The Flora and Vegetation of Thera and Crete Before and After the Great Eruption

The paper considers other evidence for the vegetation of Minoan Thera, and makes suggestions concerning the landscape and the availability of trees.

The modern flora of Santorin is unexpectedly quite rich in species. Many of the plants have been introduced by human activities, but there is also a well-developed "'natural" flora. 

The paper considers the distribution of endemic plants in Crete and the Aegean in relation to possible destruction by ash from the explosion of Thera. The Ida and Lassithi regions are somewhat deficient in endemics, but not sufficiently to give positive evidence of a southerly distribution of fall-out. Karpathos and the Sitia Peninsula, which would have been affected by a south-easterly fall-out, are particularly rich in endemics.

PLANTS IN AKROTIRI

Pictures of plants form perhaps more of the art of the Minoans than of any other ancient people. They are the predominant decoration on walls and pots, and contrast with, for instance, the animals and abstract designs favoured by the Myceneans. Outside Crete, such pictures are known from Melos, from fragments on Kea and Rhodes, and from the 19th-century excavations on Santorin (Mamet 1874) but all these are greatly surpassed in number and variety by the finds at Akrotiri.

Most Minoan plants are drawn with at least moderate skill, and some give the impression of being astonishingly life-like; but, being works of art, they are stylized to varying degrees, and are not easy to identify. The pictures of lilies are an example. The Minoans knew two species: Lilium chalcedonicum L., the red lily, with drooping flowers, recurved petals, and a sharp distinction between upper and lower stem-leaves; and L. candidum L., the white lily, with upright flowers, spreading petals, and a gradual distinction between upper and lower leaves (Flora Europaea). Most pictures of lilies are of some combination of the two species. The Room of the Lilies at Akrotiri shows a red lily with its correct petals and stem-leaves in minute and seemingly life-like detail; but the flowers, although shown in various stages of opening, are all upright, a sure sign that the painter did not have the actual plant before him. On the Vase of the Falling Lilies (Thera IV, Pl. 83) the painter has very properly shown falling as well as fully-open flowers, but has overlooked the fact that lilies fall petal by petal and not all at once. Lilies, being a popular subject and available for only about a fortnight each year, would naturally be painted more often from memory or from a previous picture than from life. These difficulties with so distinctive a pair of species as the lilies are a warning against hasty attempts at identifying less familiar plants. Many plant names which have passed into the literature of Minoan art are unconvincing, and some identifications must forever remain in doubt.

Some 50 - 60 artefacts so far published or exhibited from Akrotiri depict plants. The artists appear to have had in mind some 25 different species. Many are too vague to be determinable, including the commonest of all, the generalized monocotyledonous plant depicted on pots (e.g. Thera II Pl. E3, E5). With others we have the product of a long tradition of stylization which may not even have begun in the Aegean. For instance, the so-called "ivy", one of the commonest motifs at Knossos (Cameron 1968), and at Akrotiri forming the border to the Antelope Fresco, is no plant known to science. Probably it was a species of Ruscus or a related genus that inspired the peculiar pattern of a cluster of flowers attached to the middle of a leaf-like object, but generations of repetition as a conventional border have shorn it of all the characteristics of a real plant.

Despite these difficulties we can identify some of the plants in the art of Akrotiri and can consider what part they played in the life of the inhabitants.

Agricultural crops are remarkably few. The most certain example is the pot with bunches of grapes (Thera III Pl. 56). The plant with stalked leaves having five palmate leaflets (Thera VII Pl. 15) may perhaps be hemp, Cannabis sativa L.; the cordage of the Thera Bed strongly suggests that this plant was available, although it is not recorded in cultivation before the 8th century B.C. (Godwin 1967). Several pots (e.g. Thera V Pl. 59b) have good representations of a legume with curved pod and asymmetrical calyx, probably some cultivated Vicia, although the features are common to many species.

Wild plants are also relatively few. One certain instance is the pot (Thera V Pl. 62c) with a detailed, and only slightly stylized, sketch of the remarkable fruit of Biscutella didyma L., a common ruderal in the islands. The same pot also shows what is probably the common wild bulb Gagea graeca (L.) Terrac. ( = Lloydia graeca L.). The "barley" motif (e.g. Thera II Pl. 36) looks more like the common wild grass Bromus madritensis L. (? B. rubens L.: Greuter & Rechinger 1967) than any cereal.

Garden plants are most obviously represented by the red and white lilies.

