& Pyrus pedrottiana ( Rosaceae ), a new species from the Nebrodi Mountains (N-E Sicily)

Raimondo, F. M., Venturella, G. & Domina, G.: Pyrus pedrottiana ( Rosaceae ), a new species from the Nebrodi Mountains (N-E Sicily). — Fl. Medit. 32: 25-34. 2022. — ISSN: 1120-4052 printed, 2240-4538 online. A new species of Pyrus for the dendroflora of Sicily is here described. It is Pyrus pedrottiana , actually considered endemic to the Nebrodi Mountains, a territory which includes the largest wooded area of the island with a high forest biodiversity.In the same area, P. vallis-demonis and P. ciancioi have also been described in recent times. The authors report diagnostic characters to distinguish the new taxon from the other two sympatric species.


Introduction
In Italy, Pyrus L. is represented by 10 species (Bartolucci & al. 2018;Arrigoni 2018;Pignatti 2019). The number of species, if compared with the first edition of Flora d'Italia (Pignatti 1982), has significantly increased in recent decades, thanks to the descriptions of five new taxa, four of which from Sicily (Marino & al. 2013). In Sicily, recent scientific papers have led to the description of Pyrus castribonensis Raimondo, Schicchi & Mazzola, P. sicanorum Raimondo Schicchi & P. Marino, P. vallis-demonis Raimondo & Schicchi, and P. ciancioi P. Marino, G. Castellano, Raimondo & Spadaro, the last two described from the Nebrodi Mountains. The exploration of the Nebrodi territory-not well explored in the past and particularly rich in taxa that are difficult to classify,-allowed the identification of new species, both woody and herbaceous. Periodic observations carried out in a large population of Pyrus, allowed to separate and describe a new species, probably endemic to the Nebrodi. Compared to the other Pyrus species already described, it has an even more significant forest value, both for its dendrological characteristics and for its widespread presence in the Quercus cerris woods on the northern side of the vast mountain system of eastern Sicily. In this area, the new taxon -described with the name of Pyrus pedrottiana -comes into contact only marginally with P. vallis-demonis, from which, however, it differs considerably, while it remains sufficiently isolated with respect to P. ciancioi, a species which is also morphologically well characterized.

Materials and method
After noticing the presence in the wild of a population not corresponding to the taxa already known in Sicily, phenological observations in the field were carried out for a threeyear period on 20 very similar plants. These plants were randomly selected within an area of ca. 10 hectares in which the population studied assumes greater quantitative impact as well as a constant unmistakable connotation. The observations, carried out for comparison, also concerned other plants of the same genus present in a discontinuous and fragmentary way in the same area, north-east of Lake Maulazzo, straddling the municipalities of Militello Rosmarino and Alcara Li Fusi, at ca.1400 m. The study was completed through comparisons with herbarium materials, with particular reference to the species recurrent in the whole Sicily [P. pyrainus Raf., P. pyraster (L.) Duroi, P. spinosa Forssk.] and in the Nebrodi Mountains (P. vallis-demonis and P. ciancioi) and in the nearby Madonie Mts (P. castribonensis). Our study was completed by chorological observations throughout the Nebrodi territory in order to circumscribe the area occupied by the critical taxon.

Pyrus pedrottiana
Etymology -The epithet of the name of the new species recalls the surname of the illustrious active naturalist and plant ecologist Franco Pedrotti, professor emeritus of Botany at the University of Camerino (Italy), in the occasion of his 88 th birthday.
Phenology -The species flowers in May along with leaf emission (Fig. 2) fruits ripen in October. The ripening of the fruits and the fall of the leaves occurs 2-3 weeks earlier than the other species of Pyrus occurring in the same area.
Distribution and ecology -Mesophilous species, well represented in the area of the Nebrodi Mountains where it occupies the humid, north slopes. The distribution area covers the submontane belt characterized by extensive forests of Quercus cerris L. and occupies the potential space of the associations of the order Quercetalia-pubescentipetraea, between 1300 and 1500 m; in particular it occurs in the area around the locus classicus (Fig. 4). In this context, it widely colonizes clearings, exploiting the radical polloniferous capacities. It is no coincidence that some groups of individuals of this species are managed, from the silvicultural point of view, following the same treatment reserved for Turkey oak (Fig. 3f). The presence of Quercus cerris to which they are associated include also: Crataegus monogyna L., C. Characters of the population -The population of the species occurs in an area of about 1000 hectares inside the Regional Park of Nebrodi. Within this area, however, the species occurs in dense and extensive groups of plants of various ages and development (Fig. 3).
Overall, it is estimated the number of mature individuals exceeds 5 thousand units.

e f
Taxonomic relationships -On the basis of the taxonomic arrangement of the genus Pyrus by Terpò & Amaral Franco (1968) and according to the actual systematic and taxonomic conceptions of the genus in relation to the European flora (Terpò 1984;Browicz 1993;Aldasoro & al. 1996;Aedo & Aldasoro 1997), Pyrus pedrottiana is to be included within the group characterized by pomes with caduche calyx that includes also P. vallisdemonis and P. castribonensis in Sicily, and P. cordata in Italy. Pyrus pedrottiana has some morphological affinities with Pyrus pyraster, however, compared to this very variable taxon, it is well distinguished by the persistent calyx as well as in P. communis and P. spinosa. The same with respect to the two other endemic taxa described in the same area of the Nebrodi Mts, such as P. vallis-demonis and P. ciancioi (Fig.5). From the former, P. pedrottiana is distinguished by the exceptionally pear-shaped fruits (with shorter peduncles (Fig. 1e), as well as by the different morphology, color and leaf consistency, not dark and rigid as in P. vallis-demonis . The character of the crown is also different: rising, with a tendency to pyramidal shape ( Fig. 3a, b, e). Compared to P. ciancioi, the new taxon not only stands out for its leaf morphology and absence of tomentosity, but also for the shape and size of the fruit and peduncles, which are much shorter and stockier than in P. ciancioi, Furthermore, differences with the two taxa of the Nebrodi are observed in the flowers: in particular, in the sepals of the P. pedrottiana there is a thin marginal indentation and the mucronate, ferruginous apex, curved on the outside (Fig. 1e): this character is absent in all the other species of Sicily. P.ciancioi, then, is well distinguished from P. pedrottiana for the pommel regularly and not exceptionally with a persistent calyx.