ACACIA ALBIDA Delile.—Gawo. LEGUMINOSAE.
This is the largest of the Acacias in the north, and attains a height of over 60 feet with girths over 12 feet. It is particularly common in Sokoto, but even there is locally distributed, and gregarious clumps are commonly met with. It prefers dry, sandy soils. The form of the young and the old tree is very different. The former has a straight bole with acutely ascending branches forming a high, flat-topped crown very similar to that of Paradaniellia in shape. The bole may be clean for over 20 feet, but in young trees there are usually clusters of thorny twigs at no great height. As age increases the crown widens and the limbs get heavier and more spreading until the form is like that of Parkia. The bole is then quite clean and considerably thickened at the base, the roots spreading above ground and forming flanges, thick but of little height. Its distinguishing peculiarity is the habit of shedding its leaves at the approach of the rains and putting them forth at the first sign of the dry season, in September. It grows fast up to full height and then slowly.
The Bark is uniform dull grey. Long wide fissures and prominent ridges of hard bark ascend the bole and the bark appears as if it was stretched without being cast off. Light brown patches, quickly turning grey, are left by the falling scales. The slash is pale brown and fibrous.
The Thorns are in pairs, under ½ inch long and slightly recurved. They are pale brown with white bases. The young tree is armed all over, but as the tree ages the thorns leave the stem and finally the higher branches are free as if protection seemed to be unnecessary at a height.
The Wood.—The heartwood is a light, clean yellow. The sapwood is a dirty white. Frequently the whole wood is a dirty white or grey, but this is due to discolourations from mould and the wood should always be seasoned in dry air and not allowed to get wet. In transverse section the rings are indistinct and wide apart, the pores are small and evenly distributed, mostly in festoons with twin pores here and there, the soft tissue plainly seen as concentric lines with the hard tissue alternating. The rays are extremely fine, very regular and closely spaced and quite invisible to the naked eye. In vertical section there are faint bands of colour, with light reflecting flecks in tangential section. The wood is soft, very easy to work with all tools, seasons well if looked after, and finishes well under the plane. The weight is 35 lbs. a cubic foot.
The Leaves are bipinnate, 4 inches long with 6-7 pairs of pinnae bearing some 10-15 pairs of dusty, grey-green leaflets, covered with tiny hairs. The foliage in the mass appears bluish-green. It appears at the end of September and is susceptible to insect, caterpillar and locust.
The Flowers, from October to December, are in dense spikes 3-4 inches long, scented. The lower inch of the spike is flowerless. Several spikes are borne at the twig ends. Each flower has a 5-lobed cream-coloured calyx with pink centre, 40-50 stamens, and a short pistil with slightly clubbed stigma.
The Fruits are pods, at first green and sickle shaped, ripening to a bright orange and twisting into strange shapes. They are 4-6 inches long, 1 inch wide, concave on one side, convex on the other. They contain dark brown shiny seeds ⅜ inch long. The pods ripen in January and February and fall entire, rotting on the ground.
Uses.—Inferior canoes, of the stitched together type are made. The ripe pods are collected and fed to cattle, sheep and goats. The common brown kite nests frequently in its branches in March and April.