From all the literature (Boissier 1875, de Halácsy 1902, Rechinger 1943, Turrill 1954, Stearn 1969, Flora Europaea) it is clear. that Lilium candidum and L. chalcedonicum uncommon as indigenous plants, growing in a few places on the Greek mainland but on none of the islands except Euboea. There is no reason to suppose that they were ever more widespread; indeed L. candidum may have increased its range through escapes from cultivation. The Minoans can have known lilies only as garden flowers; they would probably have needed watering to survive the Cycladic summer. The many pictures of species of Crocus, Sternbergia or Colchicum could be either wild or garden plants. The latter is strongly indicated by the fresco of the Women Gathering "Saffron" : whatever the plant is (when the original fresco becomes available it should be possible to identify it) the ladies are clearly dressed for a garden-party rather than for roughing it in the phrygana. The Minoan attitude to gardens is also illustrated by the Amnisos Lilies, depicting a vase of cut flowers on a windowsill, and by the many pots with holes in the bottom presumably used as flower-pots.

The final category is that of foreign plants unlikely to have grown in the Aegean. The Miniature Fresco depicts two kinds of palm-tree; one with a tall relatively smooth trunk, the other with a short trunk covered with the stubs of old leaf-bases. These are not palms in a state of nature, in which the trunk is concealed by a mass of dead fronds; they seem to be cultivated date-palms, in which, as is still the custom, the dead fronds are cut off leaving stubs, which later fall away to reveal the smooth trunk. The shorter trees are young ones in which only the first stage has so far taken place. The native Cretan palm, Phoenix theophrasti Greuter, is hardly edible and is unlikely to have been deliberately tended (Greuter 1967); moreover all writers from Classical times onwards have been stuck by its forking habit which is not represented here. This is more likely to be a scene in North Africa or the Middle East, as is suggested also by the lion, fallow deer and papyrus. The palms must have been drawn by someone who had seen them growing and recognized the cultural practice. A fragment of another fresco (Thera II Pl. B3) also shows the "tall" kind of palm-tree.

Another presumably exotic plant is the papyrus in the Fresco of the Ladies. The identification with Pancratium maritimum L. is undoubtedly erroneous (Warren 1977) ; that plant is much too small, is very different in habit and colour, and has an umbel of at least three flowers. The plant in the fresco is Cyperus papyrus L., shown moderately stylized by an artist who had evidently not seen it; this is one of many more or less conventionalized Minoan and Mycenean pictures of papyrus. The plant is African, with outlying localities in Sicily; it could hardly have grown wild in the Aegean because of the lack of wet-lands.

The vegetable art of the Minoans is a curious anticipation of the pottery and wallpaper of 19th-century England. There is the same tendency to stylize; but insofar as the plants are real they reflect a taste for gardening and travel rather than an interest in field crops or the native vegetation.

THE VEGETATION AND RESOURCES OF MINOAN SANTORIN

Before human settlement the island would have been a volcanic cone with small marble outcrops. In phytosociological theory the natural lowland vegetation in this climate ought to have been an evergreen forest dominated by the oaks Quercus ilex L. and Q. coccifera L. Both of these grow, for example, in modern Naxos, though ilex survives only at high altitudes. Deciduous trees might have covered the top of the cone if high enough. Owing to the isolation of the island, its recent geological origin, the severe wind exposure, and periodic devastation by eruptions the forest was probably very patchy and may have lacked some of the trees. Naxos has a fairly full range of trees but modern Ios is probably a better parallel. On Ios the only oak I have seen is one old Q. ilex, some 30 cm high, on the highest summit; in default of oak the nearest approach to natural woodland is dominated by the evergreen Arbutus unedo; the only other trees are scattered individuals of Juniperus phoenicea.

Direct evidence for the vegetation of Bronze Age Santorin is scanty. Mamet (1874) reported the stump of an oak (truncus quercus) in the settlement he excavated at Akrotiri, as well as a rope of tree-bark and various cultivated grains; on Therasia he reported "branches of vine and olive" used as interlacing for stone walls. No identification details are given; it is possible that the "vine-branches" were really Arbutus or Juniperus, both of which look superficially like Vitis. The olive evidence was supported by a find of olive-stones.

