PLANTS I'UKNlSHlNt; M KDICI N AL LEAVES AND 1 1 KKBS. 



37 



GUM PLANT. 



(1) GrindeUa rohusLa Null.; (2) GnndcUu squarrosd (Pursh) Dimal. 



Pharmaco panel I name. — Grindelia. 



Other common names. — (2) IJroad-leaved gum plant, scaly grindelia. 



Habitat and range. — The gum plant (Grindelia robusta) occurs in the States west 

 of the Rocky Mountainti, while the broad-leaved gum plant (G. s(piarrosa) is more 

 widely distributed, being of common occurrence on the plains and prairies from the 

 Saskatchewan to Minnesota, south to Texas and Mexico, and westward to California. 



Description . — The name 

 "gum plant" is applied 

 especially to Grindelia 

 robusta on account of the 

 fact that the entire plant 

 is covered with a resinous 

 substance, giving it a 

 gummy, varnishedappear- 

 ance. It is an erect per- 

 ennial herb belonging to 

 the aster family (Aster- 

 ace*) and has a round 

 smooth stem, about l^- feet 

 in height. The leaves are 

 pale green, leathery in 

 texture and rather rigid, 

 coated with resin and 

 showing numerous trans- 

 lucent dots, and are about 

 an inch in length. In out- 

 line they are oblong spat- 

 ulate^that is, having a 

 broad, rounded top gradu- 

 ally narrowing toward the 

 base — clasping the stem 

 and with margins some- 

 what saw toothed The 

 plant branches freely near 

 the top, each branch some- 

 what reddish and termi- 

 nating in a large yellow 

 flower. The yellow flowers 

 are about three-fourths of 

 an inch in diameter, 

 broader than long, and 

 are borne singly at the ends of the branches. Immediately beneath the flower is a 

 set of numerous, thick, overlapping scales (the involucre), the tips of which are 

 rolled forward, the whole heavily coated with resin. 

 219 



Fig. 29.— Scaly grindolia {Grindelia squarrosa), leaves and flowrrs. 



