A SOUTHWESTERN PLANT GROUP. 



797 



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 inter- 

 esting 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 Com- 

 positce, are to modern plant life in general, the Cactacece. were, and 



'wSmfc 



Fig. 7. — Yucca Group: 1, Yucca macrocarpa ; 2, Yucca treeuleara ; 4, Yucca elata ; 3 and 5, 



Yucca dasvlirion. 



probably are, to that ancient Southwestern flora — the climax of 

 its evolution. 



Linnaeus vividly expressed the spirit of the " century plant " 

 in one Greek word, the very name he gave it — "A gave," so called, 

 he said, " because that word indicates something grand and de- 

 serving 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 sta- 

 tion of its own in the foremost ranks of monocotyledons, but, like 

 the cacti among dicotyledons, rather isolated. It certainly ap- 

 proaches the amaryllis family in many characteristics, and, if 

 really coming within the limits of this order at all, may perhaps 



