GENUS 108. THISTLE FAMILY. 557 
1. Centaurea Cyanus L. Blue-bottle. 
Corn Blue-bottle. Corn-flower. 
Fig. 4656. 
Cen'aurea Cyanus L. Sp. Pl. gt1. 1753. 
Annual, woolly, at least when young; stem\ 
leafy, slender, branched, 1°-23° high, the branches 
ascending. Leaves linear or linear-lanceolate, 
mucronate, 3-6’ long, the basal and lower ones 
mostly remotely dentate, the upper, or sometimes 
all of them, entire; heads 17-12’ broad, on long 
naked peduncles; involucre campanulate, its bracts 
greenish-yellow, or the inner with darker tips 
and margins, appressed, fimbriate with scarious 
teeth; flowers blue, purplish, pink or white, the 
marginal ones neutral with large radiant corolla- 
limbs; achenes slightly compressed, or 4-angled; 
pappus bristles unequal, nearly as long as the 
achene. 
In waste places, escaped from gardens, and in bal- 
last, Quebec to Ontario, western New York, Nebraska 
and Virginia. Witches’-bells or -thimbles, corn- 
centaury, corn-bottle or -binks. Brushes. Hurt-sickle. 
Blue-bonnets. Blaver. Blue poppy. Bachelor’s-but- 
tons. Bluecaps. Barbeau. French pink. July—Sept. 
2. Centaurea Jacea L. Brown or Rayed 
Knapweed. Fig. 4657. 
Centaurea Jacea L. Sp. Pl. 914. 1753. 
Perennial, 2° high or less. Leaves entire or 
denticulate, rarely lobed; heads 1’-14’ broad; in- 
volucre globular to ovoid, its bracts closely im- 
bricated, brown or with brown backs, the outer 
ones pale brown with fimbriate appendages, the 
middle ones lacerate, the inner entire or nearly 
so, dark brown; marginal flowers neutral with 
enlarged radiant corolla-limbs; achenes obscurely 
4-sided; pappus none, or a minute crown. 
In waste places, northern New York, Vermont and 
Massachusetts, and in ballast about eastern seaports. 
Also in British Columbia. Fugitive from Europe. 
June-Sept. 
3. Centaurea nigra L. Black Knapweed. 
Horse-knops. Hardheads. Centaury. 
Fig. 4658. 
Cen aurea nigra L. Sp. Pl. 911. 1753. 
Perennial, scabrous or pubescent; stem stiff, 
branched, 1°-2° high. Lower and basal leaves 
spatulate or oblong, acutish, entire, denticulate, \ 
dentate or lobed, not pinnatifid, 3’-6’ long, nar- 
rowed into long petioles; upper leaves oblong or 
lanceolate, sessile, or partly clasping, entire or 
nearly so; heads rarely 1’ broad, bracted by the 
small, uppermost leaves; involucre globose, its 
bracts lanceolate or ovate-lanceolate, closely im- 
bricated, tipped with brown fimbriate appendages, 
or the uppermost merely lacerate; flowers rose- 
purple, all perfect, the marginal ones usually not 
at all enlarged, or sometimes radiant; achenes 
slightly 4-sided ; pappus none, or a ring of minute 
scales. 
In waste places and fields, Newfoundland to On- 
tario, New Jersey and Pennsylvania. Naturalized 
from Europe. Among many other English names are 
jron-head or -weed, club-weed, matfelon, hurt-sickle, 
tassel, horse-knobs; crop-, knob-, bole- or button- 
weed; loggerheads, Jady’s-cushion, blue-tops, hard- 
weed, bullweed, sweeps, bachelor’s-buttons. July— 
Sept. 
