Phoenix dactylifera L., Sp. Pl. : 1188 (1753)

Primary tabs

https://media.e-taxonomy.eu/palmae/photos/palm_tc_152659_6.jpg

Content

Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)
Algeria present (World Checklist of Arecaceae)B
Benin present (World Checklist of Arecaceae)B
California present (World Checklist of Arecaceae)B
Canary Is. present (World Checklist of Arecaceae)B
Cape Verde present (World Checklist of Arecaceae)B
Egypt present (World Checklist of Arecaceae)B
Fiji present (World Checklist of Arecaceae)B
Gulf States present (World Checklist of Arecaceae)B
Iran present (World Checklist of Arecaceae)B
Iraq present (World Checklist of Arecaceae)B
Libya present (World Checklist of Arecaceae)B
Madeira present (World Checklist of Arecaceae)B
Mauritius present (World Checklist of Arecaceae)B
Morocco present (World Checklist of Arecaceae)B
New Caledonia present (World Checklist of Arecaceae)B
Oman present (World Checklist of Arecaceae)B
Pakistan present (World Checklist of Arecaceae)B
Réunion present (World Checklist of Arecaceae)B
Saudi Arabia present (World Checklist of Arecaceae)B
Sinai present (World Checklist of Arecaceae)B
Socotra present (World Checklist of Arecaceae)B
Somalia present (World Checklist of Arecaceae)B
Spain present (World Checklist of Arecaceae)B
Turkey present (World Checklist of Arecaceae)B
The natural distribution of P. dactylifera is not known. The long history of date palm cultivation in the Middle East and North Africa has extended the distribution of the species far beyond its presumed original range, such that its area of origin remains a mystery. It is doubtful whether P. dactylifera still exists in the wild. Zohary & Spiegel-Roy (1975) claim that 'spontaneously-growing dates can be found throughout the range of date cultivation'. Many of these 'wild' date stands may represent long neglected palm groves or escapes from such groves. In some areas of the Near East date palms can be found occupying primary niches and could perhaps represent wild P. dactylifera (Zohary & Hopf 1988).
CULTIVATION. Traditional areas of date palm cultivation have included the Middle East, Near East, North Africa, parts of north western India and Pakistan (Malik 1984). More recently, date palm cultivation has been established on a commercial level in California. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Discussion

