The almost completely autogamous species Coffea arabica L. is polymorphic, twenty five varieties and four forms having already been described. The homozygous types for new genetic factors are considered new varieties, but recombinations of already known genes are not described as such. In 1938 a coffee plant was found at the Central Experiment Station coffee nursery, which showed abnormal leaves and irregular branching. As this variant appeared in a F2 population derived from a normal coffee plant, it is supposed to have originated by mutation. A study of the progeny of this mutant, obtained through artificial selfpollination, revealed that it is heterozygous for one pair of genes, which so far had not been encountered in C. arabica. Plants homozygous for this gene are described in the present paper as a new variety, anormalis. The branching habit of the anormalis variety is very abnormal, showing an excess of orthotropic branches arising at various nodes. The lateral branches are also abnormal. The leaves are extremely variable in shape and size ; sometimes they have two apices ; others are deeply incised often to the base of the petiole. The number of leaves at each node may vary from 1 to 4 ; the stipules, located between the insertion regions of the petioles, are large and irregularly shaped. The flowers show abnormalities in all their organs. The fruits are usually normal in shape and have a rather large disc. Abnormal seeds, of the "shell" (concha) type, frequently occur. A similar abnormal coffee plant was also found in a field planting in the Avaré county. It seems probable that it also arose through mutation and that it possesses the same gene which determines the characters of the anormalis variety found in Campinas.