Grammosolen (Solanaceae - Anthocercideae) Revisited L
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Swainsona 33: 11–29 (2020) © 2020 Board of the Botanic Gardens & State Herbarium (Adelaide, South Australia) Grammosolen (Solanaceae - Anthocercideae) revisited L. Haegi State Herbarium of South Australia, GPO Box 1047, Adelaide, South Australia 5001 Email: [email protected] Abstract: Study of newly collected specimens from beyond the former known geographical range of Grammosolen, together with consideration of newly published results of molecular phylogenetic studies in tribe Anthocercideae have led to an expanded concept of the genus. The rare G. archeri Haegi is newly described from far south-eastern Western Australia; G. odgersii is transferred from Cyphanthera; and the known range of G. truncatus, formerly regarded as an endemic South Australian species, is extended to adjacent far eastern Western Australia. Keywords: Grammosolen, Cyphanthera, Anthocercideae, Solanaceae, taxonomy, new species, intergeneric hybrids Introduction Materials and Methods Grammosolen Haegi was first described as a new genus This study is based on investigations carried out over in the context of a monographic study leading to the several decades, commencing in the first instance as re-instatement of the distinctively Australasian tribe part of the subject of a PhD thesis (Haegi 1983). It Anthocercideae G.Don (Haegi 1981, 1983). The study is based on detailed morphological examination of all led to the recognition of 31 species in seven genera– available herbarium material in Australian and relevant Anthocercis Labill., Anthotroche Endl., Crenidium Haegi, overseas herbaria as well as many specimens collected Cyphanthera Miers, Duboisia R.Br., Grammosolen and in the course of the study. Measurements of each Symonanthus Haegi (Haegi 1981, 1983). Grammosolen character used in the descriptions were, where possible, was established to accommodate two closely related, taken from a sample of between 20 and 30 specimens distinctive species: G. dixonii (F.Muell. & R.Tate) selected to represent the whole geographic range. Haegi (formerly mistakenly assigned to Newcastelia Characters which showed variability were measured for F.Muell. in family Verbenaceae) and G. truncatus (Ising) at least two organs on each specimen in the sample and Haegi, originally described as a species of Anthotroche. in the case of leaves, the dimensions of the largest as One new species has since been described in each of well as of two or three of those judged to be close to Anthocercis (Macfarlane & Wardell-Johnson 1996) and the mode were recorded. Dried material was used for Duboisia (Craven et al. 1995), bringing the total to 33 all measurements, except the flowers which were either softened in a weak solution of detergent and hot water species in the tribe. or for which spirit material collected in the course of the study was used. Leaves were measured to the nearest Grammosolen has been known only from the state of millimetre with a ruler, while most other organs were South Australia. Additional collecting in more remote measured to the nearest ½ millimetre using a low-power parts of Australia has since not only extended the known stereo-microscope fitted with an ocular micrometer, at distribution in South Australia but has also brought to 10× magnification. Larger hairs (1.0–2.5 mm long) light specimens from Western Australia. Some of these were measured in this way to the nearest 0.05 mm; represent a range extension of G. truncatus a relatively smaller hairs (0.025–0.075 mm) were measured to the short distance across the border from South Australian nearest 0.025 mm at 40× magnification. Indumentum populations nearby. Others, confined to a small area terminology follows Haegi (1991). much further west, inland from Cape Arid on the southern coast, have proved to be not readily assignable Chromosome numbers were investigated for three to either existing species, or to any other species in species from the study of meiosis in pollen mother cells. the tribe. These specimens are consistently distinct To date it has not been possible to obtain living material in several features, including their small, orbicular- of the fourth species, G. archeri. Flower buds collected reniform to obcordate leaves and in their smaller in the field were placed immediately in a mixture of 3 flowers and fruits. The new species Grammosolen parts of ethanol to 1 part of glacial acetic acid (mixed archeri, endemic to south-eastern Western Australia, is in situ). After 24 hours the buds were transferred to described here on the basis of these specimens. 