Borassus akeassii

Family: Arecaceae    Palm Tree

Common Name: Ake Assi's Palmyra Palm

Scientific Synonymy:
Borassus aethiopum var. domesticus, Borassus flabellifer,

Cold Hardiness Zone: 10a     View the UK and US zone maps

Borassus akeassii Information

A solitary, large, drought tolerant, moderately fast growing, dioecious palm. Not known in cultivation and scarce in the wild. It has a rough, light-grey trunk, 15 m. (49 ft.) tall, 80 cm. (32 inch) diameter with no obvious leaf scars, and huge partially segmented, palmate (fan) leaves, 1.5 m. (5 ft.) long, 1.5 m. (5 ft.) wide, green above and beneath.

Stem almost always ventricose (swollen), often marked by numerous irregular scars caused by tapping. The species differs from B. aethiopum and B. flabellifer by the fruit being a green colour not yellow or black, and by the fruit apex being pointed not flat. Also having glaucous leaves. A particularly distinctive feature of this species is the pattern of veins on the leaves. When the leaves of B. aethiopum and B. flabellifer are dried, they have a smooth surface. This is as a result of the close spacing of the commissural veins (8-18 veins per cm). In B. akeassii, the veins are more widely spaced (5-7 per cm) and so provide less support to the leaf, which collapses into the rectangular spaces (lacunae) formed from surrounding veins. The result is that the dried leaf of B. akeassii has a rough surface with easily discernible puckering.

Borassus akeassii can tolerate close to freezing conditions. But low temperatures are best avoided, it will not tolerate any duration of dormancy and anything other than the briefest of cold snaps will surely kill a young plant. It naturally occurs in dry, arid, sun exposed, grassland locations, and should be planted to maximise Summer heat & sunshine exposure. Its roots will travel down to find water. Under cold conditions we recommend you keep this palm as dry as possible, which will usually mean constructing a glass or plastic roof over the plant to keep rain off, and supplemental heat provided over duration. Any cover placed over this palm during times of rain or during cold nights must be removed or vented during hours of sunshine or the plant could be severely heat stressed.

Identification

Stem to 15 m tall, almost always ventricose, to 80 cm diam.; stem often marked by numerous irregular scars caused by tapping. Leaves glaucous, 8-22 in the crown; petiole and sheath 90-160 cm long, 3.0-7.4 cm wide at midpoint, green, margins with small serrate black teeth, 0.2-0.6 cm long (immature leaves), or teeth largely absent (mature leaves); adaxial hastula conspicuous, to 2.4 cm, abaxial hastula rudimentary; lamina rather flat, radius to 160 cm maximum; leaflets 45-82, 2.8-7.3 cm wide, leaf divided to 60-99 cm. Male inflorescences branched to two orders, branches terminating in 1-3 catkin-like rachillae; rachillae green-brown, 23-36 x 2.3-2.5 cm; rachilla bracts forming pits that contain a cincinnus of 5-10 male flowers. Female inflorescences spicate or branched to one order; rachis ± 80 cm long, flower-bearing portion 24-39 cm long with ± 23 flowers arranged spirally. Male flowers 0.4-0.6 cm long, exerted from the pits individually or in groups of 3-5. Female flowers 3.5 x 3 cm. Fruits ± 15 x ± 12 cm diameter, ovoid with a somewhat pointed apex, fragrant and yellowish green at maturity, produced inside persistent perianth segments; pyrenes 1-3 per fruit, 6.8-9.3 x 5.4-7.5 cm.

General Information

A recently described species from West and Central Africa, in savannas with a lack of forest cover, and with 800-1300 mm annual rainfall. In Burkina Faso, most populations are semi-managed for wine production. While this species is probably more widespread, collections exist from only three countries: Burkina Faso, Senegal and the Democratic Republic of Congo.

Distribution

Native to: Burkina Faso, Congo, Senegal