Synopsis of Ecuadorian Pterichis (Orchidaceae)

A taxonomic synopsis of the orchid genus Pterichis in Ecuador is presented. All national representatives of this genus are characterized and their floral segments are illustrated. Four new species and two new varieties are described. An updated key to Ecuadorian Pterichis is provided. Plants of the genus are growing mostly as terrestrial herbs at the altitude of 2,300–4,110 m. Often two or more species co-occur in the area of 25 × 25 km. Their occurrence was reported from three ecoregions—the Eastern Cordillera real montane forests, the Northern Andean páramo and the Northwestern Andean montane forests. Seven Ecuadorian Pterichis are endemic.


INTRODUCTION
Amazonia and the Andes are some of the richest diversity hotspots in the world Antonelli et al., 2018). An extraordinary number of rare and endemic species is observed especially in the area where the two regions meet-the Tropical Andes. This hotspot extends from western Venezuela to northern Argentina and Chile, and incorporates significant part of territories of Colombia, Ecuador, Peru, and Bolivia. At the same time this is one of the most endangered ecoregions on the planet (Mittermeier et al., 1999), with a large portion of its landscape having been transformed. The fertile inter-Andean valleys of Colombia and Ecuador, are the most degraded as a result of agriculture and urbanization (Zador, 2015). The further habitat loss constitute a serious threat to numerous orchid genera (Hirtz, 2011).
Recognizing species composition is essential to preserve wildlife by identifying areas important for biodiversity and ecosystem services (Sofo, 2011;Casetta, Marques da Silva & Vecchi, 2019). For that reason, taxonomists are continuously publishing articles not only introducing the novelties in local biota, but also more comprehensive articles presenting concepts of particular plant or animal group (Ormerod, 2018;Damián Parizaca & Torres Montenegro, 2018). Orchidaceae and Asteraceae, with a rate of 500 new species being described each year (Chase et al., 2015), are among the most problematic groups to work with. of these facilities. Only material from AAU was loaned. Herbaria acronyms used in this article follow Thiers (2020). A total of over 100 Ecuadorian collections of Pterichis were examined.
The form of the leaf (if present) as well as the length and the surface of the scape were studied in the beginning. The assessment of the vegetative structures included also the tubular sheaths on the scape and the elements of the inflorescence (e.g., form of the floral bracts and ovaries). The perianth segments were observed after softening flowers in boiling water using a stereoscopic microscope. A database of original diagnoses and illustrations published by authors of particular taxa was created.
Morphological features presented in this study were compiled based on Ecuadorian material. The information provided on herbarium specimens labels was used for georeferencing. Distribution maps were prepared using ArcGIS 9.3 (Esri, Redlands, CA, USA). Species richness was calculated using DIVA-GIS (Hijmans et al., 2001). The concept of ecoregions follows Olson et al. (2001).

Nomenclature
The electronic version of this article in portable document format will represent a published work according to the International Code of Nomenclature for algae, fungi, and plants (Turland et al., 2018), and hence the new names contained in the electronic version are effectively published under that Code from the electronic edition alone. In addition, new names contained in this work that have been issued with identifiers by IPNI will eventually be made available to the Global Names Index. The IPNI Life Science Identifiers (LSIDs) can be resolved and the associated information viewed through any standard web browser by appending the LSID contained in this publication to the prefix "http://ipni.org/." The online version of this work is archived and available from the following digital repositories: PeerJ, PubMed Central, and CLOCKSS.
Ecuadorian Pterichis are distributed along the Andes in three various ecoregions (Olson et al., 2001;Fig. 2) and often two or more species co-occur in the area of 25 × 25 km (Fig. 3). The highest number of genus representatives (13) was found growing in the Eastern Cordillera real montane forests ecoregion (NT0121). Northern Andean páramo (NT1006) is a home to ten Pterichis species and seven taxa occur in Northwestern Andean montane forests (NT0145).
Habitat and ecology: Terrestrial plants growing on roadsides, in cloud forest, humid montane forest and paramo at the altitudes of 2,300-3,870 m. Flowering occurs in January, April, June, and July.
