130 



THE CACTACEAE. 



121. Opuntia austrina Small, Fl. Southeast. U. S. 816. 1903. 



Opuntia youngii C. Z. Nelson, Chicago Examiner. June 13, 1915. 



Roots fusiform or tuberous, resembling sweet potatoes, often 4 to 6 cm. in diameter, 5 to 15 

 cm. long; stems erect or ascending; joints narrowly obovate to oblong-obovate, thick, tubercu- 

 late, repand, bright green, 5 to 12 cm. long; leaves soon deciduous, less than 10 mm. long; glochids 

 yellowish; spines usually on the upper half and margin of the joint, often 2, sometimes i to 6, from 

 an areole, whitish or pinkish, darker at base and apex, twisted, sometimes wanting; flowers bright 

 yellow, 6 to 7 cm. broad ; petals cuneate, truncate or retuse at apex, mucronate ; fruit 2.5 to 3 cm. long. 



FIG. 163. Opuntia austrina. Xo.5- 



Type locality: Miami, Florida. 



Distribution: Southern Florida. 



Opuntia youngii C. Z. Nelson, published in a Chicago newspaper, we have referred here, 

 after studying a specimen sent by the author. 



Opuntia spinalba Rafmesque (Atl. Journ. i : 147. 1832) was described as from the keys 

 of Florida, and answers in some respects to 0. austrina; but it is very unlikely that any 

 plants of the region inhabited by austrina were known to botanists as early as 1832. 



Figure 163 represents a plant collected by Dr. Small at the type locality in 1901. 



122. Opuntia macrorhiza Engelmann, Bost. Journ. Nat. Hist. 6: 206. 1850. 



Opuntia fusiformis Engelmann and Bigelow, Proc. Amer. Acad. 3: 297. 1856. 

 Opuntia rafinesguei fusiformis Engelmann, Pac. R. Rep. 4: 43. 1856. 

 Opuntia mesacan/ha macrorhiza Coulter, Contr. U. S. Nat. Herb. 3: 430. 1896. 

 Opuntia xanthoglochia Griffiths, Rep. Mo. Bot. Card. 21: 166. 1910. 

 Opuntia roseana Mackensen, Bull. Torr. Club 38: 142. 1911. 



Plant low, usually nearly prostrate, forming a clump i meter in diameter, from a cluster of 

 tuber-like roots, these sometimes 5 to 7.5 cm. in diameter; joints orbicular to obovate, dull green, 

 5 to 1 6 cm. long, about i cm. thick; leaves subulate, 4 to 10 mm. long; areoles rather large, the lower 

 ones and sometimes all of them spineless ; glochids numerous, yellow or brown; spines, when present, 

 i to 4, unequal, yellow to brown, the longest 2.5 cm. long; flower yellow, with a reddish or purplish 

 center, 7 to 8 cm. broad; fruit narrowly obovoid, 3.5 to 5 cm. long, purple or red, with a depressed 

 umbilicus, not edible; seeds 5 mm. in diameter, with broad margins. 



Type locality: Rocky places on the Upper Guadalupe, Texas. 

 Distribution: Missouri and Kansas to Texas. 



Opuntia seguina C. Z. Nelson (Galesburg Register, July 20, 1915), published in a news- 

 paper, and said to have come from San Antonio, Texas, seems to be one of the Tortispinac, 



