Thanks Paul,
I'll see if I can get a copy of that article and see what he has to say. I've always fought the concept of losing the name D. longissimum, and it's interesting to see that Bogler apparently has changed his mind somewhat.
As I recall, he indicated that the "type" specimen of D. longissimum was from an unspecified locality while the "type" specimen of D. quadrangulatum came from near Tula in Tamaulipas, and Bogler decided to toss out D. longissimum and create D. treleasei for those plants from further south.
I'm curious to know the reason for now (from the 1998 article) making D. longissimum var. treleasei.
Greg