46 University of Texas Bulletin 



Poinsettia heterophylla Small. {Euphorbia heterophylla L.) Pointed 

 Leaf. 

 Waste places. 

 Central and southern states. Tropical America. 



Ricinus communis L. Castor Bean. 



Occasional in ravines, etc. Escaped from cultivation. 



Tropics, sub-tropics. 



Thought to have originated in Africa or India. 



Stillingia linearifolia Kl. & Garcke. (S. angustifolia Engelm.) Queen's 

 Delight. 

 Common on dry hillsides. 

 Texas, New Mexico, and Mexico. 



Tithymalus. arkansanus Kl. & Garcke. (Euphorbia dictyosperma, 

 F. & M.) Spurge. 

 Plains and prairie states to Mexico. 



Tithymalus com/mutatus Kl. & Garcke. (Euphorbia commutata 

 Engelm.) Spurge. 

 Ravines and moist banks. Abundant along Barton Creek. 

 Eastern states. 



Tithymalus longicuris Small. (Euphorbia Longicuris Scheele.) 

 Spurge. 

 Open, dry ground. Abundant on the campus. 

 Southern prairie states. 



Tithymalus Missouriensis Small. (Euphorbia arkansana var. Mis- 

 souriensis Norton.) Spurge. 

 Open ground. 

 Plains and prairie states. 



Tithymalus Roemerianus Small. (Euphorbia Roemeriana Scheele.) 



Spurge. 

 Southern Texas. 



Tragia nepetaefolia Cav. 

 Dry ground. 

 Southern central states and Mexico. 



Tragie ramosa Torr. 



Abundant in dry open ground. University campus. 

 Sounthern plains and prairie states. 