The recent Akrotiri excavations reveal a moderate amount of structural timber in buildings. The evidence so far published is all from casts; the species cannot be identified. Floors and flat roofs were supported by beams up to about 20 cm thick. There were wooden frames to doors and windows and occasional bonding-timbers in some walls. Some of the timbers were round in section and some squared. Floor-structures (Thera VI Pl. 41a, VII Pl. 24) incorporated branches of trees with an attached heel where cut from the trunk. Reeds (Arundo donax L.) were occasionally put to minor structural use (Thera III Pl. 47, IV Pl. 31b, VI Pl. 22). Dung may possibly have been used for fuel (Thera VII pl. 21).

This suggests that Akrotiri was better off for timber and wood than the Early Bronze Age settlement at Myrtos, with its short spans and extensive use of reeds and olive prunings (Rackham 1972), but - considering the high quality of the buildings - was less well endowed than settlements such as Early Bronze Age Vasiliki (Seager 1905, 1907) with its lavish timber-framing. In general, and even in many details, the timber fabric at Akrotiri was remarkably like that in modern Chora, los, where floors and roofs are supported by poles or beams of oak, olive, or juniper, on which are laid at right angles either schist slabs, or reeds, or branches of olive, juniper, or Arbutus, overlaid with hay and packed up level with earth.

Although only a minute fraction of the original surface of Thera is now accessible, at least four settlements are known. Before the explosion the island must have been thickly peopled with villages and farms; a scene, probably, of rugged fertility like north-east Naxos today. In the modern Aegean, there are two types of woodland: remnants surviving by accident in very inaccessible places, as on the formidable screes of Mount Zeus in Naxos; and groves (or isolated trees) amid farmland, often on rock outcrops and in gullies, protected from indiscriminate grazing through being surrounded by arable, and forming a permanent source of timber and firewood. It is unlikely that any of the former would have remained in a densely-populated island, but there may well have been a good deal of woodland of the latter type, besides the olive groves and village trees of which we have direct record. We cannot yet say whether it was necessary to import timber from elsewhere. The only certain evidence of timber importation in the Minoan world appears to be the early but well-authenticated identification of small quantities of the non-Cretan trees Abies, Picea, and Cedrus from a few sites in Crete (Netolitzky 1934).

The Fresco of the Lilies is our nearest approach to a representation of what part of Thera looked like before the explosion. The landscape, with its fantastic multicoloured rock pinnacles and overhangs, seems at first sight to be a work of pure invention; but as it happens there is one place on the island, less than 1 km west of the site. to which it corresponds remarkably closely. A sharp ridge of rock, part of an old lava-flow, juts into the sea; it is coloured black, red, and yellow, just as in the fresco, and the cavernous decay of the lava has created just such improbable pinnacles and overhangs. This bluff is part of the old land-surface, and must have been more prominent before the surrounding land was buried in ash. There can be little doubt that the fresco was inspired by this specific place even though the artist has transmuted the humble asphodels and squills which form its scanty natural vegetation into gorgeous red lilies.

THE MODERN FLORA OF SANTORIN

The plant list by Hansen (1971) enumerates 487 species of flowering plants and ferns. This is the accumulation of many botanical visits, but although Santorin is comparatively well known the list is certainly not complete. The distinguished botanist Heldreich in 1895 - 8 found only 240. In March 1977 I added 13 species (Appendix), making 500 in all. The curve of Fig. 1 suggests that the list will eventually reach 550 species, even allowing for the probability of misidentifications among some of the old records.

The list is remarkably long, considering that the island is small and remote, is very highly cultivated, has been devastated by a volcanic explosion, and has no native trees and little semi-natural vegetation. The comparably-studied island of Kythera, four times the size and having none of these disadvantages, has 564 species according to Greuter & Rechinger (1967) - only 12 % more than Santorin. 

Most Santorin plants are widespread in the Aegean. As Greuter (1971a) reminds us, many island plants have been introduced by human activities; some are weeds of, or escapes from, cultivation; others are dependent on buildings, roads, middens, and other artefacts. Most wild plants of the villages and countryside of Santorin come into this category, as do some of those on cliffs and the volcanic rubble of the Kamenes (an alternative habitat for many agricultural weeds). An obvious example is Opuntia ficus-indica (L.) Miller from North America, originally cultivated and now well established on cliffs.

There is a large residue of plants not obviously connected with human activity. The marble outcrops of Prophetes Elias, Mesavouno, and Monolithos, though only 3.5 sq. km in extent, have a well-developed phrygana and rock-crevice flora; about 80 species are confined to them. Anaphi, the nearest source, is 21 km across the sea, and it is just possible that some of these plants might have survived the explosion, particularly the bulbs if they happened to be dormant at the time. The most likely example is Muscari theraeum Heldr., which is apparently found nowhere else. Although in Flora Europaea this is no longer thought sufficiently distinctive to count as an endemic species, it remains unlikely that such a population could have been generated by evolution in plants arriving from Anaphi after the explosion.

