Location: N of Monterrey, Nuevo Leon

A. trigonus LRM316, a large plant growing in the shelter of a bush.

Comments

Anderson’s neotype locality for this plant is from this area to the north of Monterrey. The plant has been reported as extinct here having succumbed to the plough and livestock farming, however we had very little difficulty in locating specimens despite the activities of livestock. The population though does appear to be small. The plant is very typical of the trigonus plants seen much further south in Tamaulipas, although flowering had finished when we saw them in late October 2001.  The plant grows on flat stony land usually under low scrub, the largest and healthiest specimens being found in the protection of bushes.