Hyphaene thebaica (L.) Mart., Hist. Nat. Palm. 3: 226 (1838); Fl. W. Trop. Afr., ed. 2 3(1): 169 (1968); Palm. Afr. 28 (1995); Fl. Ethiopia & Eritrea 6: 522 (1997); Fl. Egypt (Boulos) 3: 104 (2002); Fl. anal. Bénin: 58 (2006); Boissiera 55: 33 (2012). – Icon.: Palm. Afr. 151, 152 (1995); Palms 52: 23-27 (2008).
Synonyms: Chamaeriphes crinita (Gaertn.) Kuntze; C. thebaica (L.) Kuntze; Corypha thebaica L.; Cucifera thebaica (L.) Delile; Douma thebaica (L.) Poir.; H. baikieana Furtado; H. crinita Gaertn.; H. cuciphera Pers.; H. dahomeensis Becc.; H. dankaliensis Becc.; H. nodularia Becc.; H. occidentalis Becc.; H. santoana Furtado; H. sinaitica Furtado; H. togoensis Dammer ex Becc.; H. tuleyana Furtado; Palma thebaica (L.) Jacq.
Palm solitary, rarely with basal suckers, tall, armed, pleonanthic, dioecious; stem (5-) 8-12 m in height and 20-40 cm in diameter, branched by dichotomies up to 4 times (Fig. 1), with the first one appearing 2.5-3 m above ground, producing up to 16 leaf crowns; the stem often covered with old leaf sheaths which fall off in aged individuals, grey, leaving conspicuous, 1-3 cm thick ring scars when young, then the scars becoming closer in older individuals.
Leaves (8-)10-18 (-20) per crown, costapalmate, spirally arranged, dark green to bluish; leaf sheath 24-30 cm long, 16-20 cm wide, grey-brown, with a triangular cleft at the base, often remaining below the leaf crown or throughout the length of the stem in young individuals, margins fibrous, armed from the mid-length with robust, triangular, upward pointing black spines; petiole (0.7-) 1.5-2 m long, (5-) 7-10 cm wide at the base and 3-4 cm at mid-length, green-grey to black, at the base adaxially channelled and abaxially rounded, towards the apex dorso-ventrally compressed in cross-section, margins armed with robust, triangular, reflexed or upward pointing black spines, up to 2 cm long and 0.8-1 cm wide at the base, displaying different shapes; hastula 1.5- 6 cm long, green, with slightly black margins; costa (30-) 50-60 cm long and 1.5-2.2 cm in width, light green, smooth, conspicuously recurved, triangular in cross-section; leaf blade 1-2 m long, showing small brown dots becoming darker when the leaf dries, divided at 1/3 of its length into 50-60 regular segments, main veins prominent on the abaxial side, basal segments 35-50 cm long and 1.5- 2.5 cm wide, medial segments 50-80 cm long and 2.5- 4.5 cm wide, apical segments up to 35-50 cm long and 1.5--4.5 cm wide, single-folded, with a slightly bifid apex up to 4-7 cm long, presence of interfold filaments between segments of up to 60 cm long, a brown, light and smooth indumentum present at the base of the leaf blade and encompassing the mid veins, especially on young leaves, and becoming caduceus on aged leaves.
Inflorescences unisexual, interfoliar, pistillate and staminate inflorescences similar, both branching to 2 orders; staminate inflorescence 1-branched, 1.2-2 m long, digitate, erect at juvenile stage and becoming pendent at anthesis; peduncle 30-50 cm long; prophyll tubular, eventually appearing dorso-ventrally compressed, opening apically as a lanceolate projection; peduncular bracts up to 16, basal bracts 28-30 cm long and 4-5 cm wide, medial bracts 12-15 cm long and 3-4 cm wide, apical bracts 6-10 cm long and 1-2 cm wide; rachis 9-15, 30 cm long; rachillae catkin-like, 18-22 (-25) cm long and 1-1.5 cm in cross-section, arranged in cluster of (2-) 4-5 rachillae; rachillae bracts 7-8 mm long and 2-3 mm wide, spirally arranged, striate, connate laterally and partially adnate to the rachilla, subtending pits containing 3 flowers arranged in a cincinnus; pistillate inflorescence, (0.4) 1-15 m long, peduncle 20-45 cm long, 1-1,5 cm in diameter, prophyll 20-25 cm long, apically opening with two longitudinal slits, coriaceous, brown, with a spongy indumentum towards the apex, peduncular bracts 3-5, smooth, similar to the prophyll, rachis 40-60 cm long, rachillae 6-8, 15-22 cm long, sterile part of 10-15 cm, 1-1,5 cm in diameter, solitary, rarely by pairs; rachillae bracts as resembling the ones of the male inflorescence, densely hairy, each pit containing a single flower, clearly larger than the male flower.
