Synonyms

Monvillea saxicola, Praecereus saxicola, Monvillea chacoana, Monvillea parapetiensis, Cereus ritteri ssp. parapetiensis, Monvillea rhodoleucantha, Cereus rhodoleucanthus, Cereus euchlorus ssp. rhodoleucanthus, Cereus ritteri

Distribution

Argentina, Brazil, Paraguay

Conservation status

(3)   Least Concern, LC

Comments

Whilst previewing the implications of his work on the tribe Cereeae in a presentation at the IOS Congress in 2006 (Machado et al. 2006) Marlon Machado reported that the results of molecular analysis in progress will affect various genera. Among the genera involved, there is the possible inclusion of Praecereus Buxbaum in Cereus P. Miller. We completely agree with the data. In fact, not even in the course of our studies in habitat, not even in the comparison of the data with the literature, could we find qualitative and quantitative characters that might highlight a possible distinction of Praecereus. By doing a brief review of the recent history of the genus, we can see how weak the distinctions made for the separation are. In 1986, the International Cactaceae Systematics Group initially included Praecereus in Monvillea Britton & Rose, keeping the latter separate from Cereus (Hunt & Taylor, 1986, 4: 70). In 1990 The ICSG included Monvillea in Cereus (Hunt & Taylor, 1990, 8: 90). The evidence that led Anderson (2001, 589) to differentiate Praecereus is based on the studies of Taylor and Zappi ((1989)): a cladistic analysis of the tribe Cereeae, where Praecereus is considered to be a subgenus of Cereus. And on those of Taylor (1992, 1997), a study for the definition of Cereus, the first on the proposal of the new combination of Cereus euchlorus F. A. C. Weber (and related subspecies), and Cereus saxicola Morong in Praecereus, the second. This evidence, based on Backeberg’s observations of the members in its sub-genus Hummelia of Monvillea (which are taxa that have been in the most part assimilated in Praecereus by Buxbaum), consists of flowers with stout, curved floral tubes and oblong ovaries. Anderson also admits that despite the investigations of Taylor and Zappi, the boundaries between these genera willl remain fuzzy. Assuming that in classification any kind of distinction based on a single character is in itself artificial, we want to point out that the latest molecular analysis (Nyffeler y Eggli 2010, 15; Schlumpberger & Renner, 2012, 1347-1348) shows that the characters of the flowers and the different pollination syndromes are not indicators of the proximity or remoteness of two evolutionary lines. Indeed, Praecereus is indistinguishable from the other species of Cereus with slender stems, previously attributed to the genus Monvillea. For these reasons, we believe that Praecereus must be put together with Cereus. (Quoted from: Anceschi & Magli 2013b, 44)

Genus

Cereus

Other species

aethiops
bradei
crassisepalus
euchlorus
fernambucensis
forbesii
hildmannianus
jamacaru
laniflorus
lanosus
minensis
phatnospermus
saxicola
spegazzinii
stenogonus