceum</em> E.M.Marais is considered effectively published from March 2000 (Article 29 of the International Code of Botanical Nomenclature, Greuter <em>et al. </em>1994).</p>
<p>Persoon, C.H. (1806) <em>Synopsis plantarum</em>. Vol. 2. J.G. Cottam, Tübingen.</p>
<p>Plants of the World Online (2021) Geraniaceae Juss. Kew Science. Available from: http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30001521-2 (accessed 26 May 2021)</p>
<p>Salisbury, R.A. (1806) <em>Pelargonium nummulifolium. </em>In: <em>The paradisis londinensis</em>, Vol. 1. W. Hooker, London. </p>
<p>Snijman, D. & Perry, P. (1987) A floristic analysis of the Nieuwoudtville Wild Flower Reserve, north-western Cape. <em>South African Journal of Botany</em> 53: 445–454. https://doi.org/10.1016/S0254-6299(16)31378-3</p>
<p>Thiers, B. (2021) Index Herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. [http://sweetgum.nybg.org/science/ih/]</p>
<p>Touloumenidou, T., Bakker, F.T., Marais, E.M. & Albers, F. (2004) Chromosomal evolution interpreted from the rDNA ITS phylogeny for <em>Pelargonium</em> sect. <em>Hoarea</em> (Geraniaceae). <em>In:</em> Thiede, J., Veste, M., Jürgens, N. & Metzing, D. (Eds.) <em>Succulent Plant Research in Africa: Schumania 4. Biodiversity & Ecology </em>2: 93–106.</p>
<p>Wagensommer, R.P. & Venanzoni, R. (2021) <em>Geranium lucarinii sp. nov. </em>and re-evaluation of<em> G. kikianum </em>(Geraniaceae). <em>Phytotaxa</em> 489 (3): 252–262. https://doi.org/10.11646/phytotaxa.489.3.2</p>