Hi Jim, You raised a question about the term Tubergenii Group. Its a cultivar group name i.e. a superset of cultivars which contains the cultivar 'Guinea Gold'. Someone somewhere has published the name Tubergenii Group, together with a description of the range of cultivars that it includes. The rules are laid down in the Cultivated Code. The aim with such a grouping is to pull together plants that have a horticultural relationship which are within a Denomination Class (as laid down by the Cultivated Code, which is normally a genus), but which otherwise may not be a very close botanical relationship. For example, it could be a group of variegated plants or a group of early flowering varieties. However, the groups that are normally chosen are close and are often a group of interspecific hybrids. An appropriate example taken from the Code might be in Iris, the Dutch Group, which includes the complex of early flowering cultivars arising mainly from I. tingitana, I. xiphium var. lusitanica and I xiphium var. praecox. Incidentally, one useful feature of such Groups for horticultural purposes is that a particular cultivar can be in more than one group, depending on the need of the author. Best regards, David Victor