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.
Solitary or sparsely clustering palm, never thicket-forming, with massive erect trunk 40–50 cm. in diameter, ultimately to ± 20 m. tall, but rarely reaching more that 8 m. in East Africa. Trunk dull brown, conspicuously marked with leaf-sheath scars and short bases; leaf-bases ± 25–30 cm. wide and 10 cm. high. Crown of mature individuals with 50 or more green leaves. Leaf to 3 m. or more long with rather stiff rachis and petiole only slightly arcuate; true petiole to 20 cm. only, with coarse brown sacking-like sheath; apparent petiole 50-100 cm., armed with acanthophylls; acantho-phylls to 15 cm. long by 4 mm. wide, aligned in various directions; leaflets about 80 on each side of the rachis, stiff, moderately regular, sometimes slightly fanned, tending to point distally as opposed to being inserted at right-angles, dull glaucous green in colour, to 30 × 2 cm. Male inflorescence large; peduncle to 60 cm. or more; prophyll ± 45 cm. by 10 cm. wide, brown furfuraceous when young; rachillae numerous to 30 cm. or more, with staminate flowers in scattered groups or singly. Male flower somewhat asymmetrical, rather obtuse at the tip, not acuminate; calyx to 2 mm. long; petals cream, fleshy, to 8 mm. long, 3 mm. wide; pistillode minute. Female inflorescence as the ♂, but the peduncle greatly elongating after anthesis, pendulous; rachillae to 40 cm. long by 3 mm. wide. Pistillate flower globose, ± 5 mm. in diameter at anthesis; calyx ± 2 mm. long; petals rounded ± 4 mm. long by 4 mm. wide, imbricate; carpels ±2.5 mm. long, only the reflexed stigmas exposed at anthesis. Fruit very variable, 4–7 cm. long by 2–3 cm. wide, varying from yellow to orangey brown, to deep chestnut or almost black in colour, with mesocarp varying from thick, sweet and juicy to thin and dry. Seed similarly variable, ± 2.4 cm. long by 0.6–0.8 cm. wide, with conspicuous longitudinal furrow; embryo lateral.
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.
HAB. Waste ground and village margins; sea-level to ± 2500 m.
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.
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.
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).
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)].