1180 CARDUACEAE 



23. GRINDELIA Willd. 

 Perennial or rarely annual or biennial herbs, or shrubby plants, usually with glabrous 

 or glutinous foliage. Leaves alternate : blades mostly spinulose-toothed, sessile or clasp- 

 ing. Heads relatively large, radiate or rarely discoid, often in corymbs. Involucres 

 hemispheric or depressed, many-flowered : bracts in several series, usually with subulate 

 tips. Receptacle pitted. Ray-flowers pistillate, fruit producing, rarely wanting. Disk- 

 flowers perfect or sometimes staminate. Stigmas narrow, flattened, with linear or lanceolate 

 appendages. Achenes 4-5-ribbed, sometimes flattened. Pappus of 2-8 awns or bristles, 

 early deciduous. Gum-plant. 



Stems pubescent, at least above. 



Involucres less than 1 cm. broad. 1. G. microcephala. 



Involucres over 1 em. broad. 2. G. inuloides. 



Stems glabrous throughout. 



Achenes without teeth or auricles at the top. 



Involucres less than 1.5 cm. broad : leaf-blades with gland-tipped teeth. 3. G. squarrosa. 



Involucres over 1.5 cm. broad : leaf-blades with very sharp, sometimes spinu- 



lose, teeth. 4. G. rjrandiflom. 



Achenes with 1 or 2 teeth or auricles at the top. 5. G. Innccolata. 



1. Giiiidelia microcephala DC. Stems minutely pubescent, 2-5 dm. tall, branclied. 

 Leaf-blades oblanceolate to oblong or oblong-ovate, 1-4 cm. long, acute or acutish, closely 

 toothed to the partly clasping base, the teeth gland-tipped : involucres 5-7 mm. high ; bracts 

 linear or nearly so, with green spreading tips : achenes 3 mm. long, oval, ridged. 



On plains, Texas. Spring and summer. 



2. Grindelia inuloides "Willd. Stems minutely jnibescent, 3-7 dm. tall, simple or 

 sparingly branched. Leaf-ldades oblong, oblong-lanceolate or nearly ovate, or sometimes 

 broadest above the middle near the base of the stem, 1,5-5 cm. long, acute, closely toothed 

 to the partly clasping base, the teeth gland-tipped : involucres about 1 cm. high ; bracts 

 linear or nearly so, with green spreading tips : achenes 4 mm. long, broadest near the 

 rounded truncate top. 



On plains, Arkansas and Texas. Summer and fall. 



3. Grindelia squarrosa (Pursh) Dunal. Stems glabrous, 3-8 dm. tall, branched 

 above. Leaf-blades oblong-spatula te to oblong, 2-5 cm. long, acutely or spinose-serrate, 

 partly clasping : heads sometimes numerous : involucres about 1.5 cm. broad, glutinous ; 

 bracts linear-lanceolate, prolonged into slender leathery tips, the inner erect or ascending, 

 the outer spreading or recurved : ray-flowers usually present ; ligules bright yellow : 

 achenes with 2-3 pappus-awns. 



In dry soil, Minnesota and Manitoba, to Illinois, Texas, Nevada and Mexico. Summer and fall. 



4. Grindelia grandiflora Hook. Stems glabrous, pale red and shining, 5-12 dm. tall, 

 usually simple below. Leaf-blades lanceolate to oblong-ovate or ovate, 1.5-5 cm. long, 

 sharply and closely toothed, sessile, or the upper ones partly clasping : heads showy : invo- 

 lucres about 1.5 cm. broad, 1 cm. high; bracts linear-lanceolate to linear: ray-flowers 

 present ; ligules yellow, 1.5-2.5 cm. long : achenes with 2-3 pappus-awns. 



On plains and prairies, Texas. Spring and summer. 



5. GrindeUa lanceolata Nutt. Stems 5-8 dm. tall, glabrous, sparingly branched 

 above. Leaf-blades lanceolate to linear-lanceolate, 2-8 cm. long, acute or slightly acumi- 

 nate, sessile, serrate, sometimes shallowly so, or those near the base of the steni laciniate : 

 heads showy: involucres about 1.5 cm. broad ; bracts produced into linear-filiform tips, 

 the outer bracts with spreading tips : achenes with 1-2 tooth-like pappus scales at the top. 



On plains or prairies, Missouri and Kansas to Tennessee, Louisiana and Texas. Summer. 



24. HETEROTHECA Cass. 

 Annual or biennial caulescent lier))s, with pubescent foliage. Leaves alternate : 

 blades flat, entire or toothed, commonly sessile above the base of the stem. Heads radiate, 

 showy, in panicles. Involucres hemispheric or campanulate, many-flowered : bracts nar- 

 row, in several series, the inner successively longer. Receptacle flat, pitted. Ray-flowers 

 pistillate. Disk-flowers numerous, perfect, or some of them staminate. Corollas yellow. 

 Stigmas with triangular or lanceolate appendages. Achenes various, those of the disk 

 more flattened than those of the ray. Pappus various, that of the ray of few caducous 

 bristles, or obsolete, that of the disk double, the outer of scales or stout bristle-s, the inner 

 of numerous rough hair-like bristles. 



