Noteworthy is the complex of ipsophytes that populate the alpine area of Sardinia and Corsica above the belt of Alnus suaveolens . According to themeparktour, the analysis made for this last island by Briquet reveals the various components, among which the boreal-alpine and the alpine are not missing, but it is worth noting the lack of richer genera, especially in the Alps ( Campanula , Gentiana , Pedicularis , Primula , Androsace , etc.). At least thirty endemics, some of which are certainly paleogenic, and the rare Delichrysum frigidum W. of the section is valid for all. Virginea DC. which includes the nominated, the H. virgineum Boiss. of the alpine area of M. Athos, the H. Amorginum Boiss. et Orph. of the island of Amorgos (Cyclades) and the H. Billardieri Boiss. et Bal. of Lebanon. But even more conspicuous is the contingent of endemic forms of the mountain area in the two islands, some of which rise up from the coast and, taking into account what has already been said about the wealth of Mediterranean endemisaries, it is legitimate to conclude that the Corsican-Sardinian archipelago represents from we have the maximum concentration of its own species, many of which are of an archaic type.
To the news on the various terrestrial areas it is useful to add those relating to the areas covered by marine or fresh waters and involving plants immersed in the waters but adhering to the banks, plants suspended in the water, the so-called phytoplankton , and bottom plants constituting the phytobenthos . In sea waters at a depth of no more than 30 m. very few seagrasses live, of which the most common are: Posidonia oceanica , Cymodocea nodosa , Zostera marina and nana which form vast underwater meadows and, with the exception of the first, also in lagoon bottoms with the addition of Ruppia maritima and sometimes of Zannichellia palustris. On the other hand, there are many algae. For those adhering to the coast, a littoral or intertidal zone has been distinguished, alternatively uncovered or covered by the tide; an area between this and the depth of 5 m; one up to a depth of 35 m; and finally a last one between the altitude 35 and the lower limit which in general does not exceed 150 m. In the first two areas the Chloroficee prevail, in the last two the Rodoficee; the Feoficee are mainly in the intermediate levels, but in general almost all the cenoses contain a varied mixture of the three types and everything is reduced to the different proportions of the same. Also for the algae, which although they lend themselves to an easy transport, we note singular localizations and, therefore, endemic forms. One of these is Fucus virsoides (Don.) Ag. So frequent and exclusive of the intertidal zone of the upper and middle Adriatic, but which on the other hand is similar to species of the North Atlantic. Thus in the Gulf of Rijeka the influx of cold groundwater determines the appropriate conditions for the existence of the Diatom Thalassiothrix Nitzschioides and of several naviculoids of the northern seas certainly not imported by current currents, because these currents do not reach the Adriatic, but there it is also some representation of oriental types carried by coastal currents and this recalls the already mentioned case of Apocynum venetum .
But many algae (especially Chloroficee, Diatoms, etc.) are inhabitants of fresh waters and, therefore, of lakes, ponds, swamps, streams, etc. which also offer various ecological conditions to other cellular cells (lichens, mosses, etc.) and to the same superior plants that are usually distinguished into hygrophilous and hydrophilic. Interesting is what is observed in the lakes in which limnologists have recognized: the shore or beach that is unsinkable or only temporarily submerged; the coast from this to a depth of 15-30 m .; a benthic area from the latter level to the bottom; a limnetic zone comprising the mass of water occupied by planktonic organisms. The succession of vegetation belts varies, but one of the most frequent is, for the hygrophilous, the cariceto-fragmiteto-scirpeto series (with predominance, respectively, Carex , of the common reed or Phragmites communis and of the Scirpus lacustris ) and for the hydrophytes the series nimfeeto or nenufareto-potamogetoneto or potameto-caraceto including rooting plants at the bottom or suspended with leaves resting on the surface of the waters, such as Nymphaea alba and the Nuphar luteum (lamineto), or with the body totally submerged as is the Vallisneria spiralis and as are the Chara , the Nitella , etc., constituting the caraceto with which they end at a depth of 20-30 m. macrophytes. Many lake basins are surrounded by peat bogs or are independent of them: they are made of mosses with a prevalence of Polytrichum (polytricheti) and Sphagnum (spagneti) which maintain a perennially humid substrate on which mountain and alpine hygrophytic species settle including Drosera and Pinguicola , known insectivorous plants (see carnivore, plants), while Aldrovanda and Utricularia are submerged carnivores . The lowland peatlands such as in Padania, Tuscany, Lazio and the Pontine Marshes, host a certain number of orophytes whose lowering is believed to have occurred in glacial crises and which have been able to maintain thanks to the perennially soaked substrate. They are the microthermal colonies and among the most characteristic species we remember: Deschampsia caespitosa , Carex Davalliane, Eriophorum latifolium , Gymnadenia conopsea , Caltha palustris , Drosera rotundifolia , Gentiana pneumonanthe , Pedicularis palustris , Cirsium palustre , etc. Even the watercourses have hydrophilic consortia on the type of lacustrine with various adaptations of the species to the movement and depth of the waters, and rich is the bank and alluvial flora based on willows, poplars, alders which they mix, in many of the furrows valleys of the Alpine sector and of the northern and central Apennines, the Hippophaë rhamnoides and Myricaria germanica which are steppe elements penetrated by coastal districts; and in fact the first is found here and there in the Veneto-Po Valley estuary: but the streams of water robbing fruits, seeds or even entire plants of elevated areas and placing them in the lower course, contribute to lowering the limits and creating more or less heterotopic stations. less stable.
