Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin., 2013

Fenaroli, Franco, Pistarino, Annalaura, Peruzzi, Lorenzo & Cellinese, Nico, 2013, Campanula martinii (Campanulaceae), a new species from northern Italy, Phytotaxa 111 (1), pp. 27-38 : 30-33

Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin. , sp. nov. ( Figs. 2–3 )

Planta perennis, caules prostrato-ascendentes, stolones longi radicantes et post anthesin rosulas foliorum basalium gignentes. Radices firmae, ramosae, per solum vel fissuras rupium elongatae. Caules glabri vel rarius sparsim pilosi, habitu saepe dumoso. Folia basalia longe pedunculata, lamina ovato-reniformis vel rotundata; caulina sessilia, linearia vel lanceolato-linearia, inferiora plerumque denticulata. Calix semper papillosus, nervis prominentibus; laciniae patentes vel reflexae, plerumque dimidia corolla breviores. Corolla conico-campanulata, caerulea vel sublazulina; corollae tubus basi sparsim papillosus. Ovarium papillosum; capsula papillosa, dehiscens poris basalibus. Floret junio ad octobrem, frequenter in serum autumnum. Crescit tantum in solo calcareodolomitico.

Type: — ITALY. Benaco nord-occidentale, BS, Tremosine, Valle di Bondo lungo la strada che sale al Passo di Nota, su Dolomia Principale, 23 August 2006, F. Fenaroli s.n. (holotype FI!; isotypes FLAS!, HBBS!, MRSN!, PI!; paratypes ibidem, 30 August 2009, F. Fenaroli s.n., HBBS!)

Perennial herb, (10 –)20 – 60(– 100) cm in height, prostrate-suberect stems, glabrous, rarely lightly pubescent, always with long hypogeal stolons developing a rosette of leaves in late autumn. Roots robust, 2 – 8 mm in diameter up to 10 – 12 mm when deep in the soil, branched and elongated within the substrate. Leaves forming a basal rosette, petiole (10 –)20 – 30(– 100) mm, lamina ovate-reniform to rounded, 15(– 30) × 20(– 40) mm, margins acutely dentate, mostly absent during summer anthesis, often present during fall anthesis; leaves along the stem numerous, sessile or subsessile with tapering lamina, linear-lanceolate, (1 –)2 – 3(– 5) × 30 – 60(– 100) mm, lightly dentate, the upper leaves larger than the inferior ones. Inflorescence a terminal and lateral raceme with (10 –)15 – 40(– 90) flowers supported by a robust peduncle. Calyx with prominent veins, papillose, calyx lobes (4 –)7 – 12(– 15) mm, about (1/4 –)1/3 – 1/2 the corolla length, patent or reflexed when mature, sometimes erect. Flowers pendulous but buds always erect, corolla (15 –)20 – 25(– 30) mm long, pale blue, conical-campanulate, papillose near the base, stigma trifid, style (12 –)15 – 20(– 24) mm long, usually shorter than the corolla, stamens initially fused to the style, anthers caduceus, base of the filament enlarged and ciliate along the edges, proterandry present, ovary papillose. Fruit a capsule, (3 –)4(– 5) × (4 –)5 – 6(– 7) mm, papillose, with 10 prominent ribs, pendulous when mature, dehiscence by opening of basal valves. Seeds 0.3 – 0.5 × 0.8 – 1.2 mm, elliptical, curved outwards, translucent, brown or reddish-brown in color ( Fig. 4a, b, c ). SEM images reveal that seed surface appears striate ( Fig. 5a ).

Synonyms:— C. macrorhiza sensu Auct. Fl. Brixiae , C. rotundifolia pro parte sensu Auct. Fl. Brixiae, C. bertolae sensu Auct. Fl. Brixiae , C. marchesettii sensu Martini et al. (2012) .

Phenology: —Mid-June to end of October; rarely late flowering in mid-November early-December.

