Calibanus hookeri, diameter 18 cm (No. 6)

Origin from North central Mexico (San Luis Potosi).
The form of this plant is much like a trunk less bear grass (Nolina). 
Caudex topped by perennial grassy looking silver-blue leaves, up to 90 cm long and expanded from a woody base.
This swollen trunk is often exposed in cultivation by caudiciform enthusiasts.
It withstood temperatures of -17°C, but its exact hardiness is unknown.
Because of its extreme drought tolerance it makes a great container plant for light shade to full sun, or is an excellent foliage accent to the dry garden in warm regions.