Notes on the genus Ophryosporus (Asteraceae, Eupatorieae) in Chile

Abstract Ophryosporus Meyen is reviewed for Chile and an updated species list for the country based on herbarium records and literature review is presented. A key to the Chilean species is provided and a distribution range of taxa is indicated based on herbarium records and our own collections. We include several lectotypifications as well as an epitypification of Ophryosporus hoppii. The presence of two species, O. hoppii and O. floribundus, formerly accepted for Chile, is questioned and their actual distribution discussed.


Introduction
During field work and specimens determination as part of the collaborative research centre 1211 (http://crc1211.uni-koeln.de) -"Earth, Evolution at the Dry Limit", we noted inconsistencies in the literature regarding the taxonomy and nomenclature of Ophryosporus Meyen.
Ophryosporus, currently with 41 accepted species, is distributed in South America and is disjunct between the Andes from Colombia to Chile and the Atlantic Forest in southern Brazil and northern Argentina (King and Robinson 1972b). The plants are (sometimes scandent) shrubs, with usually opposite secondary branching and opposite or alternate leaves, often in fascicles. The inflorescences are corymbose or thyrsoid (Hind and Robinson 2007). The genus is further characterized by reduced anther appendages, clavate style branches, a pronounced carpopodium and distinct asymmetrical cypsela base (King and Robinson 1972a). In Chile, eight shrubby species are currently recognized Rodriguez et al. 2018) and they are distributed along the coast of northern Chile as well as along the Andean Cordillera, separated by the hyper arid absolute desert (Fig. 1).
An important revision of the Eupatorieae, including the genus Ophryosporus, was published by Robinson (1906). This work maintained two sections in the genus, section Euophryosporus including O. triangularis and O. paradoxus (Hook. & Arn.) B.D.Jacks., also a Chilean species with short internodes and thyrsoid panicles, and section Ophryochaeta B.L. Rob., including 15 species with opposite leaves, well developed internodes and capitula largely in panicles or axillary cymes. Subsequent works included some new combinations and descriptions of new species, enlarging the genus to 29 species (King and Robinson 1972a), and further additions from the genus Piqueria Cav. brought the total to 38 species (King and Robinson 1972b). Apart from an unpublished thesis by Plos (2012), and several lectotypifications by Plos and Sancho (2013), no recent revision for the group exists.
We were able to make extensive collections of Ophryosporus in Chile over a period of three years. Our survey confirmed six of the eight species reported for the country by Rodriguez et al. (2018), Luebert et al. (2007) and Zuloaga et al. (2008). We present here an updated species list of Ophryosporus in Chile with a detailed account of their nomenclature and distribution, and include a key for species identification.

Methods
Field work was carried out in northern Chile and southern Peru between October 2016 and September 2019. The principal area of distribution of the Chilean species of Ophryosporus was covered, ranging from Valparaíso (33.05°S, type locality of O. paradoxus) to Arica (18.45°S) along the coast, and corresponding latitudes in the Andean cordillera of Chile. In Peru, sporadic collecting took place between Azángaro (14.92°S, type locality of O. heptanthus (Schultz-Bip. ex Wedd.) R.M. King & H.Rob.), Ollantaytambo (13.25°S), and in the vicinity of Lima (12°S). A total of 82 herbarium numbers were collected (Suppl. material 1: Table S1). Vouchers were deposited at the herbaria of Bonn, Germany (BONN), the Universidad de La Serena, Chile (ULS), the Universidad de Chile, Santiago (EIF) and the University of San Marcos, Lima (USM).
Specimens from the herbarium at Santiago (SGO), Leiden (L), Field Museum of Natural History (F), and Stockholm (S) were critically revised and geo-referenced to create a distribution map ( Fig. 1; Suppl. material 1: Table S1). In addition, we used virtual herbaria to locate type material and online images of these were consulted where available.
Scanning Electron Microscope (SEM) images were taken of the cypselae and pappus of all taxa in question (Fig. 2). Cypselae obtained from herbarium specimens were mounted on aluminium stubs using conductive carbon cement (Leit-C, PLANO, Wetzlar, Germany) and sputter coated with gold in a sputter-coater (SCD 040, Balzers Union, Liechtenstein) for 3 minutes. Images were taken with a Stereoscan 200 electron microscope (Cambridge, England) at 15 kV.  (King and Robinson 1972b;Brako and Zarucchi 1993), likely due to the type collection label ("Peruvia meridionalis..."). However, the localities mentioned there ("...Cobija, Iquiqui et Arica") are now situated in Chile, and all other reports originate from the coastal zone around Tocopilla (Johnston 1932;Jaffuel 1936) and therefore Luebert et al. (2007) considered it a Chilean endemic. We hereby extend the distribution of the species to include the populations from the coastal area between Río Loa and Iquique, previously referred to as O. floribundus Pinto and Luebert 2009). See discussion below under the latter species.   (CONC). It is possible, that having collected both specimens at the same locality where they occur sympatrically, Zöllner mistook them for a single species and only later at the two herbaria they were identified as belonging to two distinct taxa. We could not have access to the latter material at CONC, but we assume that it corresponds either to O. heptanthus or O. pinifolius. This peculiar species is known only from three localities north of the town of Paposo (Johnston 1929 . This is the southernmost species of Ophryosporus in Chile, distributed from the region Metropolitana de Santiago northward to the region Atacama. This species is not strictly limited to the coast but also occurs further inland, for example in the Cuesta Las Chilcas or Andacollo.