Cytology: —2n = 102 chromosomes, counted on plants coming from locus classicus (Valle di Bondo, Tremosine). Since the basic chromosome number within C. rotundifolia complex is x = 17 ( Nurmi, 1987), C. martinii can be interpreted as a hexaploid species. Accordingly, the new species shares the same ploidy level as C. bertolae , as confirmed also by our counts performed on plants coming from Germagnano, Varisella and Pian Bausano (Piemonte, province of Torino). Supported by additional morphological observations, cytology suggests a closer relationship between C. martinii and C. bertolae with respect to C. marchesettii . Moreover, hexaploid cytotypes of C. rotundifolia seem to occur very far from the range of both C. bertolae and C. martinii , which therefore deserve specific status despite the lumping within C. rotundifolia of tens of Campanula taxa recently proposed by Castroviejo et al. (2010), i.e. for Italy, besides C. bertolae and C. marchesettii : C. apennina Podlech (1970: 216) , C. forsythii (Arcangeli) Podlech (1965: 81) , C. macrorhiza , C. micrantha Bertoloni (1851: 623) , C. stenocodon Boissier & Reuter (1856: 112) , C. tanfanii Podlech (1965: 95) .

Etymology:—The epithet is dedicated to Fabrizio Martini, botanist at the University of Trieste.

Habitat:— C. martinii exclusively grows on dolomitic substrates, particularly on deeply weathered rocky ravines, along roads on rocky walls but with soil structure that allows deep rooting. The morphological variability is strictly correlated with the habitat where this species occurs. C. martinii has typically a robust habit, with plants up to 90 cm tall, densely branched, with decumbent stems and 30 – 90 flowers. However, in open pine communities on rich soils - for instance in Valle di Bondo, under Pinus sylvestris Linnaeus (1753: 1000) at 500 – 1200 m and under Pinus mugo Turra (1764: 152) at 1200 – 1600 m - the plants are smaller, up to 50 cm tall, and with 10 – 30 flowers.

Distribution range:— C. martinii is currently known to occur on dolomitic rocks known as "Dolomia Principale". This type of substrate is widespread in the Prealps of Brescia, Bergamo, and Lecco to the provinces of Como and Varese ( Fig. 1 ). Additionally, C. martinii is found also on limestones (known as “Formazione della Corna”, for example as on Mt. Maddalena), although this species prefers calcium carbonate substrates that are rich in magnesium. Conversely, C. bertolae is a species typical of altered serpentine rocks rich in phyllosilicates made up predominantly by iron and magnesium, a substrate characteristic of the western Alps, northern Apennine and southern Italy ( Dal Piaz, 1971, Compagnoni et al., 1983). C. rotundifolia shows no preference concerning the geological substrate. In the Prealps of Brescia, this species generally occurs in acidic soils, even when deriving from limestone rocks.

Taxonomic relationships:— C. rotundifolia shows always glabrous ovaries: Pignatti (1982) described the latter species as having either glabrous or papillose ovaries just because of confusion with C. martinii , which is always marked by dense papillae. C. bertolae shows papillae on the ovaries only sporadically. The comparison of morphological features among the three morphologically close species is summarized in Table 1. The differences of seeds and capsules morphology between C. martinii e C. bertolae are shown in Figures 4 and 5 . Other related species are easily distinguishable from C. martinii . For example, C. macrorhiza has a lignified rhizome covered with remains of dead leaves, patent flower peduncles and appressed or reflexed calyx teeth; C. carnica has a scandent stem 10–40 cm high and calyx teeth that are as long as least half the length of the corolla; C. marchesettii has a stem up to 60 cm in height, inflorescences with reduced number of flowers and appressed calyx teeth; C. witasekiana has pendulous flowers with capillary peduncles, and fusiform root tubercles; finally, C. micrantha has a thin rhizome, axillary racemes, flowers with a small corolla (10–12 mm) and capillary peduncles.

Figures

FIGURE 1. Known distribution of Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin. (modified from Marazzi 2005).

FIGURE 2. Holotype of Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin. (FI).

FIGURE 3. Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin. (Photo F. Fenaroli).

FIGURE 4. Capsules and seeds of Campanula martinii F.Fen., A.Pistarino, Peruzzi & Cellin. (a, b, c) and Campanula bertolae Colla; bars = 1 mm. No formal comparison was made with C. rotundifolia because capsules are consistently glabrous.

FIGURE 5. SEM images of C. martinii (a) and C. bertolae (b) seed surfaces (x 1500).