furthermore, is the fullest development of the tubular floral structure, much less evident in echinocactus and mamillaria. Thus we find the cacti forming a little kingdom of their own, and could we here go beyond the limits of an outline, a broadly interesting study might be found in each division of the order. But without further detail the vitally important observation may be made, that there seems just reason to believe that what the Compositæ are to modern plant life in general, the Cactaceæ were, and
Fig. 7.—Yucca Group: 1, Yucca macrocarpa; 2, Yucca træculeara; 4, Yucca elata; 3 and 5, Yucca dasylirion.
probably are, to that ancient Southwestern flora—the climax of its evolution.
Linnæus vividly expressed the spirit of the "century plant" in one Greek word, the very name he gave it—"Agave," so called, he said, "because that word indicates something grand and deserving admiration"; and although he only knew a half-dozen species, the many that subsequent research has brought to light justify most fully the title he bestowed. The genus holds a station of its own in the foremost ranks of monocotyledons, but, like the cacti among dicotyledons, rather isolated. It certainly approaches the amaryllis family in many characteristics, and, if really coming within the limits of this order at all, may perhaps
