W86 

 (leaf 2) 

 GUMWEEDS 



Grinde'lia spp. 



Gumweeds compose a moderate-sized group of coarse, annual, bi- 

 ennial, or perennial herbs, sometimes woody at the base, native to 

 western North and South America, and particularly well represented 

 in the United States west of the Mississippi. Grindelia is a very 

 homogeneous group of plants, easily distinguished by clear-cut char- 

 acters. However, as is the case with certain other well-marked and 

 distinctive genera (e. g., Rucbus, Saline, Viola), considerable varia- 

 tion and instability within the genus itself makes specific boundaries 

 difficult. 1 Although the species total has long been estimated at 25 

 or 30, the genus in its entirety has not been carefully studied ; recent 

 intensive study, both in North and South America, indicates that the 

 number of species is probably greater than has hitherto been sup- 

 posed. The eminent German botanist, Karl Ludwig Willdenow, 

 named this genus in honor of David Hieronymus Grindel (1776- 

 1836), a Kussian professor and botanical author. The resinous 

 character of many species has given rise to the common names, gum- 

 weeds, gumplants, and rosinweeds; the flower heads usually exude 

 the most of this medicinal resin. 2 3 



These plants grow on a variety of sites at medium elevations. 

 Many species prefer dry, rocky, or gravelly situations, often appear- 

 ing along water courses; some invade roadsides, embankments, and 

 waste ground ; still others inhabit saline or marshy sites, or grow oil 

 alkaline or limy soils. Despite moderate abundance in some regions 

 gum weeds possess little forage value and are relatively unpalatable 

 to all classes of livestock; presumably even goats refuse to eat them. 

 Local abundance of gumweeds is often an indication of depletion, due 

 to severe and prolonged overgrazing; the plants frequently form 

 dense stands on abused and abandoned dry-farming areas. 



Some species of gumweed were used by the Indians and early west- 

 ern settlers as a tonic and blood purifier. 6 The Indians also used 

 the resinous buds in the treatment of asthma and bronchitis. 4 Fluid 

 extract of grindelia, an official drug, is obtained from the flowering 

 tops and leaves of two species (either separately or in mixture) of 

 this genus, curlycup gumweed, and shore gumweed. These plants 

 are extremely hardy ; some species are cultivated for their ornamental 

 yellow flowers. 



Gumweeds have simple or branched stems, sometimes much- 

 branched from the base. The rather stiff, undivided leaves are 

 alternate, with sessile or partly clasping bases, or the lower leaves 

 may be short-stalked; they are commonly toothed on the margins, 

 hairless or occasionally hairy, and usually gland-dotted, sometimes 

 shining because of the resinous covering ; the herbage exudes a pleas- 

 ant, balsamlike odor. The rather large flower heads are solitary or 



1234 See footnotes on preceding page. 



6 Chesnut, V. K. PLANTS USED BY THE INDIANS OF MENDOCINO COUNTY, CALIFORNIA. 

 U. S. Dept. Agr., Div. Bot., Contrib. U. S. Natl. Herbarium 7 : 295-422, illus. 1902. 