Notes: This species is considered by some authors (Schweinfurth, 1941(Schweinfurth, , 1958 as conspecific with Pterichis galeata, which is easily distinguished from P. acuminata by long-clawed petals being longer than dorsal sepal (by 10-20%) and auriculate lip basal part. In somewhat similar P. meirax the petals are oblong-lanceolate, with some hairs on the margin and the lip basal part is transversely elliptic.
Habitat and ecology: Terrestrial on roadside and in secondary vegetation dominated by Freziera Willd. (Theaceae) at the altitude of 3,050-3,100 m. Flowering in Ecuador occurs in August.
Habitat and ecology: Terrestrial in elfin forest and steep slopes along road at the altitude of 3,200-3,500 m. Flowering occurs in April and May.
Notes: This species resembles Pterichis acuminata from which it differs by the petals shape (oblong-lanceolate in P. meirax) and transversely elliptic lip basal part (reniform in P. acuminata). P. meirax resembles P. habenarioides from which it differs mainly by its lip form. The lip of P. habenarioides is triangular-elliptic in outline, with subtriangular apical part, pubescent margins and interior papillae. The papillae on P. meirax lip are distributed also along the thickened apical margins below the ligulate apex. Etymology: Dedicated to Raffaella Ansaloni, the curator of Herbario Azuay.
Habitat and ecology: Terrestrial in paramo at the altitude of 4,100 m. Flowering in January.
Notes: This species resembles Pterichis diuris from which it can be distinguished by more or less lanceolate, ciliate petals (vs. glabrous, obliquely elliptic), broadly truncate lip base, presence of prominent knob-like projections on the lip margins (vs. with large glands along the margin), and larger lip middle lobe (almost as long as the lip lamina vs. constituting ca. 1/6 of the lip length). The similar, long lip middle lobe is observed in P. aragogiana, but it this species sepals are caudate and petals are linear and glabrous.
Type collection deposited in HA consists of two plant, and the holotype is plant on the left hand with mature inflorescence. Species similar to Pterichis acuminata but with sparsely ciliate sepals, prominent lip middle lobe and lip being as long as wide.
Habitat and ecology: Terrestrial in scrub and ridge-top vegetation above tree limit at the altitudes of 3,000-3,150 m. Flowering in September.
Notes: Species similar to Pterichis acuminata but with sparsely ciliate sepals (vs. sepals densely ciliate), prominent lip middle lobe constituting half of the total lip length (vs. up to 1/3 of the total lip length) and lip being as long as wide (vs. wider than long).    Distinguished from typical form of Pterichis elliptica by the epiphytic habit, by the long, oblong-elliptic lip middle lobe which constitutes more than 1/3 of the total lip length.
Habitat and ecology: Rupicolous, in grass páramo and virgin elfin forest as well as on slopes along road in cloud forest at the altitudes of 2,700-3,850 m. Flowering occurs in January, March, May, June, July, and August.
Notes: This species is similar to Pterichis triloba which, however, has oblong-elliptic to oblong-lanceolate petals widened near the middle. The 2-3-veined petals makes P. multiflora somewhat similar to P. triangularilabia and P. habenarioides but in P. multiflora petals are 5-6 times longer than wide (vs. 3-4 times longer than wide). The illustration of type specimen deposited in K was made based on plant deposited in the same herbarium, however, we did not find this specimen among herbarium sheets.
Habitat and ecology: Terrestrial in cloud forest changing into shrubby paramo at the altitudes of 2,500-2,900 m. Flowering occurs in April.
