GENUS 12. 



THISTLE FAMILY. 



37 1 



12. GRINDELIA Willd. Gesell. Nat. Fr. Berl. Mag. i : 260. 1807. 



Perennial or biennial herbs, sometimes woody at the base, with alternate sessile or clasp- 

 ing leaves, usually spinulose-dentate, and rather large heads of both discoid and radiate 

 yellow flowers, solitary at the ends of the branches (rays rarely wanting). Involucre hemi- 

 spheric or depressed, its bracts imbricated in several or many series, usually subulate-tipped. 

 Receptacle flat or convex, naked, foveolate. Ray-flowers fertile. Disk-flowers perfect, or 

 sometimes only staminate. Anthers obtuse and entire at the base. Style-branches narrow, 

 flattened, their appendages linear or lanceolate. Achenes short, thick, sometimes compressed, 

 glabrous, 4-5-ribbed. Pappus of 2-8 soon deciduous awns or bristles. [Named for Prof. H. 

 Grindel, of Riga, 1776-1836.] 



About 30 species, natives of western North America, Peru and Chile. Besides the following, 

 some 15 others occur in the western and southwestern parts of North America. Known as Gum- 

 plant or Tar-weed. Type species : Grindelia inuloides Willd. 



Leaves spatulate or oblong, obtuse or obtusish ; achenes truncate ; bracts squarrose. 



Leaves linear or linear-oblong, acute ; achenes i-2-toothed ; bracts not squarrose. 



1. G. squarrosa. 



2. G. lanceolata. 



i. Grindelia squarrosa (Pursh) Dunal. Broad-leaved Gum-plant. Fig. 4192. 



Donia squarrosa Pursh, Fl. Am. Sept. 559. 1814. 

 Grindelia squarrosa Dunal in DC. Prodr. 5 : 



3i5- 1836. 



G. grandiflora Hook. Bot. Mag. pi. 4628. 1852. 

 Grindelia nuda Wood. Bot. Gaz. 3: 50. 1878. 

 Grindelia squarrosa nuda A. Gray, Syn. Fl. i 2 : 



1 1 8. 1884. 



Glabrous, erect or ascending, branched, 

 io'-2 high. Leaves oblong or oblong- 

 spatulate, obtuse, more or less clasping at 

 the base, sharply spinulose-dentate, some- 

 times laciniate, i'-ii' long, 3" -6" wide; 

 heads io"-i,s" broad, very glutinous ; bracts 

 of the involucre linear-lanceolate,, subulate- 

 tipped, strongly squarrose ; achenes trun- 

 cate, those of the outer flowers usually 

 thicker than those of the inner; rays up to 

 i' long or wanting; pappus of 2 or 3 awns. 



In dry soil, Illinois and Minnesota to Mani- 

 toba, Missouri, Texas, Arizona and Mexico. 

 Adventive in southern New Jersey, Pennsyl- 

 vania and New York. June-Sept. 



2. Grindelia lanceolata Nutt. Nar- 

 row-leaved Gum-plant. Fig. 4193. 



Grindelia lanceolata Nutt. Journ. Acad. Phil. 

 7:73- 1834- 



Slender, erect, glabrous, branched, about 

 2 high. Leaves lanceolate or linear, acute 

 at the apex, sessile or clasping at the base, 

 spinulose-dentate, laciniate, or the upper 

 entire, i'-2' long, 2" -5" wide; heads nearly 

 as large as those of the preceding species; 

 bracts of the involucre linear-subulate, the 

 inner erect, the outer spreading; achenes 

 i-2-toothed; pappus of i or 2 awns. 



In dry soil, Tennessee to Missouri, Kansas, 

 Louisiana and Texas. July-Sept. 



