We don't have an entry for A. x spinosissima, so there was no need to delete it. It's listed only as an also-sold-as name, which does not imply any degree of validity, so it can remain in the database in that capacity.
As for the entry in question, it's clear that it can't be A. arborescens 'Dwarf,' so I've removed the species name, but I've added A. arborescens 'Dwarf' as an also-sold-as name because San Marcos Growers refers specifically to it as such.
http://www.smgrowers.com/produ...
The result is an entry with the rather silly name of Aloe 'Dwarf.'
I'll grant that this does not seem ideal, even with the two also-sold--as names. The only other solution I can offer, because we don't list man-made hybrids in our database, is a change that would name the entry Aloe 'Spinosissima,' treating the hybrid as a cultivar name and eliminating the 'Dwarf' label (although it would remain in the entry as an also-sold-as name). What do you think of this second solution?