Fioritura negli orizzonti di vegetazione della Val di Magra (Toscana)

Riassunto

Nella Val di Magra, ai confini della Toscana con la Liguria e della Toscana con l'Emilia, nei vari mesi di un triennio (anni 1988, 1989, 1990) è stata seguita la fioritura in alcune cenosi e messa in relazione ai dati della stazione meteorologica di Pontremoli, rilevati nello stesso periodo. Le piante a fioritura primaverile entrano in antesi prima ad altitudini inferiori, successivamente ad altitudini superiori (Helleborus odorus, Primula vulgaris, Erica carnea). Le piante che fioriscono nella tarda estate e in autunno entrano in antesi prima ad altutudini superiori, in seguito a quelle inferiori (Calluna vulgaris, Solidago virgpaurea, Hieracium racemosum). Sia le piante primaverili che autunnali hanno di regola un breve periodo di fioritura. Si nota una fioritura lunga in alcune piante estive (Centranthus ruber, Dianthus seguieri, Scabiosa columbaria, Geranium nodosum, Potentilla erecta).

In the Magra Valley, in the border of Tuscany district with Liguria and Emilia districts, plant flowering of some coenosys (Mediterranean bush, 50 m alt.; pinewood with Pinus maritimus, 300 m alt.; chestnut grove in oak-horn beam woods environment, 400 m alt.; chestnut wood from turkey oaks-horn beam woods derived, 700 m alt.; beech-wood, 900 m alt., bilberry heath, 1750 m alt.) was studied during several months of 3 years (1988, 1989, 1990). It was also correlated with the meteorological data of Pontremoli station of the same period. Flowering of the two Dozzano sit coenosys (pinewood and chestnut wood in oak-horn beam woods environment) was already studied in 1955 (FERRARINI, 1964), data are reported in comparison. Spring blooming species get in anthesis at first at lower altitudes and later at higher altitudes (Helleborus odorus, Primula vulgaris, Erica carnea). Late in the Summer and in the Autumn flowering plants get in anthesis at first at higher altitudes, later at lower ones (Callana vulgaris, Solidago virgaaurea, Hieractum racemosum). Both Spring and Autumn blooming plants have generally a short flowering period. A long blooming period in some Summer blooming plants is noted (Centranthus ruber, Dianthus seguieri, Scabiosa columbaria, Geranium nodosum, Po ten tilla erecta).

In the mediterranean bush flowering remains all the year with a great number of blooming plants in June; in the bilberry heath it remains from May to September with the greatest number in July; in the other vegetation horizons blooming remains from March to October pratically, with the greatest number in July, when May and June have low minima temperatures (1990); with the greatest number in May, when minima of April and May are rather high and with a rainy April (1989). Some plants, that usually start to bloom late in the Winter, increasingly earlier flowering considerably, when they are stimulated by a cold wave (Ulex europaeus, Coronilla emerus, Erica carnea).

Key words:

• flowering
• Magra Valley
• meteorological data
• northwestern Tuscany
• vegetation horizons