Chestnut (Castanea sativa)
In Europe, the genus is represented only by the species Castanea sativa Miller. Arboreal species native to southern Europe, North Africa and western Asia, with conical-pyramidal top in the young specimens, with tendency to become expanded, globular and irregular in the adult specimens. It can reach a height of 25 metres. The leaves are deciduous, with serrated margin and pointed apex, of an intense green colour and glossy, paler in the lower part. The Chestnut tree is a monoecious plant; the masculine inflorescences are represented by 10-20 cm long, yellow-green, spikes; the feminine ones are formed by single flowers or united in groups of 2-3 places at the base of the masculine inflorescences. The blooming takes place in full summer. The fruit is represented by a walnut called chestnut, entirely covered with a spiny dome, called hedgehog.
In the Vesuvius National Park the chestnut groves are mainly located on Mount Somma at altitudes between 250 and 1100 meters, its high spread is due to the intervention of man who preferred it for its usefulness over other species. The oldest use of the chestnut tree is for food. Chestnuts are rich in starch and in many mountain areas of Italy have represented, until the ’50s, the main source of food (chestnut flour). Semi-hard wood is used above all in the manufacture of furniture and support poles.
Asplenio (Asplenium trichomanes subsp. Quadrivalens)
The Asplenio, also known as false scalp, is a perennial rhizomatous fern belonging to the family of Aspleniaceae, typical of rocky and stony environments, capable of living in the cracks of the rock, but also in forests and shady cliffs up to over 2000 m. It has an Eurasian-suboceanic distribution which has now become almost cosmopolitan (North America, Australia), common in all regions of Italy with several subspecies.
The height of the plant does not exceed the 50 cm, usually it is, as an average, 40 cm or smaller. It takes about 5-10 years for the plant to reach its maximum development. The leaves are 4-20 cm long, simply pinnate, dark green, with linear outline, with obovate or elliptic pinnulae (leaflets), opposite, sessile, coplanar to the rachis; petioles entirely brown-blackish and glossy; in the lower page of the leaves are present thick sori. The sori are small, linear at the end, confluent. They contain ellipsoid spores (29-43 µm), with sporification from July to August.
In the Vesuvius National Park it is common in the undergrowth of holm-oaks and mixed woods on the mountainside, but also in pine forests of human origin and in rocky environments.
Neapolitan alder (Alnus cordata)
The Neapolitan alder is a tree species endemic to southern Italy, from Campania to Calabria, also present in Corsica and the Island of Elba; frequent in the Campania Apennines and on the Sila. It is a medium-sized tree that can reach 15-20 m in height with a foliage not very expanded. Mature greyish bark, young branches with brown bark with whitish patina. The leaves are simple and alternate, heart-shaped with indented edges and yellowish hairs on the bottom page. It is often associated with other broad-leaved trees (from the oak to the beech), or forms riparian forests together with the black alder (Alnus glutinosa). It is a monoecious species, with unisexual inflorescences carried on the same plant, the masculine ones formed by catkins of 7-10 cm, united in groups of 3-6, hanging to favour the pollination by the wind (anemophilous); the feminine ones are short 1-2 cm, of ovoid shape and of reddish colour, when ripe with persistent woody scales, recall in the appearance a small conifer cone. Flowering takes place at the end of winter, from February to April. The fruits are contained in strobles, first green, then dark brown grey, woody and when they open, they release small winged achenes of about 3 mm.
In the Vesuvius National Park it is associated with other species in chestnut woods, while woods at Alnus cordata have a punctiform distribution and localized on the high slopes of the mountain sum exposed to the north, where it can find coverage values of even 75%, in these contexts it develops preferably on coarse and landslide stony soils, where it has good attitudes to the consolidation of unstable slopes. It is present with individuals scattered in the pine forests of the southern slopes, indicating an evolution of the latter towards degrees of greater naturalness.
Black hornbeam (Ostrya carpinifolia)
Deciduous arboreal species of high altitude forests, up to 15 meters high with straight trunk and foliage collected and a little elongated; grows in association in woods and woods of deciduous broad-leaved trees, especially oak and Turkey oak, in an area limited to south-eastern Europe. In Italy it is present in the central-eastern pre-alpine area and in the peninsular area (from the northern Apennines to Calabria), with sporadic presences in the larger islands and on the island of Elba.
It has deciduous leaves, alternate, oval in shape, elongated and with a serrated edge; the main vein is very evident (nibs). The male inflorescences (catkins) are long and pendulous up to 10 cm, to facilitate anemophilous pollination, the female ones (ears) are shorter. It blooms in April-May, before the plant puts the leaves; each female flower is wrapped in a sort of light sack (bract), which wraps around the fruit, facilitates the flight and protects the seed during the early stages of germination. The fruits are white/green cluster achenes.
A pioneer plant, capable of growing even on shallow, stony soils, it is suitable for consolidating barren areas. In the Vesuvius National Park, it forms mixed cenotic plants of reduced extension, with coverage values not much higher than those of the other tree species making up the association; they are mainly located on the north-facing slopes of Mount Somma at an altitude of about 1,000 metres, on shallow substrates and pyroclastic deposits. Despite its small extension, the hornbeam forest on Mount Vesuvius is the tallest trunk vegetation with the highest degree of naturalness.
Bladder (Colutea arborescens)
Family: Leguminosae or Fabaceae
Colutea L. is a genus which includes about twenty species of shrubs of the family of the Leguminosae or Fabaceae. The characteristic swollen shape of the fruits has earned this plant the common name of Vescicaria. It is native to Europe and North Africa, with an area centered on the Mediterranean coast, and is often used to control erosion. Heliophilous species, it grows in calcareous soils and especially on arid slopes, woods and especially in warm temperate climates; it is found in association with Black Hornbeam, Cornelian, from 0 to 1200 m of altitude.
The plant, which can reach 4-5 meters in height, has an erect stem and branched from the base, with light brown bark and branched at the top. The leaves, deciduous, are composed, pinnate, ovoid, full margin, with smooth upper page and the lower slightly glaucous and pubescent.
The yellow flowers are hermaphrodite, grouped in short racemose inflorescences, placed at the axil of the leaves and provided with a long petiole of 1,5 cm; they have the characteristic papilionaceous shape of most of the leguminous plants. The legume, 7-8 cm long, is swollen with a turgid and membranous appearance, similar to a more or less transparent bladder and of parchment consistency and of a reddish brown colour which, when ripe, hangs from the branches.
In the Vesuvius National Park it is a little diffused shrub formation, which however evolves more or less rapidly towards more complex formations; the populations, distributed in small nuclei, are concentrated mainly on the more steep southern slopes of Mount Somma, in association with Broom of the charcoal burners (Cytisus scoparius) and Common lair (Rubus ulmifolius).