260 POPULAR FIELD BOTANY. 
scales of the receptacle are admirably adapted. These heads 
are fixed round the circumference of a large broad wheel, 
which is made to revolve, while the cloth is held against 
them. Its use is to draw out the ends of the wool from the 
manufactured cloth, so as to bring a regular nap upon the 
surface free from twistings and knottings, and to comb off 
the coarse and loose parts of the wool.” All mechanical 
contrivances hitherto invented, tear the cloth into holes 
during this progress. The fud/orum is scarcely found wild, 
and Dipsacus pilosus, the third species, is not common. It 
is smaller in size than the sylvestris, and the heads of flowers 
are round and hairy, the scales straight. 
TETRANDRIA. MONOGYNIA. 
CoROLLIFLORZ. DIPSACE. 
KNAUTIA. (Kyavtta.) 
Generic Character. Jnvolucre (or leaves under the head of 
flowers) many-leaved. Calyx double, exterior minute, interior 
cup-shaped. Receptacle hairy. 
Kwnavtta arvensis. Feld Knautia. This plant has its 
flowers in heads also, with an involucre of many leaves under 
