A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae) Author Knapp, Sandra https://orcid.org/0000-0001-7698-3945 Natural History Museum, Cromwell Road, London SW 7 5 BD, UK s.knapp@nhm.ac.uk Author Saerkinen, Tiina https://orcid.org/0000-0002-6956-3093 Royal Botanic Garden Edinburgh, 20 A Inverleith Row, Edinburgh EH 3 5 LR, UK Author Barboza, Gloria E. https://orcid.org/0000-0003-1085-036X Instituto Multidisciplinario de Biologia Vegetal (CONICET-Universidad Nacional de Cordoba), Casilla de Correo 495, 5000 Cordoba, Argentina text PhytoKeys 2023 2023-08-29 231 1 342 http://dx.doi.org/10.3897/phytokeys.231.100894 journal article http://dx.doi.org/10.3897/phytokeys.231.100894 1314-2003-231-1 0D762CF99C605B04AF072C867EEB1488 24. Solanum huayavillense Del Vitto & Peten., Kurtziana 24: 167. 1995. Figs 3E , 74 , 75 Solanum pachyantherum Bitter, Repert. Spec. Nov. Regni Veg. 11: 206. 1912., nom. illeg., non Solanum pachyantherum Witasek (1910). Type. Bolivia. Tarija: Huayavilla, 6 Dec 1903, K. Fiebrig 2507 (lectotype, designated by Barboza et al. 2013 , pg. 250: CORD [CORD00004254]; isolectotype: SI [003330, acc. # 055986]). Type . Based on Solanum pachyantherum Bitter. Figure 74. Solanum huayavillense A flowering branch B eglandular trichome of the leaf C inflorescence D calyx E eglandular trichome of the calyx F flower G sector of dissected flower H stamen, dorsal view I stamen, ventral view J eglandular trichome of the filament K gynoecium ( A-K Barboza et al. 2255 ). Illustration by P. Peralta. Previously published in Barboza et al. (2013 : 250). Description. Erect perennial herbs or subshrubs 0.8-1 m high. Stems terete, glabrous to moderately pubescent with eglandular, simple uniseriate 2-6-celled trichomes to 0.7 mm long, these spreading and often moniliform, forming spinose processes on older stems; new growth moderately to densely pubescent with eglandular simple uniseriate trichomes 0.5-0.7 mm long; bark of older stems glabrescent, pale yellowish tan. Sympodial units difoliate, the leaves geminate, equal in size and shape, or one leaf of the pair slightly smaller. Leaves simple, the blades 4.5-15 cm long, 1.5-6 cm wide, elliptic to broadly elliptic, widest at the middle, membranous, concolorous; adaxial surfaces glabrous to sparsely and evenly pubescent with eglandular simple uniseriate trichomes to 1 mm long; abaxially glabrous to sparsely pubescent with eglandular simple uniseriate trichomes along the veins; principal veins 5-8 pairs, drying yellowish green on abaxially surfaces; base attenuate onto the petiole and the leaves sessile; margins entire, with sparse unicellular hooked trichomes ca. 0.1 mm long; apex acute to more commonly acuminate; petiole absent or occasionally to 0.2 cm long. Inflorescences internodal, several times branched, to 8 cm long, with 20 to 40 flowers, moderately pubescent with eglandular simple uniseriate trichomes to 0.5 mm (even if stems and leaves are glabrous the inflorescence is pubescent); peduncle 1-3 cm long; pedicels 0.6-0.7 cm, ca. 0.5 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, tapering, deflexed to spreading at anthesis, sparsely to moderately pubescent with eglandular simple uniseriate trichomes like those of the rest of the inflorescence, articulated at the base; pedicel scars irregularly spaced 0.5-1.5 mm apart. Buds globose to broadly ellipsoid, the corolla strongly exserted from the calyx tube before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 0.5-1 mm long, conical from the expanded apex of pedicel, the lobes 1-1.5 mm long, deltate with rounded tips, in live plants somewhat expanded and globose, pubescent with eglandular simple uniseriate trichomes like the pedicels and inflorescence axis. Corolla 0.9-1.2 cm in diameter, pale, clear yellow, stellate, lobed 3/4 of the way to the base, the lobes 4-5 mm long, 2-3 mm wide, reflexed at anthesis, glabrous adaxially, minutely papillate abaxially especially at the tips and along the margins. Stamens 5, equal; filament tube ca. 0.5 mm long; free portion of the filaments 0.25-0.5 mm long, densely pubescent with weak, tangled simple uniseriate trichomes adaxially; anthers 2.5-3 mm long, 1.5-1.75 mm wide, broadly ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 5.5-6.5 mm long, straight, exserted beyond the anther cone, densely pubescent in the lower half with simple 2-3-celled uniseriate trichomes; stigma minutely capitate, merely the slightly expanded style apex, minutely papillate, green in live plants. Fruit a globose berry, 0.4-0.6 cm in diameter, green when mature, the pericarp thin and translucent, matte, glabrous; fruiting pedicels 0.8-1.2 cm long, ca. 0.5 mm in diameter at the base, not markedly woody, deflexed or spreading, not persistent; fruiting calyx not accrescent, somewhat spreading. Seeds 6-8 per berry, 1-1.5 mm long, 1-1.5 mm wide, teardrop shaped but not markedly flattened, pale yellowish tan, the surfaces minutely pitted, the testal cells sinuate in outline. Stone cells absent (Argentina) or 4 (Bolivia), ca. 0.4 mm in diameter, 2 situated apically and 2 centrally. Chromosome number: not known. Figure 75. Solanum huayavillense A habit B habit C leaf pubescence (abaxial surface) D flowers at anthesis ( A, B-D Barboza et al. 3531 C Barboza et al. 3532 ). Photos by S. Knapp. Distribution (Fig. 76 ). Solanum huayavillense is narrowly distributed in southern Bolivia (Depts. Chuquisaca, Tarija) and Argentina (Depts. Catamarca, Jujuy, Salta, Tucuman ). Figure 76. Distribution map of Solanum huayavillense . Ecology and habitat. Solanum huayavillense occurs in the understory of cloud forest ( 'yungas' ) either in the understorey proper or at edges of clearings or treefalls, from 1,200 to 2,950 m elevation. Common names and uses. None recorded. Preliminary conservation status ( IUCN 2022 ). Least Concern [LC]. EOO = 80,000 km2 [LC]; AOO = 92 km2 [EN]. Solanum huayavillense is relatively common where it is found in at least two protected areas in Argentina (Parque Nacional Baritu and Parque Nacional Calilegua). Discussion. Solanum huayavillense is unique in the morelloid clade, and unusual in Solanum outside of the tomatoes, in having pale yellow, rather than white or violet, flowers. The yellow of S. huayavillense flowers is paler than that of the tomatoes (see Peralta et al. 2008 ) but still clearly yellow. It is not known whether this yellow is due to carotenoid or flavonoid content, as no chemical analysis has been undertaken. Vegetatively and in fruit S. huayavillense resembles S. zuloagae from slightly lower elevations in Argentina. The two species share lax growth, with long branches scrambling over adjacent vegetation, thin membranous leaves with sparsely ciliate margins and tiny flowers with short, stubby anthers. The flowers of S. huayavillense are slightly smaller than those of S. zuloagae (0.9-1.2 cm in diameter versus 1.2-1.8 cm in diameter) and differ in colour (yellow versus clear white). The calyx tube is longer than the lobes in S. huayavillense and somewhat urceolate (Fig. 75D ), while in S. zuloagae the lobes are longer than the tube, and often unequal in size.