Our
Ophryosporus paradoxus is a very distinct species that can be differentiated from O. triangularis by its larger, lanceolate and rather papery leaves with strongly lobed margins, as opposed to the small, triangular, slightly fleshy leaves with revolute margins in O. triangularis. The secondary inflorescences are thyrsoid, emerge terminally and produce florets with white corollas and a pappus of white setae up to c. 3 mm long. Ophryosporus pinifolius has an inconspicuous pappus that consists of minute squamellae. Its leaves are extremely variable and range from linear-lanceolate with entire margins to irregularly dentate ones. It is one of two Andean species in the genus known to occur in Chile. Based on herbarium records, its distribution is centered in the northern regions of Tarapacá and Arica y Parinacota where it is widespread (Fig. 1).  -15, 19.730253S, 69.218684W, 2956m, 26 Mar 2017, F.F. Merklinger & A. Stoll 2017cuesta Usmagama, km 3.9, 19.730154S, 69.217046W, 3050 m, 28 Oct 2016, F. Luebert & T. Böhnert 3452 (BONN, ULS); Usmagama, road from Usmagama to Limacsina, 19.78771S, 69.207368W, 2434m, 26 Mar 2017, F.F. Merklinger & A. Stoll 2017quebrada de Parca, 19.985261S, 69.098117W, 3261 m, 22 Mar 2017, F.F. Merklinger & A. Stoll 2017. Notes. This species is widespread and more or less continuously distributed along the coast of northern Chile. The southernmost localities where it was observed during our study were at the southern edge of the Río Limarí, where its range overlaps with that of Ophryosporus paradoxus. The northern end of its distribution appears to be the Río Loa. North of Paposo, at Aguada del Panul, it grows sympatrically with O. johnstonii, to which it bears close morphological resemblance. However, O. triangularis is identified by its slightly larger leaves, which are grouped in alternating fascicles, are shortly petiolate, triangular with a cuneate base and an acute apex, and reaching about 3-5 × 5-15 mm as opposed to much smaller leaves in O. johnstonii, which reach only c. 1-3 × 3-5 mm. Leaf-size is, however, extremely variable, and plants that grow in more humid conditions often possess larger leaves. The leaf margins of O. triangularis are regularly lobed to dentate and revolute. The inflorescences are spikelike, and the capitula are pedunculated. The spike-like inflorescences appear somewhat denser than in O. johnstonii, and, in this latter species, the capitula are sessile. Its florets have a white corolla, sometimes with a violet taint. The pappus is formed by whitish-Three of them were collected by R. Pinto in the late 1990s at three coastal localities in northern Chile, Alto Chipana, Punta Lobos and Punta Gruesa (Pinto, s.n., SGO 142948, SGO 142949 and SGO 142950). Recent field work at the coastal localities has not resulted in any collections that match the type of O. floribundus. Rather we found plants that we identified as O. anomalus, another species that has been reported for this area (Johnston 1932) and has been only sporadically collected since. The type of O. floribundus has opposite, solitary leaves and long internodes of about 3-4 cm in length. The type of O. anomalus has crowded leaves that are borne in fascicles and with very short internodes. The leaves of the Chilean coastal specimens assigned to O. floribundus vary in size and shape, some corresponding well to the type of O. anomalus being narrowly oblanceolate and with entire margins and an obtuse apex, others becoming more broadly lanceolate to triangular with dentate margins and an acute apex thus remotely resembling O. floribundus but actually more similar to those of O. triangularis. On younger shoots the leaves appear more or less opposite but generally they are borne in fascicles. This taxon was originally described as a new genus and species, Trychinolepis hoppii (Robinson 1928: 6), because of its irregularly lobed, squamellate pappus, which resembled that of the West Indian genus Phania, even though a habitual resemblance to the genus Ophryosporus was stated by the author (Robinson 1928). Subsequent analyses led to this monotypic genus to be allocated to Ophryosporus, because the pappus remained the only difference with other species of Ophryosporus (King and Robinson 1972a).