The savannah species are, then, well equipped to withstand fire, drought, insects, wounds, storms, and damage by man and it can be imagined how readily they will supplant better types, since the harder the conditions the better adapted are the trees to meet them. The wide distribution of most species renders them more aggressive, and an individual species that will grow into a fine tree under the best conditions can still grow under the worst, though it may differ in form and feature so as to be hardly recognisable as the same species. If, as it is supposed, savannah forests are depreciating of their own accord, some factor other than climate, which has not been demonstrated by records, must be at work. It is sufficient to point to the increase and spread of the population from the towns to the forests to find a reason for the displacement of good forest by lower grades. Shifting cultivation encourages a worse type each time it is practiced and late fires are very destructive. For valuable assistance given in identifying the trees and shrubs in this volume, the author is indebted to Dr. A. W. Hill, Director of the Royal Botanic Gardens, Kew, and Mr. J. Hutchinson of the Herbarium. To Dr. J. M. Dalziel he is indebted for the “Hausa Botanical Vocabulary,” a valuable short-cut to further research. Other books referred to are the “Flora of Tropical Africa” and Kew Bulletin, Additional Series IX., neither of which has been used other than for purposes of classification, it being the author’s aim to describe and illustrate the material as it appears to be, and not only as it actually is from the scientific point of view, avoiding botanical terms except where they have no alternatives. H. V. L. _March_, 1925. =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.