  • HUMAN SELECTION OF THE DATE PALM. The suckering habit of P. dactylifera makes it well-suited to vegetative propagation and domestication. Date palms produce offshoots at the trunk base allowing simple clonal propagation of chosen palms. Selection of productive palms in combination with artificial pollination techniques has led to the development and recognition of hundreds of date palm cultivars, differing in fruit characters such as size, texture, fleshiness, colour, taste, sweetness and storage quality.
    INFRASPECIFIC NOMENCLATURE. Few of the hundreds of date palm cultivars have been formally described. Study of cultivars has been restricted to a local or regional level, so that there is inconsistent and differential use of vernacular and cultivar names between regions, and even palm groves. A proliferation of names can arise when date palms of identical stock are distributed to groves with varying microclimates, resulting in phenotypic variation (Brac de la Perriere 1988). Traditionally, date palm cultivars have been classified according to moisture content which, in turn, defines use. In general, fruits are divided into three classes: dry dates, which require high temperatures and sun levels for maturation, and are easily stored; semi-dry dates, which are more moist, and also store well; soft dates which must be eaten fresh and therefore are less commonly exported. Popenoe (1973) listed 1500 'varieties' cultivated to varying extents throughout the zone of date palm growth, and noted that if all named 'varieties' were to be collected together they would number several thousands. The term 'variety' has not been clearly defined in respect to the date palm, and was used by Popenoe (1973) to refer to what I consider to be cultivars. Martius (1823 - 1853) described seven varieties of P. dactylifera, and Beccari (1890) a further two, using only loosely defined fruit characters. Many cultivars are potentially referrable to any one of these names because of the brevity of the descriptions so that the names are useless to date grower and botanist alike. Local studies aside, there have been no attempts to construct a workable, consistent infraspecific classification for P. dactylifera. The most comprehensive attempt at such a study is that of Popenoe (1973) who gave a concise overview of cultivar history, geography and origin, discussed the nomenclatural confusion that surrounds most varieties, listed 1500 names and described the most commercially important ones in greater detail. Phoenix dactylifera cultivar taxonomy has not been an aim of this monograph.
    HISTORY AND ORIGIN OF THE DATE PALM. Together with the olive, grape and fig, date palms were amongst the first fruit crops domesticated in the Old World (Zohary & Speigel-Roy 1975). The cultural and religious significance of date palms, over a recorded 5000 year history, reflects their economic importance. The date palm was associated with the primitive Semitic goddess (Ishtar or Astarte) who symbolised the creative force of nature (Popenoe 1973). In Muslim tradition, God created the date palm from dust left over after Adam was created, and Arabs consequently know it as the 'Tree of Life' (Goor 1967), a name that well suits its multiplicity of uses. The origin of the date palm has been much debated and suggested areas include desert northwestern Africa (Fischer 1882; de Candolle 1884), tropical North Africa (Schweinfurth 1873; Grisebach 1872), Arabia (Bonavia 1885), Babylonia (Hehn 1888), the Persian Gulf (Beccari 1890; Werth 1934; Popenoe 1973; Zohary & Hopf 1988), Southern Persia (Boissier 1882) and Western India (Hamilton 1827). To resolve this question a multi-disciplinary approach is advisable, combining evidence from botanical and ecological data with historical, cultural and archaeological information. Feral date palms occur throughout the range of cultivated date, notably in the southern, warm and dry Near East as well as the northeastern Saharan and north Arabian deserts. It is difficult to ascertain whether these represent wild plants or merely secondary escapes from cultivated groves. Zohary & Hopf (1988) claimed that true 'wild dates', bearing small dry, hardly comestible fruits, are found in some areas of the Near East, growing in deep ravines, cliffs, and inaccessible gorges, often indicating ground water. Baluchistan, lowland Khuzistan, and the southern base of the Zagros Range facing the Persian Gulf, in particular, were identified by Werth (1955) and Zohary & Hopf (1988) as areas supporting populations of 'wild dates'. Zohary (pers comm.) reported spontaneous 'wild dates' bordering the Dead Sea on both Israeli and Jordanian sides. These Dead Sea populations comprise equal numbers of staminate and pistillate palms, they are sexually-reproducing and occupy primary habitats, such as wet escarpments, gorges, springs and seepage areas, suggesting that they are wild. A paucity of morphological characters makes differentiation of wild from feral plants difficult. Molecular data from a wide range of domesticated, wild and feral date palms may offer new and useful information. Nuclear and chloroplast DNA regions sequenced in the current study show insufficient variation to be informative at the varietal level within P. dactylifera. Beccari (1890) looked to ecology to solve questions of date palm origins. Date palms thrive in hot, dry conditions with little or no rain, as long as constant moisture about the roots is available. Wet soil is required for seed germination and hot sun for ripening of the fruit. In the words of Pliny (see Rackham 1945): 'It likes running water, and to drink all the year round, though it loves dry places'. Theophrastus in his Enquiry into Plants (370 - 285 BC, see Hort 1916) was an early observer of the remarkable resistance of date palms to salinity, 'wherever date palms grow abundantly, the soil is salt, both in Babylon, they say, where the tree is indigenous, in Libya, in Egypt and in Phoenicia'. Beccari (1890) understood the ecological characteristics of date palms as indicating that P. dactylifera originated in a hot, dry land where the ground was wet and saline. The lands adjoining the Arabian Gulf fit these specifications exactly. Palaeobotanical data provides further support for a Near Eastern origin of the date palm. Solecki & Leroi-Gourhan (1961) found Phoenix pollen, comparable to that of P. dactylifera, in sediment samples taken from the Mousterian layer D in Shanidar Cave, northern Iraq, dating to thousands of years before the start of Neolithic agriculture, possibly suggesting the pre-agricultural existence of date palms in the Near East. The earliest definite signs of date palm cultivation were noted by Zohary & Hopf (1988) to appear in Chalcolithic Palestine around 3700 - 3500 BC, and there is early indication of a date crop from contemporary lower Mesopotamia. From the Bronze Age onwards, date cultivation has been well- established in warm areas of the Near East. Historical and cultural information must also be considered. Corner (1966) noted that 'the origin of the date-palm is as insoluble as ever and will remain so until there are minds commensurate with the contributions that palms have made to civilisation'. Study of early date cultivators, particularly the Assyrians, Babylonians and Phoenicians, their history, trade routes, language and culture can offer useful and complementary information to botanical data. Historical records report date palm cultivation by the Sumerians as early as 3000 BC in present-day southern Iraq (Nixon 1951). Around the same time, the Phoenicians arrived in Phoenicia ('The Land of the Date'), the area covering present-day Lebanon and parts of Syria. It is not known from where the Phoenicians came but certain traditions suggest the Persian Gulf. The name Phoenix, coined by the Greeks, supports the sea-going Phoenicians as early cultivators and traders of date palms and fruit. The Phoenicians travelled far, establishing trading posts and settlements along their route west through the Mediterranean. By identifying the Persian Gulf area as the home of the date palm, the natural distribution of P. dactylifera occurs at the western edge of that of P. sylvestris, the Indian date. All students of the genus have acknowledged the close resemblance of the two species (e.g., Beccari 1890; Corner 1966). Griffith (1845) found the two species to be indistinguishable, and Hamilton (1827) considered P. sylvestris to represent 'merely the wild plant of the same species with that which is cultivated in Arabia and Africa: but this culture has wonderfully improved the fruit'. Their close relationship is supported by morphological, anatomical and molecular data generated by the current study. Systematic analysis in this paper resolves P. dactylifera, P. sylvestris and R theophrasti in one clade. Phoenix sylvestris differs from the date palm primarily in its solitary habit, its short pseudopetiole with congested, conspicuously folded acanthophylls, its shorter infructescence peduncle bearing smaller fruits that are scarcely fleshy and non-comestible, and its ability to withstand wet conditions. It is not certain whether human selection over thousands of years could result in the differences between the two species; however, on consideration of the selective restrictions of clonal cultivation, it would seem that major morphological and physiological changes and adaptations would not be encouraged. Corner (1966) found the strictly solitary habit of P. sylvestris and its occupation of a different ecological niche as strong evidence against it as sister to the date palm. Whatever the history of the relationship between P. sylvestris and P. dactylifera, their similarity is beyond doubt, and the identification of the Irano-Arabian area as the home of the date palm, alongside the western limit of P. sylvestris, comes as no surprise. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Biology And Ecology

