A. xylacantha

(woody-spined).* fl. green, 1½in. long; spike dense, rather shorter than the scape, its bracts linear-subulate; scape 5ft. to 6ft. long, its bracts subulate, all ascending, the lower ones 6in. to 8in. long. l. not more than twenty in a stemle rosette, ensiform, diverging irregularly and often curving, 1½ft. to 3ft. long, 2in. to 3in. (rarely 4in.) broad at the middle, narrowed gradually upwards, a slightly glaucous dead green, marked with a few darker green lines on the back, furnished with a broad continuous horny border and a few very large irregular hooked teeth, often united or collected in pairs, ½in. to ¾in. long, and ⅜in. to ½in. broad; terminal spine brown, pungent, 1in. long. Mexico. A long-known, widely-spread, and distinct species. S YNS. A. amurensis and A. Vanderdonckii.