The correct binomial for Rumph’s “Folium tinctorum”

In my “Notes on the Acanthaceae of Java” (in Verh. Kon. Ned. Akad. v. Wetensch., Afd. Natuurk. 2nd Sect. 45, 2: 29,1948) I discussed the three epithets that had been applied to Rumph’s “Folium tinctorum” after the latter had been transferred to the genus Peristrophe, which, as is well known, was based on this species. Nees, the author of the genus, has used the name P. tinctoria, because he regarded Justicia tinctoria Roxb. as the oldest binomial that had been applied to it. This was contested both by Merrill and by Hochreutiner. Merrill was of opinion that Justicia bivalvis L (1759) was its oldest name, but as I pointed out l.c. this binomial must be regarded as a “nomen confusum”; the description indicates a Dicliptera species, whereas the plate in the “Hortus Malabaricus” and the specimina in Burman’s herbarium to which Linné referred, represent respectively Adhatoda vasica Nees and indeed “Folium tinctorum”. Hochreutiner, on the other hand, thought, that Justicia purpurea L (1753) was identical with Rumph’s plant, but this too proved to be a mistake. J. purpurea belongs, as R. Brown already had recognized, to Hypoëstes. As the binomials proposed by Merrill and Hochreutiner therefore had to be rejected, I accepted l.c. Peristrophe tinctoria (Roxb.) Nees as the correct name. This, however, is also erroneous, for Justicia tinctoria Roxb. itself is an illegitimate name, for which already long ago a legitimate one had been substituted. J. tinctoria Roxb. (1820) is a later homonym of J. tinctoria Lour. (1790). This was recognized already by Schultes (Mantissa 1: 140, 1822), who replaced Roxburgh’s epithet by roxburghiana quoting “ J. tinctoria Roxb., Fl. Ind. ed. Car. et Wall. I p. 124, n. 13 et hoc teste: Folium tinctorum Rumph. Amb. VI 51. t. XXII. f.l” adding “nomen mutandum erat ob tinctoriam antiquissimam Lour”. As Loureiro expressly stated that the plant described by him as J. tinctoria was not the same as “Folium tinctorum” of Rumph, it is clear that J. roxburghiana Schult. must be accepted as the oldest legitimate binomial for the latter. The correct name therefore becomes Peristrophe roxburghiana (Schult.) Brem. n. comb.