Strictly typical C. haematocephala has relatively small (to about 2-4.5 x 0.7-1.2 cm), facially glabrous leaflets; it is commonly cultivated in Asia and is most closely approached, but not precisely matched, by R. S. Williams s.n. from the río Kaka near Isapuri (NY) and (ex char.) the holotypus of C. novaesii. Calliandra inaequilatera, the form most frequently grown in North America, differs to random degrees in facially pubescent leaflets mostly reaching 5-7.5 x 1-2.8 cm. In occasional leaves of this form one of a pair of pinnae may have 5-7 pairs of leaflets whereas the other has only four pairs. In C. fulgens, which may have arisen in cultivation, the leaflets are 3-4 pairs in all pinnae. A form cultivated in the Caroline Islands (Salsedo 119, NY) has the leaf-formula of C. fulgens but broader leaflets.

The ultimate provenance of the plants grown at Calcutta and in Java from which Hasskarl described C. haematocephala is unknown. Nevling and Elias, having established the taxonomic equivalence of C. haematocephala and C. inaequilatera, assumed that the former must have been introduced from the region of Guanaí in Bolivia, either by Hasskarl himself or by H. A. Weddell, both of whom are known to have traveled in the region between 1842 and 1853, in search of Cinchona. According to one hypothesis, plants were collected by Hasskarl himself, perhaps described by him on board ship between Peru and Java, and attributed to the Calcutta garden in order to conceal his role in smuggling living Cinchona out of Bolivia. Alternatively, it was Weddell who obtained seeds of the Calliandra, which passed to Calcutta either through Paris or London. There is, however, only circumstantial evidence in favor of either hypothesis and none to favor one over the other. It is worth noting that Hasskarl described in the same paper (Retzia 1: 214. 1855) a Calliandra sancti-pauli, likewise grown at Bogor, this said to have originated in São Paulo (see synonymy of C. foliolosa, p. 000) and to have come to Java by way of Utrecht. Several channels of communication between Bogor and Europe were open, and in absence of positive evidence the route taken by Calliandra haematocephala is unknowable.