Campanula bergomensis F. Mangili & L. Mangili, 2024

Valle, Barbara, Eustacchio, Elena, Gallo, Guido Roberto, Beretta, Mario, Bonelli, Marco, Zanzottera, Alice, Gianfranceschi, Luca, Federici, Germano, Mangili, Federico, Mangili, Luca, Perico, Giovanni, Traini, Myriam & Caccianiga, Marco, 2024, Campanula bergomensis (Campanulaceae), a new species from Bergamo Prealps (Northern Italy), Phytotaxa 637 (2), pp. 120-132 : 124-130

Campanula bergomensis F. Mangili & L. Mangili sp. nov. ( Figs. 3–8 )

Description: —Perennial herb, (4–) 10–20 (–30) cm tall, with ascending-erect, glabrous or sparsely hairy, squarecross-section stems, with strong, horizontal creeping rhizomes from which a rosette of leaves develops ( Fig. 3A– C ; Fig. 4 ). Roots robust, branched and elongated underground. Basal leaves forming rosettes, with 10–20 mm long petioles, lamina oval-rhomboid 9–12 x 6–7 mm, glabrous, margin weakly toothed, sometimes sparsely hairy, often witheread during summer anthesis ( Fig. 3A–D ; Fig. 4 ); stem leaves numerous, sessile, linear-lanceolate, acute, (7–) 15–21 (–30) mm, glabrous, margin entire, on lower portion of stem close together, then spaced and decreasing upwards ( Fig. 3A , Fig. 4 ). Inflorescence a raceme with 2–4 flowers, supported by long peduncles ( Fig. 3A ; Fig. 4 ). Calyx glabrous, with laciniae 2–3 mm slightly larger than the tube and appressed to the corolla ( Fig. 3E , Fig. 4 ). Buds and flowers pendulous; corolla (9–) 11–12 (–14) mm, hemispherical-campanulate, not constricted in upper part, light blue ( Fig. 3E–F , Fig. 4 ); trifid stigma not protruding. Fresh pollen color whitish, becoming yellow when drying out; mature pollen grains suboblate (P/E= 0.87), released as free monads of medium size (30 μm); grains radially symmetric, isopolar, triporate and zonoporate ( Fig. 5 ); tectum discontinuous with muri (thickness around 0.20 μm) and lumina; spinulae present, shorter than 3 μm; sometimes granules present; ornamentation rugulate-microreticulate and echinate ( Fig. 5 ). Capsule pendulous, ovoid, dehiscent. Seeds about 0.9 mm long ( Fig. 3G ; Fig. 4 ).

Type: — ITALY, Val Borlezza BG, Clusone , Ponte della Selva, Val Cabrosna, sentiero di fondovalle, 625 m, ghiaione ricco di calcare, 15.VIII.2007, Leg. Perico, 18 Apr. 2023 (holotype BER!; isotypes in BER!; paratypes ibidem 15.VIII.2007, leg. Perico), ( Fig. 6 ) .

Synonyms:— Campanula cespitosa sensu Martini et al. (2012) , non Scop., Fl. Carniol., ed. 2, 1: 143 (1771); Campanula rotundifolia pro parte sensu auct. fl. bergomensis, non L., Sp. Pl.: 163 (1753).

Phenology:—Flowering from mid-July to mid-August.

Habitat and ecology:— Campanula bergomensis grows on dolomitic debris cones, ledges of rough grassland, generally on poorly developed and well-drained soils ( Fig. 3B ). Its elevational distribution ranges from 450 to 1,250 m a.s.l. The area of occurrence is characterized by an annual average temperature of 11 ° C in Clusone (data from Ufficio Idrografico del Po, 1958–1982°) and rainy climate (1500 ml/y in Clusone; Ceriani & Carelli, 1990). The species is particularly associated with wide and flat debris cones, an unusual geomorphological feature in the Lombardian Prealps. C. bergomensis can be found on the edge of Pinus mugo Turra vegetation (with Amelanchier ovalis Medik. , Sesleria coerulea ( L.) Ard., Calamagrostis varia (Schrad.) Host , Hieracium sp. , Dryas octopetala L., Globularia cordifolia L.), where the slopes are sparsely vegetated. C. bergomensis shows a S-R strategy (leaf traits and CSR graph are reported in supplementary material in Table S 2 and Fig. S1 , respectively).

