Seed Plants, Ferns, Fern Allies of the Austin Region 33 



Silphium albiflorum Gray. Rosinweed. 

 Dry hillsides of the Edwards Plateau. 

 Texas. 



Silphium asperrimum Hook. Rosin-weed. 

 Dry ground. Rare. 

 Southern plains and prairies. 



Tetragonotheca Texana Gray & Engelm. 



Very common in fields, roadsides and open woods. Easily recog- 

 nized by its square involucre of four large outer bracts. 



Texas and Mexico. 



Thelesperma sub simplici folium. A. Gray. 

 Common in dry ground. Similar to Coreopsis. 

 Rays yellow. 

 Arizona to Texas and Mexico. 



Thelesperma trifidum Britton. (T. filifolium Gray.) 



Abundant in open, dry ground. Similar to the preceding. 

 Arkansas and Texas. 



Verbesina virginica L. Crownbeard. Frostweed. Ice Plant. 



Common in low, open ground, roadsides and waste places. A 

 coarse, rough-leaved plant, sometimes six feet tall, with white flower 

 clusters. It is easily recognized by its large leaves and winged 

 stems. 



Southeastern states. 



Viguiera helianthoides H.B.K. 



Valleys, hillsides, open ground or open woods. 

 Texas to Arizona and in Mexico. 



Ximenesia encelioides Cav. (Verbesina encelioides Benth. & Hook.) 

 Waste places. Abundant on roadsides on the river flood plain. 



Very similar to Helianthus praecox, but with winged fruits. 

 Southern plains states to Florida. 



Zexmenia hispida Gray. 



Dry hillsides. Mt. Bonnell. 

 Texas and Mexico. 



Tribe HELENIEAE 



Amblyolepis setigera DC. 



River flood plain and on uplands. 

 Texas prairies. 



