1204 CAKDUACEAE 



Bracts of the involucre broadest below the middle, acute. 2. B. asteroides. 



Bracts of the involucre broadest above the middle, obtuse or mucronulate. 3. B. latisquama. 



b. Leaf-blades decurrent on the stem as broad wings. 4. B. decurrens. 



1. Boltonia diffusa Ell. Stems slender, 1-2 m. tall, much-branched : leaf -blades 

 linear to linear-subulate, or broader near the base of the stem, 2.5-8 cm. long, acute : invo- 

 lucres 2-2.5 mm. high ; bracts numerous, linear or nearly so, acute : disk about 4 mm. 

 broad : ray-flowers numerous, with white ligules : achenes barely 1.5 mm. long. 



In low grounds, South Carolina and Illinois, south to Florida and Texas. Fall. 



2. Boltonia asteroides L'Her. Stems 1-2 m. tall, branching above : leaf -blades 

 linear, oblong or slightly broadest above the middle, 3-12 cm. long, acute, sessile : invo- 

 lucres 2.5-3 mm. high; bracts acute, broadest below the middle : disk 6-12 mm. broad : 

 ray-flowers numerous, with white or pale ligules : achenes fully 1.5 mm. long. 



In low grounds and along streams, New Jersey to Minnesota, south to Florida, Louisiana and 

 Nebraska. Summer and fall. 



3. Boltonia latisquama A. Gray. Stems much branched, 1-2 m. tall : leaf-blades 

 linear or nearly so, 2-10 cm. long, acute, sessile : involucres about 4 mm. high ; bracts 

 oblong to rhomboidal above the middle, obtuse or mucronate : ray-flowers numerous, with 

 violet-blue ligules : achenes obovate, 1.5mm. long: pappus-bristles nearly as long as the 

 achene. 



In river valleys, Minnesota to Kansas and Arkansas. Summer and fall. 



4. Boltonia decurrens (T. & G.) Wood. Similar to B. latisquama in habit, but 

 stouter and taller. Stem more or less branched, conspicuously winged by the decurrent 

 leaf -blades, glabrous or nearly so : leaf-blades spatulate to narrowly oblong or linear-oblong, 

 5-15 cm. long, obtuse or acutish, undulate, sessile and decurrent: involucres 3-3.5 mm. 

 high ; bracts linear-spatulate to linear, acute or acuminate : ray-flowers numerous, with 

 violet or pale ligules : achenes cuneate, about 2 mm. long : pappus-bristles somewhat 

 shorter than the achene. 



In low grounds, Illinois to Missouri and Arkansas. Summer and fall. 



44. KEERLIA A. Gray. 



Annual or perennial caulescent pubescent herbs. Leaves alternate : blades broadest 

 above the middle or oblong to linear, entire or serrulate. Heads radiate, few, slender- 

 peduncled. Involucres narrow, few-flowered : bracts thin, scarious-margined, in few series, 

 pointed. Receptacle flat. Ray-flowers 5-15, pistillate. Disk-flowers several, perfect. 

 Stigmas with short or long appendages. Achenes flattened, 2-3-nerved, those of the disk 

 mostly imperfect. Pappus a crown-like border sometimes evanescent. 



Annual : foliage minutely and somewhat scabro-pubescent : leaf-blades ciliate. 1. K. beUidifolia. 



Perennial : foliage hispid : leaf-blades spinulose-serrulate. 2. K. effusn. 



1. Keerlia. bellidifolia Gray & Engelm. Annual, minutely pubescent. Stems 1-2 

 dm. tall, sometimes diffusely branched : leaf -blades spatulate below to linear above, 1-3 

 cm. long, acute or acuminate, entire : involucres narrowly campanulate, 2.5-3 mm. high ; 

 bracts oblong-lanceolate to linear-oblong, cuspidate, scarious-margined : ray-flowers 6-15 ; 

 ligules blue : achenes oblong-clavate, 2 mm. long, slightly flattened. 



In moist soil, Texas. Spring and summer. 



2. Keerlia efifusa A. Gray. Perennial, hispid. Stems 3-7 dm. tall, simple below, 

 effusely branched above, the branches usually filiform : leaf-blades oblong to ovate, 1-3 cm. 

 long, acute or cuspidate, revolute, sessile and partly clasping : involucres oblong, 4 mm. 

 high ; bracts oblong-ovate to narrowly oblong, cuspidate, scarious-margined : ray-flowers 

 4-5; ligules white, narrowly oblong : achenes obovoid, 1-1.5 mm. long, flattish, the mar- 

 gins with 1 or 2 nerves. 



On hillsides, Texas. Spring and summer. 



45. THUROVIA Rose. 



Low annual herbs, with spreading branches, and glabrous. Leaves alternate : blades 

 narrow, inconspicuous. Heads mostly solitary and sessile in the axils of the leaves, dis- 

 coid, few-flowered. Involucres somewhat distended in age : bracts in 2 series, usually 8, 

 those of the inner series fewer than those of the outer. Flowers perfect, fruit producing. 

 Corollas funnelform at the throat, 5-lobed. Filaments not appendaged. Stigmas short, 

 with slender appendages. Achenes turbinate, silky, nerveless. Pappus of about 10 acu- 

 minate scales. 



