Typification of the name Potentilla asturica (Rosaceae)

. Potentilla asturica , an Iberian endemic species included within sect. Recta , is typified.


Introduction
Potentilla L. (Rosaceae) is a genus comprising about 400 species of herbaceous perennials from the Northern Hemisphere (Persoon et al., 2020). This taxonomically difficult genus includes diploid and polyploid species (Kurtto et al., 2004), with ploidy levels of up to hexadecaploid (Kalkman, 2004). Polyploidization as well as interspecific hybridization have played an important role in the evolution of Potentilla (Potter et al., 2007;Dobeš & Paule, 2010;Paule et al., 2011). In the Iberian Peninsula and the Balearic Islands 30 species were reported, of which three were endemic (Guillén & Rico, 1998).
Potentilla asturica Rothm., a member of Potentilla L. sect. Recta (Th. Wolf) Juzepchuck, is a diploid endemic to mountain areas in northwestern Spain and northern Portugal (Guillén & Rico, 1998;Delgado & Rico, 2000;Rico et al., 2003;Pino Pérez et al., 2011). Although this taxon has sometimes been recognized at the subspecies level [P. recta subsp. asturica (Rothm.) M. Laínz; P. hirta subsp. asturica (Rothm.) Soják] it is currently accepted at the taxonomic rank which was initially described (Delgado & Rico, 2000;Rico et al., 2003;Kurtto, 2009;Pino Pérez et al., 2011). A thorough literature survey and subsequent analysis of herbarium data on the genus Potentilla in the Iberian Peninsula, led to the realization that the name P. asturica needs to be lectotypified because Rothmaler (1935) mentioned several syntypes in the protologue. The aim of this paper is the designation of a type for P. asturica, on the basis of consultation of Rothmaler's original material cited in the protologue.

Material and methods
The present study was carried out through analysis and examination of specimens kept at BC and digital images from JE, MA and MPU [herbaria acronyms follow Thiers (2020, continuously updated)] using the relevant literature (Rothmaler, 1935;Guillén & Rico, 1998). To select type specimen, the protologue was compared with the original material, and the most complete and informative specimen was selected according to the Art. 9.3 of the Shenzhen Code (Turland et al., 2018).
After consultation of several collections, original material was located at JE and BC, including several candidates for typification of P. asturica. Four specimens correspond to the current concept of the species (Guillén & Rico, 1998). In the JE herbarium, where part of the W. Rothmaler herbarium is deposited (Stafleu & Cowan, SHORT NOTES 1983) three herbarium sheets of P. asturica exist, the first of which includes a label with information about location and date of collection: "Prov. León, El Bierzo, Sonnige Matten am Füsse der Kalkfesen "los Apostoles" an der Guiana, 1500 m alt., 10 julii 1933, W. Rothmaler, Iter Hispanicum 1933 nº. 736, (JE00001600) [http://131.130.131.10/ h e r b a r i a / j a c q -v i e w e r / v i e w e r . h t m l ? r f t _ id=je_00001600&identifiers=je_00001600] Two further sheets belonging to the original material of P. asturica are kept at JE, but they do not include indication of location or date of collection. However, these materials were apparently collected by W. Rothmaler (according to what appears on the printed label) and were numbered "Iter Hispanicum 524", which indicate that they were collected in Peñas de Ferradillo (JE00001598 and JE00001599, sub "P. hirta L. ssp. None of these sheets kept at JE bear any annotation by W. Rothmaler about its type nature, nor they were labeled as Potentilla asturica. The specimen JE00001600 was identified as "Potentilla angustifolia Ser.", whereas the sheets JE00001598 and JE00001599 were labeled as "Potentilla hirta L. ssp. P. gallaecica Rothm. n. ssp." [characteristic handwriting by W. Rothmaler]. A good candidate for typification of P. asturica is the specimen BC19703, which was collected in Sierra Segundera (Zamora province) by J. Cuatrecasas in 18 July 1928. This sheet includes a revision label "Potentilla asturicae Rothm. Det. W. Rothm. 1934 III/15" [characteristic handwriting by W. Rothmaler].
The specimens JE00001598 and JE00001599 are not in optimal condition (some leaves are considerably damaged) and they are not complete (basal leaves, anthers and fruits are missing or hardly noticeable), whilst sheets JE00001600 and BC19703 are complete and well preserved, although the latter is found in better condition, with the most important diagnostic characters of the species well visible. As this specimen bears a label handwritten by W. Rothmaler with the name Potentilla asturica [as "P. asturicae"], it is evidently the best option for designation of a lectotype. This label provides strong evidence that the author used this specimen to describe the species. Rothmaler, at the time of the description of P. asturica, was established in Spain, and was professionally linked to the Botanical Institute of Barcelona (see Font Quer, 1962). Therefore, the specimen BC19703 is chosen and designated here as the lectotype of the name P. asturica:

Taxonomic remarks
Potentilla asturica was previously subordinated as a subspecies within P. recta (Laínz, 1964) and P. hirta (Soják, 1993). In fact, the first scientific name to designate this plant was published at subvarietal level within P. hirta by Merino (1912), who described it from plants collected in Galicia, Orense province ["montes de Ramilo en el paraje llamado Choza"]. However, a multivariate morphometric study of the Iberian representatives of sect. Recta (Rico et al., 2003) supported the recognition of P. asturica as a separate species, being more closely related to P. hirta, with which it shares the same chromosome number, 2n=14 (Delgado & Rico, 2000) than to P. recta. As indicated by Rico et al. (2003), P. asturica is the less morphologically variable Iberian species included within sect. Recta. After our revision of herbarium material of the Iberian taxa included within sect. Recta, we agree with the taxonomic proposal of Guillén & Rico (1988) and Rico et al. (2003), and also with the appreciation of the scarce morphological variability of P. asturica. However, the study of the herbarium material has revealed a diagnostic character of this species shows some variability with respect to that established by Guillén & Rico (1998) and Rico et al. (2003). According to the aforementioned works, P. asturica has entire stipules, but we have observed a specimen of P. asturica with incisedtoothed stipules in the middle cauline leaves. It is remarkable that the denticulation of the stipules is diagnostic character in sect. Recta and it was used in the dichotomous key of the species by Guillén & Rico (1998). Specifically, a specimen collected in Monte de la Regaliza, supra Leitariegos, 1750 m (BC86939) has the stipules incised of middle cauline leaf (this is appreciable in the longest stem in this sheet). This unusual character in P. asturica was found in a specimen of remarkable development for what is usual in this species, to the extent that Rothmaler identified this specimen as "P. asturica var. robusta n. var.", a name that, as far as we know, never has been published. Since no other studied specimen of P. asturica (not only in BC, but also in digital images of JE) has incised stipules, this apparently should rarely occur in this species.