Vegetation of the Maltese Islands 
Edwin Lanfranco, Department of Biology, University of Malta

Introduction 

The position of the Maltese Islands in the centre of the Mediterranean gives a special significance to their flora. The Maltese flora partakes of the floras of all the other parts of the Mediterranean and thus one finds species with eastern, western and North African affinities. As is to be expected the Maltese flora is most similar to that of Sicily, especially to that of the Hyblean Region (south-eastern Sicily) to which the Maltese Islands were intermittently attached until about 12,000 years ago. The Maltese vascular flora comprises about 1,000 species of which some 800 are indigenous, the rest being naturalised aliens (see below). 

The Maltese climate can be considered to be average for the Mediterranean region. Temperatures rarely fall below 50 C (although grass temperature occasionally falls below zero in winter) and rarely rise above 350 C.  The average annual rainfall is 513mm but evapotranspiration may reach 942mm.   There is thus great dependence on water from the sea-level water table which is generated by seepage of seawater into the rock. 

The Maltese Islands are composed entirely of Oligo-Miocene sedimentary rocks which are largely of marine biogenic origin. These are highly calcareous thus giving rise to alkaline soils with a pH generally ranging from 7.0 to about 8.5. From the lowest to the highest, the rock strata are: Lower Coralline Limestone, Globigerina Limestone, Blue Clay, Greensands and Upper Coralline Limestone. The Coralline limestones are hard rocks and they give rise to a karstic landscape wherein the effect of rain over the millennia has produced a system of depressions in which soil accumulates. Karstlands support a garigue or rocky steppe vegetation. The small size of the Islands coupled with their low altitude (the highest point is only 153m above sea level) means that all parts are influenced by the surrounding sea and soils may be somewhat saline. There is considerable exposure to strong winds, especially north-easterly. Thus the plant life of these islands has to be adapted to withstand all these stresses. 

The Maltese Islands were colonised about 7,000 years ago by immigrants who already had a sophisticated agricultural technology and who eventually created the Temple Culture.  Renfrew (in Before Civilisation) estimated that during the Temple Period Malta supported some 11,000  inhabitants. Thus the Maltese Islands have been under heavy anthropic pressure since their colonisation, to a much greater extent than other Mediterranean islands of comparable size have been. 

Maltese Woods and Maquis 

The Evergreen woods have been virtually destroyed. The few small populations of the Evergreen Oak (Quercus ilex), some of great age, are possibly the remnants of woods which existed up to a few hundreds of years ago. The Aleppo Pine (Pinus halepensis) had been totally destroyed but several replantings have taken place and there are now some areas, notably Buskett and Mizieb, which have taken on the character of a wood. 

The maquis vegetation is still widespread especially on the sides and bottoms of the dry valleys or widien (singular: wied). However all our maquis is of secondary origin and is dominated by trees such as the Carob (Ceratonia siliqua) which are not really indigenous but which were introduced in antiquity because of their utility. Other components of the maquis are the Lentisk (Pistacia lentiscus), Bay Laurel (Laurus nobilis) and the Olive (Olea europaea). Due to the recent drastic reduction in grazing there has been some regeneration of maquis and some formerly uncommon species such as Mediterranean Buckthorn (Rhamnus alaternus) and Terebinth (Pistacia terebinthus) are starting to increase. Particularly interesting is the Alerce or Sandarac Gum tree (Tetraclinis articulata), a conifer related to the Junipers. This tree has a Maghrebian distribution with Malta and an area in Murcia as the only European stations.  Several hundreds of years ago it must have been widespread in the Maltese Islands but it is now very rare. It forms a maquis on rocky slopes. 

The Garigues 

The garigue is the most typical of the Maltese vegetational communities and is characteristic of the karstic rocky regions of the islands. Nevertheless the garigue community is fast declining to the incursions of the building industry, new roads, dumping and other forms of habitat disturbance. The most important shrubs of the Maltese garigues are the Mediterranean Thyme (Thymus capitatus), Mediterranean Heath (Erica multiflora), Yellow Kidney Vetch (Anthyllis hermanniae), the endemic Maltese Spurge (Euphorbia melitensis), Tree Spurge (Euphorbia dendroides) and Olive-leaved Germander (Teucrium fruticans).   Some rare formations also feature Rock-Roses (Cistus incanus and Cistus monspeliensis). Herbaceous species are numerous and many of these also occur in rocky steppes and open maquis. 

