This fairly casual merger combined it with Lobivia and several other genera of cacti. [Additional comments]
      In the process was created a huge taxonomic and nomenclatural nightmare that no one has been willing to attempt to resolve.
      This is hardly a surprise as a disturbing number of what are now accepted as Echinopsis species completely lack a Latin diagnosis and/or meaningful floristic descriptions.
      Cereus (Echinopsis) lageniformis for instance is clearly an inadequate description discussing a 12 inch tall *sterile* clone said to have originated from Peru.
      It's description in Hamburger Garten is lacking a Latin diagnostic (not even one comprised of a meager line or two), any description of the flowers and also omits the mention of an herbarium voucher.
      What description it does have is phrased as if it was written for a local amateur garden club's newsletter.

      It can even be quite justifiably argued that the BASIC morphological descriptions published for many of the Trichs aren't even representative characteristics for more than a portion of the known living material. Sometimes these plants have been described on the basis of solitary specimens existing in a Botanical Garden far from home or a sterile specimen encountered in the field (with a few branches lopped off for herbarium study).
      Consider, for instance, T. pachanoi's described girth, color, rib numbers, spine numbers, spine lengths, or spine color.
      In every case, specimens can be found which violate the 'norm' yet are correctly identified. This is true within large plantings of seeds, large enough wild populations or even as odd branches on otherwise normal plants.
      As example; (if modified), the described (5-)6-8 ribs does fit the majority of T. pachanoi on the planet but the reality (in horticulture and in the wild) is actually a range more like 4 to 14 ribs and we would balk at being committed to either end of that as necessarily being some sort of an absolute.
      Normally, if such a large revision was attempted it would be presented accompanied by a monograph on the genus and creation of a taxonomic key. For this revision, what was presented was a simple listing of name changes.
      The presence of "describer" names on the "new" names generally means NOTHING more than the fact that these people simply renamed the plants.

Three things are easily forgotten in the rush towards uniformly compliant acceptance of the renaming of the genus:
    1) In discussing their proposed revision, Friedrich & Glaetzle commented on the need for creation of subgenera as the sweeping revision had generated such an unwieldy taxonomic morass due to how many former genera were being lumped together. They ducked the bullet and left this monumental chore for some future worker. (Ha! Ha!) Ideally that would be someone with no life, deep pockets and a high index of frustation tolerance.
    2) A decent number of the Trichocereus species have NEVER had anything approaching a meaningful description written for them and any thought of creating a workable taxonomic key out of the published descriptions (or taxonomic keys) is deluded daydreaming at best.
    3) Due to their largely self-sterile nature and the ready ease of hybridization, the impact of the widespread, deliberate and often intensive plantings and transplantings of Trichocereus pachanoi & other related species throughout the Andes (across several countries and over the course of at least a few millenia) is underappreciated by most observers.
      What are currently perceived of, in a number of cases, as species and subspecies, often with a host of known "intermediates", are most likely something more akin to grex.
      For those unfamiliar with the term "grex", it means that a nest of hybrids have resulted from the repeated crossing and backcrossing of relatively few species to the point where visually distinct morphological peaks now appear to exist within what are in reality extremely closely related strains. (Think of the wealth of Brassicas developed/selected for by humans for food use as a well known example of grex.)
      In essence this hybrid component makes these plants of little to no interest to MOST taxonomists so the (sub)genus (as represented in horticulture and probably also in nature) is effectively no longer of anything but horticultural & sometimes ethnopharmacological interest.