THISTLE FAMILY 847 



9. GRINDELIA Willd. GUM-PLANT, RESIN-WEED. 



Coarse biennial or perennial herbs (some western species even shrubby), 

 usually with glabrous and glutinous foliage. Leaves alternate, usually spinu- 

 lose-toothed. Heads relatively large, radiate or rarely discoid, often corymbose, 

 many-flowered. Involucres hemispheric or depressed; bracts imbricate,* usually 

 with subulate_ spreading or recurved tips and mostly gummy; receptacle pitted. 

 Ray-flowers pistillate, fertile, with yellow ligules, or rarely wanting. Disk-flowers 

 hermaphrodite, usually fertile; corolla yellow. Stigmas narrow, flattened, with 

 linear or lanceolate appendages. Achenes 4-5-ribbed, sometimes flattened; pap- 

 pus of 2-8 awns or bristles, early deciduous. 



Involucres not viscid. 1. G. platylepis. 



Involucres more or less viscid. 



Leaves all entire, the basal ones 3-4 dm. long; bracts narrowly linear-lanceolate, the 



outer nearly filiform, rather thin. 2. G. oregana. 



Leaves, at least the basal ones, more or less dentate, the latter less than 2 dm. long; 



bracts lanceolate, with thick, rather fleshy tips. 

 Heads radiate. 



Pappus-awns apparently smooth; barbules seen only under a compound micro- 

 scope. 

 Tips of the outer bracts spreading, none reflexed. 



Stem-leaves serrate. 3. G. decumbens. 



Stem-leaves laciniate. 4. G. laciniata. 



Tips of the bracts squarrose, those of the outer ones strongly reflexed. 

 Stem-leaves oval, ovate, or ovate-oblong with a broad base. 



Leaves bluish green, spinulose-dentate ; heads very broad and flat, 

 its bracts broad and even the squarrose tips flattened. 



5. G. texana. 

 Leaves yellowish green, merely dentate; heads hemispherical, its 



bracts narrow and with terete squarrose tips. 6. G. squarrosa. 

 Stem-leaves oblanceolate, rarely oblong. 



Pappus-awns scarcely longer than the achenes, curved and twisted. 

 Squarrose tips of the bracts short; leaves subentire. 



7. G. integerrima. 

 Squarrose tips of the bracts long and slender; leaves serrate, with 



spreading teeth. 8. G. Brownii. 



Pappus-awns decidedly longer than the achenes, straight. 

 Leaves all finely serrate, dentate or subentire. 



Leaves finely and closely serrate. 9. G. serrulata. 



Leaves rather remotely dentate or subentire. 



10. G. perennis. 

 Leaves coarsely toothed, the basal ones sublaciniate. 



11. G. subincisa. 

 Pappus-bristles distinctly barbellate; barbules distinctly seen with a common 



pocket-lens. 



Stems tall, 4-8 dm. high, usually solitary; stem-leaves broadly oblong or 

 obovate; bracts broad, only the outer ones squarrose-reflexed. 



12. G. erecta. 

 Stems low, about 3 dm. high, usually several from the base; stem-leaves 



oblanceolate or oblong; all bracts squarrose. 13. G. subalpina. 



Heads discoid. 



Stem-leaves oval or obovate. 14. G. inornata. 



Stem-leaves oblanceolate or oblong. 



Outer bracts strongly recurved, the inner not squarrose. 15. G. fastigiata. 

 All bracts squarrose. 



Bracts long and loose, but not strongly recurved. 16. G. aphanactis. 

 Bracts short, strongly recurved-curled. 17. G. columbiana. 



1. G. platylepis Greene. Perennial; stem about 5 dm. high, glabrous; 

 leaves oblanceolate or oblong; involucres hemispheric, subtended by one or two 

 leafy bracts; bracts oblong, abruptly herbaceous-tipped, not viscid; ligules 

 broad, oblong, obtuse; pappus-bristles subulate, barbulate. Hills: Wyo. Sub- 

 mont. 



2. G. oregana A. Gray. Perennial; stem 3-10 dm. high, sparingly puberu- 

 lent or glabrous; basal leaves narrowly oblanceolate, entire or slightly denticu- 

 late, 1-2 dm. long, glabrous; stem-leaves lanceolate, oblong or oblanceolate; 

 involucre about 15 mm. high and 15-20 mm. broad; ligules numerous, 15-20 mm. 

 long; pappus-bristles 3-4 mm., smooth, curved. Dry grounds: B.C. Ida.- 

 Ore. Submont. Jl-Au. 



3. G. decumbens Greene. Perennial, with a cespitose caudex; stem 2-5 

 dm. high, more or less decumbent at the base; basal leaves oblanceolate, _obtuse, 

 serrate towards the summit; stem-leaves oblong, acute, entire or denticulate; 