The Steppes 

Steppe vegetation is very widespread with a great diversity of species. Dominant steppe grasses are Stipa capensis, Hyparrhenia hirta, Brachypodium retusum. Thistle steppes are dominated by Carlina involucrata, a North African species which in Europe seems to occur only on the Maltese and Pelagian islands. The commonest geophyte is the Branched Asphodel (Asphodelus microcarpus), which is abundant on ground which is frequently burnt, although numerous other species occur. A particularly interesting steppic community occurs on clay slopes. This is usually dominated by Esparto Grass (Lygeum spartum). 
 

Cliff Communities 

Cliffs are an important feature of Maltese topography and occur along the south and west of Malta, and much of Gozo and Comino. Their vegetation may be considered as a special kind of maquis or garigue, depending on the Size of the plants. But the flora is especially interesting since it includes many of our endemic species and species of North African affinity. Characteristic cliff species are the Maltese Rock-Century (Palaeocyanus crassifolius), Maltese Salt-Tree (Darniella melitensis) and Maltese Cliff-Orache (Cremnophyton lanfrancoi) all of which are endemic, as well as Caper (Capparis orientalis) and Sea Carrots (species of Daucus which still need to be investigated). 

Other communities 

Malta also has wetland communities, saline marshlands and coastal sands, although none of these habitats are particularly common. Much of the vegetation of such communities in the Mediterranean is very similar to that of like communities in continental Europe. All our saline marshlands have been heavily degraded by human interference, although some of these have been or are being rehabilitated as nature reserves. Their vegetation is dominated by various Chenopodiaceae and Rushes. Some valleys support temporary water courses or small permanent springs and here the vegetation is mainly characterised by Reeds (Especially Arundo donax), Sedges, Grasses and Rushes. The Southern Reed-Mace (Typha domingensis), once rare, is on the increase in several water courses and ponds. A few of these also support some deciduous trees such as White Poplar (Populus alba) and Hoary Elm (Ulmus canescens) which are rare.    The Willows (Salix alba and Salix pedicellata) are close to extinction although environmental NGO’s are undertaking attempts at propagating them.  

An interesting type of wetland is associated with the karstlands where some of the depressions in the rock fill up with rainwater. These temporary rock pools support an extremely interesting flora and fauna. The flora includes Mediterranean  Starfruit (Damasonium bourgaei) which has a very restricted Mediterranean distribution and the Maltese Waterwort (Elatine gussonei) which is a Pelago-Maltese Endemic (= endemic to the Maltese and the nearby Pelagian Islands). 

Sand dunes have suffered greatly in the past fifteen years and their flora has been greatly impoverished, except at the Ramla in Gozo. The Marram Grass (Ammophila littoralis) seems to have become extinct. The dominant species of extant dunes are Couch Grass (Elytrigia juncea), Dropseed Grass (Sporobolus arenarius), Sea Kale (Cakile maritima) and Sea Daffodil (Pancratium maritimum). 

Disturbed Ground  

Due to the high degree of human impact, this habitat has become the most widespread over the islands and the most familiar wild plants are those encountered on disturbed ground. Many of these species are aliens or adventives which have become naturalised over the years. Thus the most common of Maltese wild plants, the Cape Sorrel (Oxalis pes-caprae) is actually a native of South Africa and was only introduced into Malta at the beginning of the nineteenth century to be cultivated at the botanical garden. From Malta it has spread all over the Mediterranean and along the atlantic coast of Europe and can now be found also in the south of England. The Crown Daisy (Chrysanthemum coronarium) is possibly native to the Orient and was probably introduced several hundreds of years ago. The Narrow-leaved Aster (Aster squamatus), which has now overrun the country was only introduced in the 1930s. The Tobacco Tree (Nicotiana glauca) was introduced as an ornamental, but is now extensively naturalised especially on rubble. The same applies to the Castor Oil Tree (Ricinus communis) which has spread rapidly and which even invades valleys. 

Affinities 

As stated above the Maltese flora partakes of that of all other parts of the Mediterranean. Thus the Alerce (Tetraclinis articulata) is north-east African (Maghrebian); the African Tamarisk (Tamarix africana) and the Mediterranean Willow (Salix pedicellata) are western Mediterranean species.    Olive-leaved Bindweed (Convolvulus oleifolius) and Yellow Kidney-Vetch (Anthyllis hermanniae) are eastern Mediterranean species.   The Egyptian St. John’s Wort (Hypericum aegypticum), Rock Crosswort (Crucianella rupestris) and Wolfbane (Periploca angustifolia) are essentially North African species. 

