1204 CARDUACEAE 
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 diffüsa 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 Caroiina 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 latisquàma 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 
poer lue ligules: achenes obovate, 1.5 mm. long: pappus-bristles nearly as long as the 
achene. 
In river valleys, Minnesota to Kansas and Arkansas. Summer and fall. 
4. Boltonia decürrens (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. bellidifolia. 
Perennial: foliage hispid : leaf-blades spinulose-serrulate. 2. K. effusa. 
1. Keerlia bellidifólia 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 effüsa 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 em. 
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, inconspieuous. 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. 
