Tournefortiopsis crispiflora is the most commonly collected species of this genus and is found throughout the range of this genus. It is locally often common, but also commonly collected in part because it is frequent in secondary vegetation, often in flower, and usually a short enough tree to be easy to collect from the ground.
Tournefortiopsis crispiflora shows a wide range of morphological variation, with varrious distinctive forms that are, however, linked by intermediate forms and variation in pubescence, leaf size and shape, and flower size with variation in these characters, however, not well correlated with any other characters. All authors have regarded Trouneofortiopsis crispiflora as comprising a morphologically variable complex of forms and geographic populations, and no authors have agreed on a taxonomic view of these plants. The main feature that seems to be distinctive among the morphological variants is pubescence form, which is not usually a character diagnostic of lineages in Rubiaceae.
Four subspecies are separated here generally following the perspective of Taylor and Lorence (2001), who noted that several regional, morphologically distinctive populations can be identified and largely but incompletely separated. Pubescence details help characterize these subspecies, in correlation with geographic distribution, but some other morphological features show generally similar ranges of variation within each subspecies. The discernible morphological patterns appear to indicate some systematic differentiation within this species, so these forms are recognized taxonomically. These infraspecific groups are separated as subspecies because their morphological features correspond generally with geographic distribution. However, these subspecies are connected by morphological intermediates and are not completely distinct geographically, at least as to their general distributions; whether any of these are sympatric locally has not been studied.
Tournefortiopsis crispiflora is similar to Tournefortiopsis dependens, and these have been variously combined and confused and their separation needs further study. Tournefortiopsis dependens can be recognized by its inflorescences that are usually widely spreading to pendulous, flowers that are often pedicellate, generally 5-lobed calyx and corolla, and corolla tubes that are usually deep pink to purple or red externally.