There has long been confusion about the identification of two arboreal yuccas that grow commonly here in southern California. The more massive of the two, with large swollen basal stems and 12- to 18-inch-long light green leaves with a soft tip and small marginal teeth, was long considered to be Yucca elephantipes by those most familiar with the plant, but it was also commonly called Yucca gloriosa in the nursery trade. The other plant which has broader and longer more luxurious glossy leaves and heavy stems without as much basal swelling has also been commonly referred to as Yucca elephantipes. To avoid the discussion regarding nursery nomenclature, we will submit that the nursery industry often gets botanical names wrong much of the time. That being said however, there was enough discrepancies in the written reference material on these plants that we decided initially to go with the flow from 1979 until 2001 and continue to call the shorter leaved heavier stemmed plant Yucca gloriosa while calling the larger leaved one Yucca elephantipes.

After many years of urging by friends more knowledgeable than us on this subject we decided in 2001 to change our listing for the plant we had long called Yucca gloriosa to Yucca elephantipes. This action was buoyed by David Ferguson's statement in the May-June 2001 issue of the Cactus & Succulent Journal (V.73 N.3 pg. 140) where he addressed this issue when reviewing Mary and Gary Irish's Agaves, Yuccas and Related Plants and noting that they made this same identification error. In this review Ferguson stated "I noticed only one error. This is the result of the common misidentification of Yucca elephantipes as Y. gloriosa which has been perpetuated by growers and nurseries for many decades." To make it clear that we were still growing the same plant as before, but we now list it as "Yucca elephantipes [Y. gloriosa, Hort.]".

To add further confusion to this situation it has become evident that the name Yucca elephantipes is not actually this plant's currently accepted name. Though we continue to use the name Yucca elephantipes since historically it has long gone by this name and for convenience so not to confuse our staff and customers, this plants currently correct name is Yucca gigantea. It was first validly described as such by the French botanist Charles Lemaire in 1859, though earlier that same year the German horticulturalist, Eduard von Regel, wrote of a Yucca with a thickened base, calling it Yucca elephantipes to distinguish it from Yucca aloifolia and the American botanist William Trelease used the name Yucca elephantipes in his 1902 Annual Report of the Missouri Botanical Garden, referring to Regel's 1859 publication. Unfortunately, von Regel did not actually formally describe the plant and Lemaire's later naming of it would take precedence, so the name Yucca elephantipes is now considered "nomen illegitimum" meaning it an illegitimate name.

Having made the decision to call the common large yucca with its swollen base by its nomen illegitimum as Yucca elephantipes name, we are still in a quandary what to call the yucca with the longer more luxiourious foliage that we had previously called "Yucca elephantipes"? It certainly does not resemble the description for the true Yucca gloriosa, which is a still narrow leafed species that comes from sandy lowlands of the southeastern US. The plant has 3-4 feet long by up to 4 inch wide leaves and like Y. elephantipes it is flexible and has a soft tip and small marginal teeth. The lower surface of the leaves are roughly the same color and texture as what we now call Yucca elephantipes but the leaf size and the glossy darker green upper surface are very different. These plants are both growing in Santa Barbara in very similar conditions, so this is not a case of how a plant performs in one climate vs another as has been suggested in usenet discussions on Yucca elephantipes. These are two distinctly different plants.

Dylan Hannon, curator of the Huntington Botanic Garden Conservatory took this up with Dr. Lee Lenz at Rancho Santa Ana Botanic Garden who cited "Flora Mesoamericana" as giving Y. guatemalensis as the correct name for our the large swollen stemmed plant with shorter rougher textured leaves that we have called Y. gloriosa in California but then noted that the treatment of the genus by Dr. Joachim Thiede (Institute of Botany and Botanical Garden of the University of Hamburg) in The Illustrated Handbook of Succulent Plants (2001) then listed Yucca elephantipes Regel as the valid name with Y. guatemalensis Baker and Y. gigantea Baker as synonyms and noting that Emily Jane Lott and Abisai Garcia-Mendoza in their 1994 treatment of Agavaceae the Flora of Mesoaericana and USDA 2001 The Plants database erroneously used the younger synonym Y. guatemalensis for this species. If we conclude that Yucca elephantipes is the current name for this species and it is synonymous with Y. guatemalensis and Y. gigantea, this still doesn't give us a clue as to what the name is for the more tropical, longer leaved plant picture below. Dr. Joachim Thiede's treatment in the updated The Illustrated Handbook of Succulent Plants (2020) and that in all more modern databases such as Kew's Plants of the World Online has Yucca elephantipes now as a synonym with Yucca gigantea as the valid name, so perhaps they are all best called Yucca gigantea.