  • An old Arab proverb says of the date palm that 'its feet shall be in a stream of water, and its head in the furnace of heaven'. The ability of R dactylifera to thrive in hot, dry conditions with little or no rain, as long as there is constant moisture about the roots for healthy growth and seed germination, have made it the classic symbol of the oasis. Throughout its distribution the date palm is taken as a reliable indicator of ground water in wadis, crevices and rocky ravines. In addition to its resistance to hot, arid atmospheres, the date palm shows remarkable tolerance of high salinity and water-logging. Despite resistance to water-logging, date palms are very vulnerable to excess rainfall and high humidity. Nixon (1951) noted that date fruits mature properly only if rainfall during the fruit maturation period (July to October) is less than 1.5 cm. Date palms are best adapted to tropical or sub-tropical conditions where the average daily maximum temperature is over 35'C and frost is very rare (Nixon 1951).
    REPRODUCTIVE BIOLOGY. The date palm has long been thought to be wind- pollinated. However, there is evidence for both anemophily and entomophily in P. dactylifera and other species of the genus. The staminate inflorescences produce copious amounts of pollen, typical of anemophily. The grains lack a sticky pollen- coat and are at the lower end of the wind-borne size range. The pistillate flowers show less obvious adaptation to anemophily, lacking an extensive stigmatic surface for capturing wind-borne pollen. Furthermore, Uhl & Moore (1971) identified what could be interpreted as nectaries at the base of the ovary which could suggest entomophily. Many kinds of insects are frequent visitors to date palm inflorescences, but their role as pollinators has not been conclusively demonstrated. It seems that the pollination syndrome of wild date palms involves both anemophily and entomophily. Herrera (1989) reported that the only other European palm, Chamaerops humilis L., is also pollinated by a combination of insects and wind, and Henderson (1986) suggested that this is a common syndrome in palms. Many animals are involved in dispersal of wild dates, as is the case with most palms (Zona & Henderson 1989). Ridley (1930) recorded the dispersal of dates by bats (Rousettus aegyptiacus). Several authors (e.g., Parrott 1980) have noted partially- eaten dates impaled upon the sharp acanthophylls of date palm leaves and have attributed it, circumstantially, to the action of the Great Grey Shrike (Lanius excubitor). Cowan (1984) suggested that it is the action of the wind rather than shrikes which is responsible. The most significant role in date palm dispersal has without doubt been played by man. Date fruits are generally easily stored and transported, and have therefore been an important component of the Middle Eastern diet, particularly for long journeys across the desert. The Phoenicians were not only early date palm cultivators but great travelling tradesmen and were certainly responsible in part for the early spread of date palms. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Conservation

