hookahhead said:

His downfall?  He believed that cacti started in central america and radiated north and south, in different lineages.  He adamantly held onto this belief despite the compounding evidence against it.  Not wanting to admit his folly, he made gross over-generalizations just to make it fit HIS model.  Now, over 60 years later molecular phylogenitics prove he was absolutely, without a doubt WRONG.

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Yes they spread from SA up.

• Molecular evidence currently suggests that there are two primary clades of columnar cacti that arose from the South American ancestral populations, each having inferred common ancestries. 
  
• The first clade consists of three former tribes, Browningieae, Cereeae, and Trichocereeae, which all share a unique 300 bp deletion in cpDNA and strongly suggests a close ancestor.
  
• Because of the limited data for molecular phylogenetic resolution, this group has been generically named the “BCT” clade until further relations are determined.
  
• Interestingly, Buxbaum (1958) originally proposed that these groups are related to one another and constituted a single major radiation in South American cacti.
  
• Arakaki et. al. 2011 indicates that Trichocereinae has a relatively recent evolutionarily origin, about 7.5-6.5 Mya, and that the genetic divergence between members is far lower than the difference shown by morphological and floral characters. 
  
• Nyffeler & Eggli (2010), also point out that within the sub-tribe Trichocereinae, the most difficult group to interpret is the macro-genus Echinopsis.  With most sources agreeing that despite being polyphyletic, all taxa within tribe Echinopsis are intimately related
  
  

It's in the powerpoint


And this is from the paper...

Quote:

In spite of all the confusion, Gibson and Nobel (1986) published a textbook
with chapters about nearly all aspects of the cactus family, including morphology, anatomy, physiology, chemistry, and geography. Two chapters are devoted to “Phylogeny and Speciation” and “Evolutionary relationships”, which includes a comprehensive synthesis of cactus phylogeny and evolution, summarizing the published literature and their own studies. Their main conclusions about the phylogeny of Cactaceae can be summarized as follows:
• The Cactaceae are members of the order Caryophyllales.
• The closest relative of the Cactaceae is the family Portulacaceae.
• The Cactaceae has its geographic origin in northern South America.
• The Opuntioideae did not start their evolution in the West Indies.
• Within the Cactoideae, the tribe Leptocereeae possesses the most primitive characters.
• The poorly defined tribe Hylocereeae includes terrestrial and epiphytic cacti; the latter evolved from terrestrial forms.

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hookahhead said:

Kindling!  Out with the old and in with the New age.


http://www.amazon.com/The-New-Cactus-Lexicon-Illustrations/dp/0953813495/ref=sr_1_2?ie=UTF8&qid=1389227400&sr=8-2&keywords=cactus+lexicon

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This was the gift I gave myself this christmas.
Not so kind(le), though: it's meant to be taken easily to the greenhouse but, man, is it heavy...

psi said:

Can you expand on which aspects of this are now considered to be wrong? Did they originate somewhere other than Central America?

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Quote:

In 1949, as part of his reworking of the entire Cactacea family, he cleaved the Trichocereus genus in two.  This revision split the species by their floral development morphology.

Species with white petaled flowers that open at night would remain within Trichocereus

While those with red, orange, or yellow colored and day-opening flowers would be transferred into a new genus Helianthocereus.

• Arakaki et. al. 2011 indicates that Trichocereinae has a relatively recent evolutionarily origin, about 7.5-6.5 Mya, and that the genetic divergence between members is far lower than the difference shown by morphological and floral characters.
  

 

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