rg 
Stem with long, prickly wings running down it from- 
the insertions of the leave’: bracts of the flower- | 
heads (except in C. palustris) with fine, prickly 
points. . 
Pappus, or ‘“thistle-down”’ (see page 36) with the | Me, 
points, hardly prickly ; heads oval, crowded in 
groups. C. palus'tris. 
Bracts widely spreading, with slender, spinous 
points ; heads large, roundish-oval. 
C. lanceola'tus. Spear Thistle. 
Pappus hairs not feathered. 
Flower-heads oval or cylindric, small, their inner- 
bracts longer than the florets. J 
C. pycnoceph/alus. 
~Heads round, or florets much exceeding bracts. 
Heads large, drooping, on curved stalks which are- 
G not prickly near the head; bracts oe 
Ce Bey 
hairs feathered. 
en scarcely spreading, except at the short, widish- 
— a A 
with a strong, distinct mid-rib. 
C. nu'tans. Musk Thistle. 
~Prickly wings running right up to the head. 
Heads often clustered, under 1 inch wide; 
3 bracts with a distinct mid-rib. 
| C. acanthoi'des. Welted Thistle. 
~Heads not clustered, over 1 inch wide; bracts- 
solid in the upper part, without any distinct 
mid-rib. | 
O. Acan’thium. Scotch Thistle 
“Stem without prickly wings; (pappus not feathered). 
-Heads large, globular, very woolly; bracts with long, 
fine, spreading points, with reddish hairs near | 
their tips. 
| 
C. erioph’orus./ 
~Heads oval; bracts with short, widish points. 
Heads several, in clusters; corolla cloven down to- 
( where it narrows into a.tube. | 
| C. arven’sis field Thistle. 
\Heads solitary or few, not clustered. 
‘an eaves not deeply divided; heads usually solitary,- 
| rarely two. | 
C. praten’sis.~ 
Leaves mostly deeply divided ; heads usually two,- 
three, or four. | 
) C. tubero’sus.~ 
