=A. heteracantha= (various-spined).* _fl._ greenish, 1-1/2in. long, on a dense spike 3ft. long; scape 3ft. to 4ft. long. _l._ fifty to eighty in a rosette, rigid, ensiform, 1-1/2ft. to 2ft. long, 2in. to 2-1/2in. broad in the middle, dull green, with numerous darker green lines on the back; terminal point 1in. long; side spines numerous, strongly hooked, lanceolate. Stemless. Mexico.
=A. Hookeri= (Hooker's).* _fl._ large, yellow, very numerous, in stalked panicled cymes. _l._ thirty to forty in a sessile rosette, 8ft. or 9ft. in diameter, oblanceolate-spathulate, bright green on the face, rather glaucous on the back, 4ft. to 5ft. long, 5in. to 9in. broad, 2in. to 3in. thick; terminal spine 2in. long, and decurrent for nearly half a foot; face flattish or slightly concave; side prickles irregular, brown and horny, about 1/4in. long, and curved in different directions. Mexico. SYN. _A. Fenzliana_. A rare and noble species, very massive.
=A. horrida= (horrid).* _fl._ unknown. _l._ thirty to forty in a dense rosette, rigid, lanceolate-spathulate, 8in. to 12in. long, 1in. to 2in. broad, bright green; terminal spine pungent, nearly 1in. long; margin furnished with a continuous broad grey border, with copious prickles 3/8in. to 1/2in. long.
=A. h. Gilbeyi= (Gilbey's).* _l._ about thirty, 3in. to 4in. long, 2in. broad, dark green with a pale stripe down the middle, three to four large spines on each side. Mexico, 1873.
=A. h. lævior= (smoother). _l._ somewhat narrower, longer, with marginal spines less strongly developed, and of a paler colour. Mexico, 1870.
=A. h. macrodonta= (long-toothed). _l._ fifty to sixty, 2-1/2in. broad; spines larger than in the typical form. Mexico, 1876.
=A. h. micrantha= (small-toothed). Border of leaf narrower, and spines smaller, than in the typical form.
=A. Jacobiana= (Jacob's). Synonymous with _A. Salmiana_.
=A. Kerchovei= (Kerchove's).* _fl._ unknown. _l._ thirty to forty in a stemless rosette, stiff, rigid, typically ensiform, 6in. to 12in. long, 1-1/2in. to 2in. broad, narrowing gradually to a pungent spine 1in. long, dull green, with a distinct pale central band, rounded on the back, without any stripes of dark green, the margin with a continuous moderately broad grey border; side prickles irregular, grey, lanceolate, curved, 1/6in. to 1/4in. long. SYN. _A. Beaucarnei_.