Could this be...

[Colin Walker]

Hi Devrim,

Yep, the spelling is correct with three 'i', so it's Brasiliopuntia.

[Colin Walker]

Hi Ian,

I'm following what's used in The New Cactus Lexicon (NCL) because this is the latest treatment for the whole Cactaceae.

The splitting up of Opuntia into 16 separate genera is based on molecular studies, in which DNA was sequenced from a range of species, the sequences were compared and a phylogenetic or evolutionary tree was constructed, which aimed to indicate how plants are related. So this is more than personal opinion, it is based on hard data.

Opuntia brasiliensis was found to be sufficiently distinct as to merit its own genus, hence Brasiliopuntia brasiliensis. This happens to be one of the older generic names, dating back to Berger in 1926. Some names are even older than this: e.g. Nopalea is a Salm-Dyck name from 1850. Of course Opuntia is the oldest name (1754) for this group (apart from Cactus itself, that's a year older but no longer used).

You could accept a single genus Opuntia if you so wished, but this doesn't give us any clues as to the relationships of a very large number (hundreds) of species.

Reference for all of this is:

David Hunt & Nigel Taylor. Studies in the Opuntioideae. Succulent Plant Research Vol. 6, David Hunt Publications, Milborne Port, Dorset, 2002.

[Victoria]

I have always bee intrigued why Cactus is not used, can you enlighten me Colin?

[iann]

The genus name Cactus has been formally rejected by the rules of the ICBN and cannot now be used. I believe that this was done in the context of conserving the name Mammillaria. Once multiple genera had become accepted within the cactus family it was felt that calling just one of them Cactus would be confusing.

Almost by definition, all genera other than Cactus would be newer since Linnaeus named Cactus at the accepted start of binomial taxonomy. However, several other genus names had been in widespread use for decades before 1753, including Opuntia.

[DaveW]

Linne's generic name Cactus contained a mixture of too many unrelated plants Victoria, so they decided to conserve the later names Mammillaria and Melocactus instead of it:-

[attachment 13637 CACTUS.jpg]

(nomen conservandum = conserved name)

DaveW