Notes: This species resembles Pterichis habenarioides in having sparsely ciliate floral bracts, glabrous sepals and sparsely ciliate petals, but it is easily distinguished from the latter by  Etymology: Dedicated to Dr. Calaway Dodson (1928Dodson ( -2020, eminent orchid taxonomist, who described numerous orchid species from Ecuador. He was the author of partial treatments of Orchidaceae for the Flora of Ecuador project of Gothenburg University (Sweden) and the Universidad Catolica of Ecuador. also the taxonomic research are in crisis (Tillier, 2000;Dubois, 2003). The lack of clear characteristic of particular species results in numerous misidentifications of known taxa and false local species checklists (Dubois, 2003). According to our findings only floral bracts and perianth segments are diagnostic characters that allow to identify Pterichis species, however, the importance of several characters requires further studies-the genetic analyses could help resolve some classification doubts. For example we found that P. acuminata is characterized by a significant variation and we are not able to clearly state that small deviations from the typical morphology of the floral segments are enough to recognize some populations as separated species (see notes in P. acuminata). The ornamentation of floral bracts seems to be consistent within the same species and the bracts are either ciliate or glabrous. Rarely intermediate form of floral bract, with just few ciliae, was observed. The similar scheme was recorded for petals and sepals which shows the same pattern of ornamentation within the species (but see notes in P. acuminata). The lip seems to be the most conservative character-its form, relative size and distribution of papillae or knobs is consistent in populations of the same species. The venation of tepals is the most disputable diagnostic character and it requires further analyses. While usually petals of Pterichis representatives are 1-or 3-veined and sepals are 3-or 5-veined, some populations with 2-or 4-veined petals were found during our research. Our new species are described based on several (at least three) differences between novelties and the most similar taxa.
In this article the new species are described based on a single or just several plants of the same collection, however, it is not an unusual situation. Preferably any new taxon should be formally named after the examination of numerous randomly collected specimens from various populations (Dubois, 2010). Nevertheless, a considerable number of species, not only plants, are described based on a single specimen (Captain et al., 2019;Wells, Johanson & Dostine, 2019). The disadvantage of using a few specimens for the description of new taxa, particularly of new species, is that the intraspecific variation cannot be evaluated. As calculated by Raven et al. (2020) an average of 749 new vascular plant species has been described annually from Latin America for the past 25 years and this rate did not decrease with time. According to some estimates (Bebber et al., 2010) about 70,000 species of flowering plants are waiting to be discovered and named. Around half of the anticipated missing species presumably have already been collected and these are deposited in herbaria awaiting identification (Bebber et al., 2010). On the other hand, Fontaine, Perrard & Bouchet (2012) calculated that an average time between the first collection of a specimen of a new species to its formal description is 21 years. Considering the ongoing habitat loss it is not therefore surprising that numerous novelties found in herbarium are difficult to locate in its natural habitat and for that reason the number of samples used in new species description is often limited. According International Plant Name Index (IPNI) only in 2019 more than 150 new Orchidaceae species were described. Novelties were found mainly in tropical in subtropical regions and numerous new names, for example Dichaea amazonica Pupulin, Epidendrum brevicallosum Hágsater & E. Santiago, were published based on single specimen. By examination of numerous Pterichis from various geographical regions (Kolanowska & Olędrzy nska, 2015;Kolanowska & Szlachetko, 2017) we were able to recognize the diagnostic characters of this genus representatives and only these taxonomically important traits were used to describe new species.
The last study which included the recognition of Pterichis diversity in Ecuador included only six species . In contrast to  concept which did not recognize P. seleniglossa as separated species, in our opinion this taxon clearly differs from all other genus representatives and can be distinguished from similar P. triloba by 1-veined petals (vs. 3-veined). In our study we did not find any population of P. triloba or P. seleniglossa with intermediate, 2-veined petals hereby in our opinion this character is sufficient for species separateness.

CONCLUSIONS
Here we presented the synopsis of Ecuadorian representatives of Pterichis. In our opinion species characteristics and identification keys will be useful for local scientists working on local floras inventories and for launching more sophisticated nature management programs.
We confirmed the occurrence of 17 Pterichis species in Ecuador. That number includes four new species described in this article. Seven genus representatives are endemic and were not so far found outside the country-P. ansaloniana, P. dodsoniana, P. elliptica, P hirtziana, P. madsenii, P. meirax, and P. tunguraguona. National Pterichis occur in just three ecoregions (Eastern Cordillera real montane forests, Northern Andean páramo, Northwestern Andean montane forests) and they are growing usually as terrestrial herbs between 2,300 and 4,110 m a.s.l.