Endemism  

The Maltese Islands have a lesser degree of endemism than most comparable Mediterranean territories. This may appear strange at first since these islands are also the most isolated and thus would be expected to have a higher degree of endemism. This situation has probably arisen due to the intense human influence on the environment and it is not improbable that some particularly vulnerable endemic species have been lost. Nevertheless the isolation of the islands has left its mark on our few endemic species, two of which are assigned to monotypic genera (= genera with only one species):  Palaeocyanus and Cremnophyton.   Below is a list of the known endemic species (and subspecies), including the authors of the names, grouped according to family.   The English names are as given in the Red Data Book of the Maltese Islands. 

Family Alliaceae (Onion family) 
Allium lojaconoi  Brullo, Lanfranco & Pavone   [Maltese Dwarf Garlic] 

Allium melitense  (Sommier & Caruana Gatto);  Ciferri & Giacomini  [Maltese Leek] 

Family Asteraceae (= Compositae;  Daisy family) 
Anthemis urvilleana (DC.) Sommier & Caruana Gatto   [Maltese Sea-Chamomile] 

Chiliadenus bocconei  Brullo    [Maltese Fleabane] 

Helichrysum melitense  (Pignatti) Brullo, Lanfranco, Pavone & Ronsisvalle [Maltese Everlasting] endemic to Gozo 

Hyoseris frutescens  Brullo & Pavone    [Maltese Hyoseris] mainly in Gozo 

Palaeocyanus crassifolius  (Bertoloni) Dostol [Maltese Rock-Centaury] Malta’s "National Plant" 

Family Brassicaceae (= Cruciferae; Cabbage family)   
Matthhiola incana  (L.) R Brown subspecies melitensis Brullo, Lanfranco, Pavone & Ronsisvalle 
[Maltese Stock] mainly in Gozo 

Family Chenopodiaceae (Spinach family)  
Cremnophyton lanfrancoi Brullo & Pavone   [Maltese Cliff-Orache]  

Darniella melitensis (Bochantzev) Brullo [Maltese Salt-Tree] 

Family Euphorbiaceae (Spurge family) 
Euphorbia melitensis Parlatore 

Family Iridaceae (Iris family) 
Romulea melitensis B,guinot [Maltese Sand-Crocus] 

Family Orchidaceae (Orchid family) 
Anacamptis urvilleana Sommier & Caruana Gatto [Maltese Pyramidal Orchid] 

Ophrys sphegodes Miller subspecies melitensis Salkowski [Maltese Spider-Orchid] 

Family Plumbaginaceae (Sea-Lavender family) 
Limonium melitensis Brullo [Maltese Sea-Lavender] 

Limonium zeraphae Brullo [Zerafa’s Sea-Lavender] 

In addition to the above there a few plants which have been described at the level of form, making them just local races. There may also be some other endemic species which are as yet undescribed such as some wild carrots (Daucus) which grow on cliffs and at least two other types of Limonium

Apart from the strict endemics there are also a number of other species of very restricted Mediterranean distribution. One may single out the Maltese Toadflax (Linaria pseudolaxiflora Lojacono);  Maltese Waterwort (Elatine gussonei (Sommier) Brullo,  Lanfranco, Pavone & Ronsisvalle) and the Lampedusa Carrot (Daucus lopadusanus Tineo) which are endemic to the Maltese and the Pelagian Islands. Pignatti’s Ferngrass (Desmazeria pignattii Brullo & Pavone) is endemic to Malta and the Hyblean region of Sicily while the Pygmy Groundsel (Senecio pygmaeus D.C.) and Sicilian Iris (Iris sicula Todaro) are endemics of Malta and Sicily. The Sicilian Squill (Scilla sicula Tineo) is known from Malta, Sicily and Calabria, but is relatively frequent only in Malta. The celebrated Malta Fungus (Cynomorium coccineum) is neither a fungus nor is it endemic to Malta. It was originally first described from the so-called Fungus Rock off Gozo in the Maltese Islands, where it still exists, but was subsequently discovered in several other islands and coastal localities all over the Mediterranean as well as in Marcaronesia and in salt-deserts of central Asia. It is a parasitic flowering plant which grows attached to the roots of a variety of halophytic (salt-loving) shrubs.