THE EXPLOSION AND THE ENDEMIC PLANTS OF THE AEGEAN

It is often supposed that the great eruption of Thera, as well as depositing volcanic ash on the sea-bed to the east, and especially to the north-east, of Crete (Ninkovich & Heezen 1965) also covered the immediately adjacent land with ash, which, though it has since vanished, was sufficiently thick to interfere with agriculture and thus to bring about the collapse of Minoan civilization.

Some 200 species of flowering plants are endemic to the Aegean islands, i.e. are found nowhere else in the world. Many are endemic to particular islands and often to very small areas, and are vulnerable to catastrophes. An ash fall-out severe enough to prevent agriculture ought to have brought about the extinction of some of the endemics. The endemic plants are generally supposed to have been in position throughout the Pleistocene and such a loss could not have been made good in a mere 3500 years. Even if other populations remained on unaffected islands, endemics - which, almost by definition, have very limited powers of dispersal - ought not to return to localities from which they have disappeared.

Crete may be divided into the west, with the White Mountains; the middle, Mount Ida; the east, with Mount Dhikti; and the far-eastern Sitia Peninsula.

Table 1 shows for each region the number of narrowly endemic species - confined to one region only - and the number of species which, though endemic to Crete, also occur in one or more of the other regions. The information is derived from Flora Europaea, with a few additions from subsequent publications; the distributions have been checked chiefly against Rechinger (1943). Since authoriries sometimes disagree about what consitutes a species I give separate figures for subspecies and for species not accepted by Flora Europaea. I also give some similar figures compiled on a slightly different species basis by Greuter (1971 b).

TABLE 1: Distribution of endemic species within Crete

* The first of each pair of figures is the number of recognized species; the second figure is the additional number of subspecies and rejected species.

** 11 endemics which are widespread in lowland Crete, and which might therefore be expected to recolonize easily, are omitted.

Table 2 gives similar statistics for all the islands in the South Aegean which have appreciable numbers of endemics.

The biggest concentration of endemics, on any basis of comparison, is in Western Crete. Middle and East Crete are roughly equal in broad endemics but much poorer in narrow endemics. The Sitia Peninsula has more narrow endemics than the middle and east combined, but is poorer in broad endemics. Outside Crete the richest island is Karpathos, followed by Naxos, Amorgos, Kythera, and then Rhodes and Pholegandros.

Endemics tend to grow at high altitudes or in mountainous terrain. Within Crete the distribution of broad endemics follows the geography very closely; the west has the highest and most extensive mountains, the middle and east are slightly less mountainous, while the Sitia Peninsula is much smaller and is not high enough to have alpine plants. In narrow endemics, however, Middle and East Crete are much poorer than Sitia and even poorer than Karpathos. Away from Crete most endemic plants occur in the more mountainous islands.

It is uncertain whether anywhere in the Aegean a lack of endemics can reasonably be attributed to ash fall-out. Sitia and Karpathos, nearest the seabed deposits, have more narrow endemics than anywhere in the South Aegean except West Crete. The shortage of narrow endemics in Middle and East Crete - plus the five species which grow in both West and Sitia but are missing from Middle or East or both - might have been produced by a mainly southward pattern of fall-out on land. But the evidence is hardly conclusive, for we should have to suppose that the devastated regions had been very effectively recolonized by broad endemics from the rest of Crete, which is unlikely since many are alpine plants which could hardly have crossed the intervening lowlands except during the height of a glaciation.

TABLE 2 : Distribution of endemic species on various Aegean Islands.

Each region of Crete is treated as if it were a separate island. Species which are recorded from more than four islands (or regions of Crete) are excluded.

APPENDIX

Additions to the flora of Santorin, March 1977 (named as in Flora Europaea):

-    Allium staticiforme

-    Anthemis ruthenica

-    Bromus hordeaceus ssp molliformis

-    Evax contracta

-    Hypecoum imberbe

-    Mandragora autumnalis

-    Muscari cycladicum

-    Nonea pulla

-    Ononis pubescens

-    Paronychia echinulata (Nea Kaimeni)

-    Scilla autumnalis

-    Scorzonera ?cretica

-    Vicia peregrina

Plus Pinus brutia, almost certainly planted.

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