  • The conservation status of wild P. dactylifera is difficult to ascertain due to the continuing doubt as to whether it exists in that state. As a species, P. dactylifera cannot be considered threatened due to its extensive cultivation; however, positive conservation action may be necessary at the infraspecific level if diversity of date cultivars is to be maintained. Intrinsic within the hundreds of cultivars is a large reservoir of genetic diversity that has been the source of palms of varying vegetative and fruit characteristics for date palm growers through the ages. Recent years have seen a decrease in the number of varieties regularly propagated in cultivation. As with landraces and cultivars of all crops, active cultivation is vital to survival and a cultivar is soon lost for ever if it is not regularly propagated. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Common Name

  • The names listed here refer to P. dactylifera as a species. The serious student of date palm varieties and cultivars must look to Popenoe (1973) for a comprehensive list of vernacular names, and their meanings. ARABIA. Usteh-khurma (fruit), nukhal (leaves), (Arabic), [Beccari (1890)]. Egypt. Balah (date palm), (Egyptian), [Taickholm & Drar (1950)]. INDIA. Pind, chirwi, bagri (fresh dates), bela (dry dates), khajur, chuhara (leaves), gadda, galli (palm 'cabbage'), (Hindi); payr-etchum manam (leaves), (Tamil); kharjurapu chettu, perita chettu (leaves), (Telinga), [Beccari (1890)]. IRAQ. Nakhla/Nakhl, (date palm), tamr (fully ripe dates), rutab (fresh, edible but only half-ripe dates), kurjan, khurma (leaves), (Arabic), [Dransfield (1985)]; gutla-i-khaur, tukhm-i-khurma (fruit), (Arabic), [Beccari (1890)]. TURKEY. Khurma (date palm), (Kurdish, Turkish), [Dransfield (1985)]. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Uses

  • Commercially P. dactylifera is one of the most important species in the family, after Cocos nucifera L. (coconut) and Elaeis guineensisJacq. (oil-palm). Date palms have been cultivated in the Middle East and northern Africa for at least 5,000 years (Zohary & Hopf 1988). For some communities practising subsistence agriculture, the date crop provides an essential subsidiary income. The primary use of date palms is, of course, their nutritious fruit which is eaten fresh, dried or processed as one of a wide-range of date products. Date seeds are used as cattle fodder (seeds ground up or soaked in water or sometimes sprouted first), or are occasionally ground as a coffee substitute or adulterant, or for ornamental purposes (as jewellery). Stems are tapped for the sweet sap (date 'honey') which can be drunk fresh, or processed as sugar or fermented into a highly intoxicating beverage, referred to as 'The Drink of Life' in cuneiform inscriptions of the ancient Egyptians (Tickholm & Drar 1950). Tapping interferes somewhat with fruit production, and the number of times a palm can be tapped is limited. In addition to the fruit, vegetative parts of the date palm are put to many and diverse uses including building materials (leaves, trunks), fencing (leaves, midribs), thatch (leaves), rope (leaf sheath, leaflet and midrib fibres), fuel (all vegetative parts, but especially leaf- bases); packaging, padding and protection (leaf sheath fibre). The terminal bud can be eaten as a sweet, tender vegetable, though rarely so because only non- productive palms would be felled for such a purpose. Cutting of the terminal bud leaves a cavity which fills with a thick, sweet refreshing fluid that is drunk fresh or fermented. The palm is important in several Christian, Jewish and Muslim festivals (Goor 1967; Nixon 1951; Popenoe 1924). (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Description