Flowers unisexual, 3-merous. Staminate flowers borne in a cincinnus of 3 flowers, one flower emerging at a time, subtended by a minute, membranous, green bracteole; calyx basally tubular, apically with 3 acute, elongated lobes; corolla with a stalk-like base, valvate, lobes 3, ovate, hooded, striate; stamens 6, connate at the base to the corolla, filaments with a swollen base, anthers medifixed, versatile, latrorse to introrse; pistillode 3-lobed, minute. Pistillate flowers larger than staminate, borne solitary in each pit, subtended by a membranous bracteole, supported by a short, thick, densely hairy pedicel; sepals 3, distinct, triangular-rounded, imbricate, striate; petals 3, similar to the sepals but more flexible; staminodes 6, fused in an epipetalous ring, sagittated, flattened, anthers undifferentiated; gynoecium globose, 3-carpellate, 3-ovulated but only reaching maturity.
Fruits 1-seeded (Fig.2), (4-) 5-6 cm long, 4-5 cm in wide, highly variable in shape and size (shouldered, asymmetrical, obovoid, rarely ovoid, usually pear-shaped), borne on a 6-8 mm long pedicel, basal stigmatic remains; epicarp ranging from orange, red to brown or dark-brown in ripe fruits, smooth, shiny, waxy, often presence of small dots; mesocarp conspicuously fibrous, up to 8 mm thick, sweet; endocarp well developed. Seeds as diversely shaped as the fruits, basally attached, endosperm white, with a coconut flavour when young, with a central hollow cavity when ripe; germination remote-tubular, cotyledonary petiole buried up to 80 cm underground; eophyll linear-lanceolate, plicate.
This is a palm of arid, desert climates, associated with the heavy soils of drainage lines and alluvial flats with high water tables.
The distribution of H. thebaica is rather complex due to the fact that the species is economically important and has traditionally been planted by human populations. It has been reported for the Sahel region (Burkina Faso, Mali, and Niger) and also in tropical West African countries (Côte d’Ivoire, Ghana and Senegal). This palm is also present in Cameroon, Somalia and Ethiopia (Tuley, 1995; Arbonier, 2009, Hedberg, et al., 2009); its presence in Angola needs to be confirmed (Baker, 2008).The species has been also reported in Madagascar (Dransfield and Beentje (1995) and in the Red Sea region, and the coasts of the Gulf of Eilat, Arabia (Dransfield et al., 2008) (Fig. 3).
Possible hybridization of this species with other taxa of Hyphaene has been reported by several authors and observed by us in the Botanical Garden of the University of Accra (Ghana).
In some West African countries (e.g. Ghana, Nigeria) the petiole and the leaf blade are used for the elaboration of baskets hats and fans. The stems, in particular those from male individuals, are sold as timber due to its recognized resistance to insects. The fruits are known to be occasionally eaten. A detailed description on the leaf collecting practices in this species was carried out by Kahn and Luxereau (2008). For a comprehensive description of the uses of this palm in West tropical Africa see Burkill (1997).
Fig. 1.Typical growth habit of Hyphaene thebaica in Western Djibouti
Fig. 2. In Hyphaene thebaica usually many infructescences are present on the same individual, giving a very informative picture on their development. The seed of this palm cultivated in the Montgomery Botanical Center (Miami, USA) was collected in the West African country of Burkina Faso.
Fig. 3. Distribution of Hyphaene thebaica (based on Stauffer et al., 2014)