Figure 3 from: Gebauer R, Řepka R, Šmudla R, Mamoňová M, Ďurkovič J (2016) Anatomical and morphological spine variation in Gymnocalycium kieslingii subsp. castaneum (Cactaceae). PhytoKeys 69: 1-15. https://doi.org/10.3897/phytokeys.69.8847

Figure 3 - Typical radial arrangement of spines within an areole of Gymnocalycium kieslingii subsp. castaneum. All spines are straight or slightly curved to the body. The lowest spine is pointing downward. Scale bar = 5 mm.