Chromosome numbers for the Italian flora: 9

In this contribution, new chromosome data obtained on material collected in Italy are presented. It includes counts from six populations of three taxa within the genus Pulmonaria, two of which are endemic to Italy (P. vallarsae subsp. apennina and P. vallarsae subsp. vallarsae); the other is the widespread European P. officinalis. In addition, two counts from Potentilla detommasii and Stachys thirkei, two eastern Mediterranean species, are also reported.

among plants showing 2n = 22 chromosomes at Passo del Muraglione. However, in the present study, we found there only plants with 2n = 22 chromosomes (12 individuals studied). In both cases, we highlight the rarity of chromosome numbers different from 2n = 22, which is typical of P. vallarsae subsp. apennina, although a population showing 2n = 26 chromosomes has been recently recorded from Abruzzo  Method. Squash preparations were made on root tips obtained from potted plants. Root tips were pre-treated with 0.4% colchicine for 3 hours and then fixed in Carnoy fixative solution for 1 hour. After hydrolysis in HCl 1N at 60 °C, the tips were stained in leuco-basic fuchsine.
Observations. Pulmonaria vallarsae subsp. vallarsae is endemic to Trentino-Alto Adige and Veneto (Cecchi and Selvi 2015), and it was described by Kerner (1878) on plants occurring in Vallarsa, the valley of the river Leno situated southeast of Rovereto, which is the locus classicus for this species (Puppi and Cristofolini 1996). Pian delle Fugazze, the northern summit of the valley, is among the localities cited in the protologue.   Method. Squash preparations were made on root tips obtained from potted plants. Root tips were pre-treated with 0.4% colchicine for 3 hours and then fixed in Carnoy fixative solution for 1 hour. After hydrolysis in HCl 1N at 60 °C, the tips were stained in leuco-basic fuchsine.
Observations. These plants display intermediate morphological features between the typical P. hirta and the typical P. vallarsae subsp. apennina (Puppi and Cristofolini 1996;Cecchi and Selvi 2015), although showing a closer resemblance to the former species, whose range spreads from SE France to C Italy (Cecchi and Selvi 2015). Four out of six samples in this population were found to have 2n = 28 chromosomes, which is typical for P. hirta Pupillo et al. 2019), whereas the remaining two individuals were found to have 2n = 22 chromosomes. Plants with 2n = 22 and 28 chromosomes grow together and do not show any pattern relating chromosome number to a specific morphological syndrome, as already observed by Vosa and Pistolesi (2004) for other populations.  Observations. Plants in this population show some morphological features that are intermediate between P. officinalis and P. vallarsae, especially in terms of leaf shape and maculation. However, the cordate leaf base and the presence of aculeoli (very short conical hairs) clearly place these plants within P. officinalis subsp. officinalis (Bolliger 1982), a taxon that is widespread in Europe. This is also confirmed by the chromosome number 2n = 16, found in all nine individuals studied, which is typical of P. officinalis (Sauer 1975;Bolliger 1982). Because of the faint maculation of most of the plants, these plants resemble P. officinalis subsp. marzolae G.Astuti, Peruzzi, Cristof. & P.Pupillo, known so far for Trentino-Alto Adige only. However, the presence of aculeoli in the population studied here does not match with their absence in P. officinalis subsp. marzolae (Astuti et al. 2014). Therefore, these plants could be safely ascribed to a faintly spotted form of P. officinalis.
L Method. Squash preparations were made on root tips obtained from germinating seeds. Root tips were pre-treated with 0.4% colchicine for 3 hours and then fixed in Carnoy fixative solution for 1 hour. After hydrolysis in HCl 1N at 60 °C, the tips were stained in leuco-basic fuchsine.
Observations. This species spreads from peninsular Italy to Turkey, but it is not recorded for Croatia and Montenegro (Kurtto 2009). Here we report the first chromosome count for P. detommasii from Italy, which agrees with the only other count available for this species (Markowa 1971), confirming its diploid status.
G. Astuti, L. Peruzzi Method. Squash preparations were made on root tips obtained from cultivated plants. Root tips were pre-treated with 0.4% colchicine for 4 h and then fixed in Carnoy solution for 1 h. After hydrolysis in 1N HCl at 60 °C, the tips were stained with leuco-basic fuchsine.
Observations. This species grows in the eastern Mediterranean, showing a main distribution range in the Balkans, but extending eastwards to Turkey and westwards to Italy (Ball 1972). This species has been recorded for Marche (Bartolucci et al. 2019), where it has been found in only two localities. The specimen investigated here comes from one of these localities, and our count agrees with a previous report for Italy (Falciani and Fiorini 1996). This chromosome number is also typical of all the species belonging to Salvia sect. Eriostomum (Hoffmans. & Link) Dumort. (Falciani 1997).
G. Astuti, M. Tiburtini for their help in collecting root tips of Stachys thirkei. The authors gratefully acknowledge the financial support of "Progetto di Ricerca di Ateneo" (PRA) of the University of Pisa, grant number PRA_2018_15, for the chromosome counts of Pulmonaria.