A DESERT GRAVEYARD 155 



the driest parts of South America, thriving always in the 

 gravelly or stony soils along the foothills and ba'jadas and 

 out on the broad desert mesas. The plants are globular or 

 cylindric and strongly ribbed with sharp stout thorns, sug- 

 gesting at once a barrel in size and shape, with its numerous 

 nails protruding from the circular staves. They grow 

 singly or in groups of two to four or more, from a foot to 

 three or four feet in height, sometimes reaching nine feet. 

 The central spines are the strongest and stoutest, usually 

 one or more hooked, the radial spines also stout; the radial 

 bristles or threads if present are at times rather firm and 

 sometimes quite weak in texture. The Echinocacti have no 

 spines on the ovaries or fruit — a characteristic which dif- 

 ferentiates them from the Echinocereus Cactus. 



In this great field of Bisnaga, the Barrel Cacti, or Visna- 

 glta, the little fellows, we have selected about fifteen typical 

 species although there are many other varieties. It is early 

 in the morning of a hot June day in southeastern Arizona 

 that we start on our sixth and last trek across the desert, 

 armed with notebooks and other paraphernalia of the student 

 or tourist, having selected our locale late the preceding day. 



Interlacing Spine Cactus (Echinocactus 



intertextus) 



Southeastern Arizona, Southwestern Texas, 

 and Northern Mexico 



Echinocactus intertextus, the Interlacing Spine Cactus, 

 signals our attention first, a rare and brightly flowered little 

 fellow. It is interesting to note that the name intertextus 

 refers to the numerous radial interlacing spines covering 

 this Visnagita in two or three whorls, and on the older plants 

 forming a dense lacework over the entire plant. Only an 

 inch and a half tall in many cases, sometimes reaching the 



