Dasylirion quadrangulatum, Toothless Sotol or Mexican Bear Grass, is a magnificent smooth-leaved Sotol from the NE Mexican states of Tamaulipas and Nuevo León where it grows to elevations of 2000m on dry rocky hillsides. It is a spectacular species, growing large and developing a stout trunk and its long thin smooth foliage is a striking contrast from other Dasylirion species which are usually toothed.

It requires a well-drained rocky substrate, slightly alkaline and is best grown on a raised xeric bed or sloping gradient to ensure its roots remain as dry as possible during winter. It is best to grow Dasylirion quadrangulatum in full sun. Grown like this, with good drainage and full sun it is hardy down to about -10C.

There has been some confusion over the correct taxonomic name for this species and its synonyms however the Royal Botanic Gardens, Kew cites Dasylirion juncifolium as an acknowledged synomyn.