38 ADDISONIA 
belongs the Prickly Pear of the Eastern States, Opuntia Opuntia 
(Linnaeus) H. Karst., the type of the genus. 
It inhabits poor soil in Texas and Arkansas, has been reported to 
extend northward into Missouri and Kansas, and may range east- 
ward into Louisiana. It was discovered by Ferdinand Lindheimer 
in 1847, in naked, sterile, rocky places on the Upper Guadalupe 
River, Texas. It does not respond well to greenhouse cultivation, 
and is not hardy at New York; it has long been grown in gardens of 
southern Europe. The plant from which our illustrations were 
made was sent from Kerrville, Texas, by Mr. B. Mackensen, in 
1910, and flowered at the New York Botanical Garden in Febru ry, 
1912, ripening its fruit in May; it is a part of the collection which 
Mr. Mackensen named Opuntia Roseana. 
Recently (Plant World 19: 141-144. 1916) Dr. David Griffiths 
has expressed the opinion that the type of this species has been 
misinterpreted by botanists since its original description in 1850 by 
Dr. Engelmann and that the name macrorhiza belongs to another 
Texan species, O. Mackenseni Rose, which also grows at Kerrville, 
Texas. References to the type specimen, however, preserved in the 
herbarium of the Missouri Botanical Garden, and to the original 
description do not satisfactorily support his contention. The plant 
was well illustrated by Dr. Engelmann on plate 69 of the United 
States and Mexican Boundary Survey report, published in 1859, 
and has since been depicted in several other publications, but 
not hitherto in color. Opuntia leptocarpa Mackensen (Bull. Torrey 
Club 38: 141. 1911), a plant found at San Antonio, Texas, which 
has flowered several times at the New York Botanical Garden, 
appears to bea natural hybrid between this species and Opuntia 
Lindheimeri Engelm. 
N. L. BRITTON. 
EXPLANATION OF PLATE, Fig. 1,—Joint with fruit. Fig. 2—Joint with 