Distribution range: — Campanula bergomensis occurs in a few areas of the Orobic Prealps, within the borders of Bergamo Province (Lombardy, Italy). ( Fig. 1 , 7 ).

Etymology:—The epithet refers to the Province of Bergamo (called “Bergomum” in Roman antiquity), where all known populations of the new species are found.

Taxonomic remarks:— Morphological and genetic evidence support Campanula bergomensis as a species new to science. In particular, it is morphologically distinguished from C. cespitosa for having 1) the racemose inflorescence with less flowers compared to C. cespitosa (2–3 and 6, on average, respectively; Fig. 8 and Fig. S2 ); 2) the shape of the corolla (not constricted at the apex, like in C. cespitosa ); and 3) the whitish-yellow pollen surface with many spinulae, instead of pink and with few spinulae like in C. cespitosa ( Fig. 8 ). Genetically, C. bergomensis is well-distinguished from, though close to both C. cespitosa and C. cochleariifolia ( Fig. 2 ), which have been consistently recovered as sister species ( Mansion et al. 2012; Crowl et al. 2014, 2016). Although morphology would suggest that C. bergomensis is closer to C. cespitosa than to C. cochleariifolia , which is macroscopically very different, our genetic data are not so clear in confirming the phylogenetic relationships among these three closely related species and further investigations are needed, possibly including the comparison of more genes.

Figures

FIGURE 1. Distribution of Campanula bergomensis (blu squares) and C. cespitosa (green and red squares). Red squares indicate the grids where C. cespitosa samples for genetic analysis were collected. Cartographic grid is taken from Ehrendorfer and Hamann (1965). Bibliographic data of C. cespitosa are: Andreatta et al. 2020 (Veneto, Italy), Martini et al. 2023 (Friuli-Venezia Giulia, Italy), Wilhalm et al. 2014 (Alto Adige, Italy), Jogan et al. 2001 (Slovenia), Hartl et al. 1992 and Staudinger et al. 2009 (Austria).

FIGURE 2. ML phylogenetic reconstruction of relevant Campanula species. Species selection is explained in the methods section. Bootstrap values are shown on each node. Jasione montana is selected as the outgroup.

FIGURE 3. Morphological features of C. bergomensis A: plant habitus (scale bar 5 cm). B: the plant in its habitat. C: winter habitus. D: leaf shapes (scale bar 1 cm). E, F: flower shape and fresh pollen color (scale bars 1 cm). G: seeds on millimetre paper to show shape and size.

FIGURE 4. Illustration of C. bergomensis (bars subdivisions 5 mm). “le”= leaf, “pl”=plant, “fl”=flower, “st”=stamen”, “sy”= style”, “sg”= stigma, “se”=seeds”.

FIGURE 5. Pollen morphology of C. bergomensis. A–D: LM micrographs; E–H: SEM micrographs. A: Pollen grains as free monads showing the pores and the echinate ornamentation (scale bar = 30 µm). B: Pollen grain in polar view, the focal plane is on the echinate pole (scale bar = 10 µm). C: Pollen grain in polar view, the focal plane is on the equator showing the equatorial position of the pores (scale bar = 10 µm). D: Pollen grain in equatorial view, showing the suboblate shape (scale bar = 10 µm). E: Pollen grains as free monads showing echinate ornamentation (scale bar = 30 µm). F: Pollen grain showing the rugulate-microreticulate and echinate ornamentation (scale bar = 10 µm). G: The rugulate-microreticulate ornamentation stops near the pore margin (scale bar = 2 µm). H: The echinate ornamentation coexists with a rugulate-microreticulate pattern (scale bar = 2 µm).

FIGURE 6. Holotype of C. bergomensis sp. nov.

FIGURE 7. Distribution of Campanula bergomensis.

FIGURE 8. Morphological comparison between C. bergomensis sp. nov. (A, C, E, G) and C. cespitosa (B, D, F, H). A, B: plants habitus (scale bars 5 cm). C, D: flower shape. E, F: dried pollen color. G, H: pollen ornamentation observed with SEM (scale bars 5 µm).