We found our first specimens of Parodia mueller-melchersii (Backeberg) N. P. Taylor in November 2006, doing research at the northern area of Lunarejo Valley, near Tranqueras in the Department of Rivera (Uruguay), on Mario Padern’s property. At the time we were not sure of the accuracy of the attribution, as some of the small group of plants observed showed morphological characteristics rather distant from the original description by Backeberg (1936, 254, 415), a description that was basically incorporated, with minor modifications, by Anderson (2001, 547-548) and by Hunt et al. (2006, text: 221), as well as being distant from the photos used to illustrate the taxon in the literature (Hunt et al. 2006, Atlas: 312, pl. 312.3, 312.4). The characteristics of the Tranqueras specimens (photos 2-4) that differ the most from the description of P. mueller-melchersii are a very elongated body, instead of the almost spherical body that is reported, and almost completely dark red central awl spine, instead of pale yellow with red brown base and dark spots. The same particularities draw the plants closer to the descriptions of some taxa later considered conspecific with P. mueller-melchersii (Hunt et al. 2006, text: 310), ie Notocactus veenianus Van Vliet (1974, 53 (9): 171-173) and Notocactus winkleri Van Vliet (1975, 54 (7): 136-139); both with elongated bodies, respectively 20 and 24 cm, apex covered with dark red spines, and both found in the Department of Taquarembó Uruguay. Our doubt was whether the two taxa in question could not benefit from some form of autonomy from P. mueller-melchersii because of the diversity noticed; and as a result of the survey in the Department of Taquarembó, near the same named town, in the area between Valle Edén and Tambores, we found the answers we were looking for. In November 2008, looking at different populations of P. mueller-melchersii we found that the taxon, in its closest form to the one presented by the literature, is morphologically very similar to, almost not distinguished from, some forms of Parodia mammulosa (Lamaire) N. P. Taylor with which it may live in sympatry, differing from the latter by a greater number of ribs (21-24 vs. 13-21), not flattened central spines and thinner radial spines.  However, these elements cannot always be considered as distinguishing between the two. On the other hand, in some populations the plants are quite variable, so much so that they were taken for "new" taxa, as in the cases of the "discoveries" by Van Vliet. We therefore agree that N. veenianus and N. winkleri are just synonyms of P. mueller-melchersii, as forms of transitions or of different growth of the same taxon; however we believe that if this is true, the next descriptions submitted need to be more elastic and above all that the pictures need to document this variety. So, if P. mueller-melchersii can reach 20 cm or more in height (photos 2-3, 15-16) and have completely red central spines (photos 2-4, 24-25), or both the two characteristics (photos 2-3), although not consistent with, nor so close to, Backeberg’s description it must be taken into account. It speaks of an 8 cm high plant, with 6 cm diameter and with a light yellow central spine and dark extremities. (Quoted from Anceschi & Magli 2010, 26-28)

Parodia mueller-melchersii (Backeberg) N. P. Taylor represents one of the 62 accepted species in our synopsis of the genus Parodia Spegazzini s.l. (Cactaceae), published in Bradleya 36/2018, pages 70-161. For an update and more informations in our understanding of the taxon (see on pages 119-121, 154), the full text of the article is available here: A synopsis of the genus Parodia Spegazzini s.l. (Cactaceae). (PDF 4.5MB).

October 2018

Parodia mueller-melchersii (Backeberg) N. P. Taylor represents one of the external vicariants in the complex of the dominant Parodia mammulosa (Lamaire) N. P. Taylor.
We treated the dominant-vicariant relationship within Parodia s.l. in our article “Dominant species in Parodia Spegazzini s.l. Cactaceae” published in CactusWorld Vol. 38(4) Special Issue: 3-26 (December 2020). The full text is available here.

January 2021