The botany of the Guayana Highland--Part XI. Convolvulaceae

The family Convolvulaceae is usually considered most abundant in the lowland regions of the tropics. Perhaps this concept is true for the numbers of individuals, but it is beginning to appear that the greatest species diversity is in the plateau regions such as the Guayana Highland, the margins of the Andes, and the Brazilian Shield. Until recently there were few collections from any of these areas, particularly the Guayana Highland. In fact, except for the now outdated treatments of the family by van Ooststroom and Pittier et al, the more recent study of the tribe Erycibeae, and an unpublished study of the family for the "Flora de Venezuela" (Austin, mss.), little has been known of the group in the entire Guayana region.We recently examined the collections made by Dr. Bassett Maguire and his colleagues over the past few years and, to date, have found fourteen genera and a total of forty-four species of Convolvulaceae in the Guayana Highland. A few others are known from the Crystalline Shield and may be found within the Highland in the future. Several of these species were unexpected, and one is new to science.