  • Solitary, or sparsely clustering palm, with several suckering offshoots at base. Stem to 30 m tall, without leaf sheaths to c. 40 - 50 cm diam.; trunk dull brown, marked with diamond-shaped leaf base scars c. 10 x 25 - 30 cm. Leaves straight, obliquely vertical in orientation, to 3 - 4 (5) m long; leaf base 15 - 20 cm wide; pseudopetiole 50 - 100 cm long; leaf sheath reddish-brown, to c. 45 cm long, fibrous; acanthophylls sparsely arranged, pointing in several directions, to 20 cm long; leaflets variously arranged in 1 - 3 planes of orientation, c. 50 - 130 on each side of rachis, stiff, c. 40 x 2 cm in length; lamina concolorous, glaucous, drying pale green. Staminate inflorescences erect; prophyll splitting 1 - 2 times between margins, yellow- green with reddish-brown tomentum when young, becoming brown and coriaceous, to 45 x 12 cm; peduncle to c. 50 cm long; rachillae to 30 cm long. Staminate flowers crowded along full length of rachillae; calyx a 3-lobed cupule with uneven margin, loosely surrounding the corolla; petals, 3 (rarely 4), creamy yellow-white, fleshy, each 7- 10 x 3 - 5 mm with apex rounded and minutely serrate; stamen c. 5 mm. Pistillate inflorescences initially erect, becoming pendulous with maturity; prophyll splitting between margins, yellow-green, c. 100 cm long; peduncle yellow-green, 60 - 150 cm, greatly elongating after fertilisation; rachillae c. 150 in number, yellow, to c. 40 cm long, elongating with fruit maturation. Pistillate flowers mostly in distal half of rachillae, yellow-white, with faintly sweet scent; calyx cupule c. 2 - 3 mm high; petals, 3 (rarely 4), c. 4 - 5 x 4 mm. Fruit very variable in shape and size, 4 - 7 x 2 - 3 cm, ripening a range of colours from yellow and green to orange, red, purplish- brown to black; mesocarp sweet, thick and fleshy or dry and thin. Seed variable in size and shape but generally elongate, 20 - 30 x 5 - 8 mm, with apices rounded or pointed; embryo lateral opposite raphe; endosperm homogeneous. (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Materials Examined

  • ALGERIA. 1888 (pist.), Christ s.n. (FI-B!). BAHRAIN Is. without precise locality, 21 Feb. 1926 (ster.), Fernandez 2863 (K!). EGYPT. Abusir, near El Merq, 21 March 1924 (stam.), Simpson 1826 (K!); Nile, (pist.), Hall s.n. (K!). ISRAEL. Jericho, 1 April 1913 (stam.), American Colony, Jerusalem 6985 (K!). LIBYA. Kufra oases, 23 Aug. 1963 (seedlings), Cambridge Expedition 18 (K!). MOROCCO. Between Tiznit and Agadir, 18 Dec. 1951 (pist.), Chevalier s.n. (P!); High Atlas, near Marrakech, 450 m alt., 26 June 1971 (pist.), Bocquet 11071 (BM!). PAKISTAN. N Baluchistan, (ster.), s.n. (CAL!). SAUDI ARABIA. Wadi Hebron, 1835 (pist.), Schimper 250 (FI-W!); NearJizan Dam, 12 Jan. 1980 (ster.), Chaudhary E421 (E!). SOCOTRA. Hagghiher Mts, Kishen, 12˚35'N, 50˚03'E, May 1967 (pist.), Smith & Lavranos s.n. (K!). SYRIA. Lake Tiberius, 1860, Hooker & Hanbury s.n. (K!). UNITED ARAB EMIRATES. Kalba oasis, 20 Feb. 1985 (stam.), Western 722 (E!). SPAIN. Murcia, April 1854 (stam., pist.), Diseglise 2314 (BM!); Barcelona, March 1913 (stam., pist.), Sennen 1807 (BM!). (Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae))A

Bibliography

    A. Barrow, S.C. 1998: A Monograph of Phoenix L. (Palmae: Coryphoideae)
    B. World Checklist of Arecaceae