This Brazilian columnar cactus was described in the German journal Kakteen und andere Sukkulenten 58 (7): 183-188 (2007). At the time of its description, fruit and seed were not available. Therefore, its affinities could not be completely determined. However, it was suggested that it might be closest to the more widely distributed P. pachycladus of northeastern Brazil. Indeed, some botanists now consider P. hermii to be a synonym of P. pachycladus. However, further study (G. Olsthoorn, KuaS 69(10) 2018) has confirmed the distinctness of this species. P. hermii has stems with 8 - 10 ribs within the range for P. pachycladus subsp. pachycladus but, unlike that subspecies, lacks long central spines, instead having short pectinate spines mostly concealed in wool lining the ribs. Our seedlings still have slightly spinier areoles presumably until they grow to a less vulnerable size. From seed collected at the type locality, N of Buritis, along a tributary of the Rio Urucuia, Minas Gerais, Brazil. HBG 136036, $12
Published in the Cactus and Succulent Journal, Vol. 97 (2), Summer 2025