52 University of Texas Bulletin 



CISTACEAE Rock-rose Family 



Helianthemum rosmarini folium Pursh. Rock-rose. Frost Weed. 

 Postoak woods. 

 Southeastern states. 



Lechea tenuifolia Michx. Pin-weed. 

 Postoak woods. 

 Eastern states. 



VIOLACEAE Violet Family 



Calceolaria verticillata Kuntze (Ionidium poly galae folium Vent.) 

 Nodding Violet. Green Violet. 

 Roadsides, University campus, etc. 

 Southern plains and prairie states. 



Viola missouriensis Green. Blue Violet. 



In moist, rich soil in ravines. Barton Creek, Onion Creek. 

 Not abundant here. 

 Southern central states. 



OPUNTIALES 



OPUNTIACEAE (CACTACEAE) Cactus Family 



Cactus missouriensis Kuntze (Mammillaria missouriensis Sweet.) 



Nipple Cactus. 

 Dry soil. Not common here. The plant is nearly spherical, one or 

 two inches high and covered with cylindrical tubercles. 

 Plains and prairie states. 



Echinocatus texensis Hoepf. Devil's Pin-cushion. 



Very common in dry open ground on hillsides and uplands. The 

 large round ridged apex of the plant, covered with stout pink thorns, 

 usually just appears above the surface of the ground. 



Southern Texas and Mexico. 



Echinocactus setispinus Engelm. 



Dry hillsides. The nearly globular stems are from two to four 

 and a half inches in diameter, and with long slender spines. 



Texas and Mexico. 



Echinocereus caespitosus Engelm. & Gray. 



Dry hillsides. One of our most abundant species. The short 

 cylindrical stems are usually clustered. The clustered spines are 

 short and spreading, giving a peculiar scale-like appearance. 



Southern plains states to Mexico. 



