MY CONCEPTION OF OPUNTIA MACRORHIZA 



ENGELM.i 



DAVID GRIFFITHS 

 Bureau of Plant Industry, Washington, D. C 



Opuntia macrorhiza was described by Dr. Engelmann in the 

 Boston Journal of Natural History, volume 6, page 206, 1850. 

 The type plants were collected by Dr. Lindheimer in Texas, in 

 "naked, sterile, rocky places on the upper Guadaloupe" accord- 

 ing to the or ginal publication. 



The type is in the Engelmann Herbarium of the Missouri 

 Botanical Garden. A very important part of the exhibits in the 

 case is a note from Dr. Lindheimer attached to the type reading, 

 "between the Piccardinalis and Guadaloupe, fruit greenish, very 

 pleasant." Later, in 1856, on page 311 of the third volume of 

 the Proceedings of the American Academy of Arts and Sciences, 

 in discussing the geography of the cactus regions of the LTnited 

 States, Dr. Engelmann refers to the Guadaloupe, the "Pier- 

 denales," and the San Antonio rivers. Upon the modern maps 

 we have the Pedernales, a tributary of the Colorado. It has its 

 origin not far from that of the Guadaloupe and runs approxi- 

 mately parallel to that river for some distance. The main town 

 in this region is the village of Kerrville. The country is a rolling 

 broken region with scrub pines, junipers and oaks abounding. 

 Bare rocky hills and ridges where p.dckly pear abounds are 

 decidedly characteristic of a large section of this part of Texas. 

 A tuberous-rooted species of Opuntia is abundant and conspicu- 

 ous all through the region and in my opinion it must be Opuntia 

 macrorhiza. The type was collected by Lindheimer in 1847. 

 In 1850 and 1851 he sent other material to Dr. Engelmann which 

 he considered the same species and which he secured at New 

 Braunfels. There is very clear evidence, as pointed out by the 



' Published by authority of the Secretary of Agriculture. 



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