ABSTRACT
The taxonomy of Aloaceae is discussed at the family, genus and species levels. A key is provided to the seven genera accepted in the present chapter.
There is no doubt that ancient peoples classified plants. However, the folk-taxonomic groupings that they used were much simpler and more robust than those used today (Stace, 1980). Typical mental abstractions (categories) into which plants were placed were whether they were useful (e.g. as sources of food or building materials), poisonous, or could be worshipped. The species of Aloe L., particularly the widely known and used A. vera (L.) Burm.f., would no doubt have been included in the first-mentioned of these categories. The remarkable healing powers of the leaf juices of various species of Aloe have been known for very long and were used before and in biblical times; one of their uses was as an ingredient in embalming ointments (Bible, New Testament: John 19: 39; Admiraal, 1984; Smith, 1993). However, as with all plants, the formal taxonomy of species of Aloe and their relatives dates back only to 1753 when Linnaeus proposed his sexual system of plant classification, based primarily on the number of stamens and pistils in a flower. Since species of Aloe have six stamens and a single pistil, they fitted comfortably into the Hexandria Monogynia of Linnaeus (1753). The artificiality of the Linnean System was widely realised and between 1753 and the early 1800s various attempts at a Natural Classification of plants, thus classifying them to reflect overall similarities, were made. The aloes and their relatives were also subjected to these proposals and they saw a number of familial reshufflements over the past 250-odd years. In addition, alooid genus delimitation and the circumscription of species have also been the subject of taxonomic argument. This chapter provides a synoptic overview of the taxonomy of, especially, higher-category alooid taxa. The currently accepted genera are also briefly discussed and a key to facilitate their identification is provided.
