In May of 2019 on a trip with Julia Etter, Kelly Griffin and Tony Krock in Oaxaca, we were driving to the type locality of Agave gypsicola in San Juan Teita. On the way all our eyes, as usual, were scanning the mountainsides when we noticed an agave growing in the distance. Also, as usual, we were torn between stopping to take a look and continuing to the plants at the destination. Time is always a factor on these trips, so much of it windshield time, the hours spent getting from habitat to habitat eating up the day. The horizon was too tempting this time to not stop and take a look. We obtained permission from a farmer to cross his fields and climb the mountain to see the plants. Once we got to the plants all four of us were unable to key out them out, other than being a member of the Section Heteracanthae, along with Agave horrida, titanota, xylonocantha, ghiesbreghtii, etc. The agaves were medium sized, approximately 3'x3' or more, that resembled a mix of Agave horrida and green titanota/oteroi. The agaves continued for quite a ways up the mountainside, but we had to pull ourselves away in order to get to the original destination. Tony named the plants, 'Green Bull', for their color and the intimidating bull we had to get past in order to get to the plants. C'mon Tony, that's every habitat in Mexico.

On a a trip in January of 2023, Tony Krock &  I guided Greg Starr & Gonzalo Juarez to these plants. In 2024 the two published a description of this agave as Agave yucuanensis, as they are found near the municipality of San Bartolomé Yucuañe in Northern Oaxaca. The flower stalk is paniculate, and their flower is described as greenish white flushed with reddish to purple tips. Hardiness remains to be seen, I have mature plants in the ground at my nursery that have handled temperatures in the low 30°s without issue.