This species was described by Bentham from the same area as Ixora venulosa, and said to be similar to that. It is characterized by medium-sized petiolate elliptic leaves, pedunculate cymose inflorescences, obtuse flower buds, and cream corollas with tubes 4.5-6.5 mm long and the lobes a little longer than the tube. The leaves on both surfaces are shiny with the fairly closely reticulated secondary, intersecondary, and tertiary venation raised. This species is characterized by most authors as distinctive in having numerous closely set secondary veins, but the secondary veins are similar in number and arrangement to those of most other eastern Brazilian Ixora species. The distinctive appearance of the leaves of Ixora venulosa is due to these well developed closely set intersecondary veins, with usually 3 or more intersecondary veins clearly evident between each pair of secondary veins.

Ixora brevifolia has been circumscribed rather broadly, in particular by the Brazil Catalogue, where various names of Mueller's were synonymized. This name there included Ixora syringiflora, which was however treated as a separate species by (Delprete, 2007) based mainly on size of the inflorescences and leaves. Also several new Ixora species have recently been separated from Ixora brevifolia, and contrasted in their protologues to Ixora brevifolia but not to any of Mueller's original closely related or segregate taxa. Recently separated species include Ixora pilosostyla of Bahia and Espírito Santo, with pubescent styles and stigmas, and Ixora aragauiensis of Tocantins, with a reduced habit.

Plants of Ixora from seasonal forests in northern Bolivia are morphologically indistinguishable from central and eastern Brazil, and are here included in Ixora brevifolia. These plants may be disjunct but the areas between these known populations is very poorly known botanically.

Ixora brevifolia is additionally similar to Ixora venulosa, and their separation probably deserves further evaluation. These two species were descrbed from the same region, and separated by Bentham mainly by generalized leaf size, the degree of development of the reticulated leaf venation, and the length of the corolla tubes to lobes. He noted that the corolla lobes are a little shorter than the tube in Ixora venulosa, and a little longer than the tube in Ixora brevifolia. However this ratio of corolla lobes to tubes appears to vary in some areas, such as among plants of Ixora venulosa in Paraná (pers. obs., herbarium specimens) and among plants of Ixora brevifolia in the northern end of its range (Delprete, 2010: 589-590). Jund-Menadçolli (2007) separated these species in her key by number of "secondary veins" in the leaves with the ranges overlapping, but described their corollas as distinct similarly to the proportions noted by Bentham.

The name Ixora brevifolia has been frequently mis-spelled as "breviflora"; but Ixora breviflora Hiern is a plant from Africa that is now treated as Ixora guineensis Benth. Two specimens imaged at K were annotated in Wernham's handwriting with the name "Ixora breviflora Benth." but that name is unpublished.