Study reports chromosome number of 18 for seven Armeria species in Italy

A botanical chromosome-count study found a somatic chromosome number of 2n = 18 in all examined populations of seven Armeria species from Italy. The research included the first reported chromosome counts for Armeria aspromontana, Armeria garganica and Armeria macropoda.

The study was a descriptive cytological investigation of plants in the genus Armeria, within the family Plumbaginaceae. It examined voucher-backed material collected from localities in Calabria, Apulia, Abruzzo, Basilicata, Sicily and Campania. The findings concern chromosome counts for the sampled taxa and populations; they do not establish broader genetic relationships or explain the biological significance of the shared count.

For all seven taxa, investigators prepared squash preparations from root tips obtained from germinating seeds. Root tips were pre-treated with 0.4% colchicine for three hours and then fixed in Carnoy solution for one hour. After hydrolysis in 1N hydrochloric acid at 60 °C for 7.5 minutes, the preparations were stained with leuco-basic fuchsine.

Armeria aspromontana, represented by material from Contrada Nardello in the Aspromonte Massif of Calabria, had 2n = 18. The authors described this as the first chromosome-number report for the species and noted that the count matched those observed in other Armeria taxa reviewed by Rice and colleagues in 2015 and by Peruzzi and Bedini in 2024. Its endemic distribution in the Aspromonte Massif was also noted in the study.

Armeria brutia from Silvana Mansio near Monte Scuro in Calabria also had 2n = 18. The new count was consistent with an earlier count reported by Brullo and colleagues in 1995 under the name Armeria canescens. The paper described A. brutia as endemic to the Sila Massif and identified the studied material with a voucher specimen collected in June 2019.

Armeria garganica from San Marco in Lamis on the Gargano in Apulia had 2n = 18. According to the paper, this was the first chromosome-number report for the species, and it was consistent with counts recorded for other Armeria taxa. The study also described A. garganica as endemic to Apulia in southern Italy.

Armeria gracilis had 2n = 18 in six examined populations: Monte Morrone, Monte Cucco, Vado di Corno, Blockhaus mountain on the Majella, Monti della Meta in Alfedena and Serra del Prete in the Pollino Massif. The counts from Vado di Corno and the Pollino Massif agreed with earlier reports by Kovanda in 1983 and Brullo and colleagues in 1995, respectively, both published under the name Armeria majellensis.

The authors said that the sampled A. gracilis populations had been assigned to either A. gracilis subsp. gracilis or A. gracilis subsp. majellensis, but they noted that the distinction between those taxa was doubtful and required further study. They also reported that plants from the Pollino Massif had several morphological differences and required further study. The chromosome data presented here did not resolve those taxonomic questions.

Three additional species also had 2n = 18. Armeria gussonei from Rocca Busambra in Sicily matched a count previously made for the same area by Colombo and colleagues in 1980. Armeria nebrodensis from Monte San Salvatore in the Madonie matched a count from the same area by Bartolo and colleagues in 1981. Armeria macropoda was examined at Monte Terminio in Campania and Mount Serranetta near Pignola in Basilicata; its chromosome number was reported for the first time. The authors noted that the Basilicata population showed several morphological differences and resembled A. garganica more closely than the Monte Terminio material.

Overall, the study provides voucher-supported chromosome counts for seven sampled Armeria species, including three species for which the authors considered the count a first report. The results document a uniform observed count of 2n = 18 across the examined material, while the accompanying observations leave some taxonomic and morphological questions unresolved.

Subject of Research: Chromosome counts of seven Armeria species collected in Italy

Article Title: Chromosome numbers for the Italian flora: 15

Article References: Tiburtini, M., Fruzzetti, S., Baluganti, L., Conti, V., Cardella, V., Peruzzi, L., Bartolucci, F., Conti, F., Bernardo, L., Iamonico, D., Barone, G., & Giacò, A. (2024). Chromosome numbers for the Italian flora: 15. Italian Botanist, 18, 167-177. https://doi.org/10.3897/italianbotanist.18.142663

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.18.142663

Keywords: Armeria, chromosome number, Italy, cytology, Plumbaginaceae, chromosome count, botanical taxonomy, root-tip squashes, Italian flora, Chromosome, numbers, Italian