Aristolochia trilobata is one of the most well-known species yet very often misidentified and mixed up with the similar A. macroura.

Both species share similar habitats in central and southern America.

As genetic investigations are missing the floral characteristics are the only features to be used to tell them apart more or less easy.

 

Usually A. trilobata possesses a single crest in the female stage of the flower whereas A. macroura is double-crested and generally more compact. However, both species tend to vary at least to a little extent so it would be particularly interesting to see whether these and a few other characteristics are stable on a genetic level as well.

 

A. trilobata flowers comparatively are much more fragile and of whitish ground colour. Utricle and tube are both elongated and scattered with brown blotches. The upper/front part of the flower is the most different characteristic in my opinion, displaying a very narrow limb base and elevating the limb with brownish stripes which bears a shorter and thinner appendix compared to A. macroura.