I'm grateful for the quick answer to my former question. I've another plant (see the photos attached) that seems be a Cereus forbesii, but I've some doubts. Thanks for any tips. A. Urban.
Cereus peruvianus Hey A. Urban I'm looking at my Houseplant book, and what I see on you images is what is in my book. In my book the plant it is call Cereus peruvianus monstrosus ( Rock Cactus ) it says that the stem reaching 2-3ft in time and bearing 6 in. long flowers in summer. If someone else can let you know about this plant I would like to know too.
Cereus forbesii Otto ex Salm-Dyck is synonymous with C. validus Haw. The original identity of both C. forbesii and C. validus is uncertain, but the two names are currently applied to a distinctive and quite widespread Argentinian species. C. peruvianus misapplied, see C. uruguyanus Kiesling. Both C. validus and C. uruguyanus may eventually reach 6m (20') C. uruguyanus has 6 to 9 ribs, usually 8. The plant in question might be a C. 'Monstrosus'.
I have another plant that I could identify as C. peruvianus monstrosus and thei differ in so many aspects. See in www.cactusweb.us/monstrosus02.html is the same plant I have. The better hipotesis is that the plant that I want to identify is a C. hildmannianus ssp. uruguayanus. See in www.desert-tropicals.com/Plants/Cactaceae/Cereus_uruguayanus.html where is mentioned that "(...) often spinier than the type species." You can see a photo of C. hidmannianus ssp. uruguayanus like the mine in www.cactusweb.us/twistedcereus.html. I remember that I've see in a portuguese book about cactus that this cactus is original from Uruguay, but only a unique specimen lives today in their original habitat. Thank you for your answer. A. Urban.
Chris, you helped me a lot. See the former message I sent. An additional information is that I've seen a specimen of the C. hidmannianus ssp. uruguayanus in the same place I've bought the mine with about 2,30 meters. A. Urban.
