Fig. 6. Left, tubercles of A. fissuratus var. lloydii (Coahuila, Parras, WA.FitzMaurice). (photo: W.A. FitzMaurice), Right, Top. and Right, Bottom, tubercle details of two plants intermediate between var. fissuratus and var. lloydii (Coahuila, KM141 S of Cuatrocienegas, Valle El Hundido, W.A. FitzMaurice). (photo: W.A. FitzMaurice)