100% ethanol, kept in cool conditions and finally Published online: 31 Jan. 2020 • flora.sa.gov.au/swainsona ISSN 2206-1649 (Print) • ISSN 2206-1657 (Online) L. Haegi Swainsona 33 (2020) stored in temperatures below 0°C. Standard anther More recently, molecular phylogenetic studies of the squash techniques (Darlington & La Cour 1970) Anthocercideae and near relatives, analysing sequence were used to obtain microscope slide preparations for data from four chloroplast DNA regions — ndhF and observing chromosomes at meiosis. The preparation trnL/F (Garcia & Olmstead 2003), as well as trnS-G was examined with a compound light microscope at and matK (Clarkson et al. 2004) — have provided new up to 1,000× magnification, sometimes with the aid of evidence for assessing the affinities and relationships phase contrast illumination. The results were recorded of these genera. It is now generally accepted that using a camera lucida device fitted to the microscope. together with the genus Nicotiana, these genera make up a distinctive grouping within the family, for the Although it can be caused by other factors (such as time being treated as subfamily Nicotianoideae. This is environmental ones) sterility of pollen is a useful guide confirmed and placed within the context of an overview to the occurrence of hybridisation, especially when of the molecular phylogeny of the Solanaceae as a whole pollen from possible parents sampled at the same time by Olmstead et al. (2008). There is strong support proves highly viable. Stainability of pollen was tested as for continued recognition of Tribe Anthocercideae an indicator of viability using 0.5% lactophenol cotton (Clarkson et al. 2004), perhaps with some uncertainty blue, which stains cytoplasm. Pollen from a single about the placement of the genus Symonanthus, whose mature anther from each of several different flowers relationships with the remainder of the Anthocercideae from recently collected herbarium specimens was on the one hand and Nicotiana on the other, remain teased out into a drop of stain on a microscope slide, unresolved (Olmstead et al. 2008). Within the a coverslip was applied and the preparation examined Anthocercideae these molecular phylogenetic studies with a compound microscope, with all grains present provide partial support for the morphologically-based scored. generic classification (including continued generic recognition of Grammosolen) but also provide evidence The composite distribution map (Fig. 3) was prepared for a different approach to the circumscription of utilising point distributional data from the AVH, some genera. On the basis of that evidence C. odgersii viewed in the ALA portal (accessed 3 July 2019), is demonstrated, as part of a highly supported downloaded and edited to remove misidentified and “Grammosolen clade”, to have a closer relationship with misplotted duplicate records. The map as presented the two known species of Grammosolen than to all the Cyphanthera was prepared using QGIS v. 3.2.0–Bonn, with the other species of (Garcia & Olmstead 2003; Clarkson et al. 2004). map outline and features (coastline, sand-ridge and lakes layers) from GEODATA TOPO 250K series 3 The evidence from molecular studies prompts a re- Topographic data (Geoscience Australia 2018, accessed assessment of the diagnostic value of characters found 5 February 2018). in Grammosolen and Duboisia/Cyphanthera. Inclusion of Cyphanthera odgersii in the Grammosolen clade Generic placement of Cyphanthera odgersii on molecular grounds is consistent with the shared occurrence of erect, hippocrepiform anthers dehiscing by a hippocrepiform slit on the abaxial face (Figs 1, When it was described, Grammosolen was unique 10, 11). This may prove to be a synapomorphy for the within the Anthocercideae for the occurrence of expanded genus (together with the otherwise distinctive multangulate hairs (in particular on the exterior of the genus Anthotroche). In the apparent plesiomorphic corolla lobes), a di- or tri-dynamous androecium of five condition found throughout Duboisia (four species) and fertile stamens and a gametic chromosome number of the remainder of Cyphanthera (eight species) the anthers n=56. At that time attention was drawn to some close are sub-reniform, oblique (twisted towards the vertical similarities between Cyphanthera odgersii (F.Muell.) and tilted abaxially) and dehisce by a semicircular slit Haegi and the two known species of Grammosolen. along the distal margin (for example as in C. racemosa Verticillately-branched trichomes are found in both (F.Muell.) Haegi – Fig. 1). While a dense indumentum C. odgersii and G. dixonii, while all three species share of dendritic hairs occurs in some species of Cyphanthera, a spike-like inflorescence and, perhaps most notably, the very dense woolly indumentum found in C. odgersii hippocrepiform anthers (Haegi 1983). These last is unique in the genus (Haegi 1991). Similar hair- two features are not otherwise found in Cyphanthera coverings are, however,