Ag. sp. FO-076 / sp. Sierra Mixteca at Rio Capala
(photo courtesy of Bertus Spee)

 

There have been plants doing the rounds as Agave titanota ( see above pictures ) but quite unlike the plant defined by Gentry which has bluish-white leaves and found in habitat at Rancho Tambor in Oaxaca. It has been debated for some time as to whether these plants are a separate entity or simply a green form of titanota. There are also bluish forms of these plants. The situation is further complicated by the fact that both forms hybridise with each other and also with agave kerchovei.
They have appeared as sp. FO-076, sp. Sierra Mixteca , sp. Nr.1 and more recently as horrida ssp.oteroi. As they has been found occasionally growing alongside plants similar to the true titanota they were thought by some to represent a variant in a highly polymorphic and variable species. However there has been a very recent well written travelogue to Oaxaca written up by Greg Starr et al. in which a visit to Rancho Tambor is described.
It is to be foundt at http://www.agaveville.org/viewtopic.php?f=3&t=4356. This excellent forum called Agaveville has a section called Agavaceae Talk in which this item appears plus further threads discussing the issue.
The true ,white leaved titanota, as described by Gentry was found at that location but the 'green titanota' disappeared on the trail, well short of reaching Rancho Tambor. The pendulum thus appears to swing in favour of the name titanota being applied only as per Gentry.
It was reported that a second location has been found for agave titanota, so Rancho Tambor no longer appears to be the sole habitat for these plants. Currently no further details are available until studies are complete.
The very latest development is that the green leaved form has been described as Agave oteroi by Greg Starr in the Summer 2019 issue of Cactus and Succulent Journal (Vol. 91 N. 2).
 
(photos courtesy of Greg Starr)