42 
DESCRIPTION OF MEDICINAL PLANTS. 
ceptacle flat, membranaceous chaffy, pappus none. Rays 10- 
15 linear oblong, much longer than the inner scales of the 
involucre, yellow; achenes strongly striate. At the foot of 
hills, where rich soil accumulates. The plant exhales a pecu- 
liar resinous odor. The heavy root is collected in autumn. 
Erechtites hieracifolia, Raf. Fire-weed. A tall, coarse annual; 
siem-grooved 2-8° high, the alternate simple leaves lanceo- 
late or oblong, acute, cut-toothed, sessile, the upper auricled 
at base. Heads many-flowered ; the flowers all tubular and 
fertile ; the marginal pistillate, with a slender corolla. Scales 
of the cylindrical involucre in a single row, linear, acute, 
with a few small bractlets at the base. Receptacle naked. 
Achenes oblong, tapering at the end ; pappus copious, of very 
fine and white soft hairs. The whitish flowers in paniculate- 
corymbed heads. Everywhere in moist woods, always ap- 
pearing in recent clearings, where the ground has been burned 
over. The leaves collected in summer. 
Arctium Lappa, L. Burdock. Coarse biennial weed, with large 
unarmed and petioled leaves; leaves roundish or ovate and 
mostly cordate, or lanceolate with cuneate base, smooth 
above, somewhat floccose-tomentose beneath, mostly sinuate- 
denticulate. Heads many-flowered ; flowers all tubular, per- 
fect and similar. Involucre globular; the imbricated scales 
coriaceous and appressed at the base, attenuate to long stiff 
points with hooked tips. Receptacle bristly. Achenes oblong, 
flattened, wrinkled transversely ; pappus short, of numerous 
rough bristles, separate and deciduous. Its flowers are purple 
and appear from July-October. It has spread over the whole 
world, and is a troublesome weed to the agriculturist, always 
ready to make its appearance in neglected ground, growing 
rapidly, and, with its large, spreading leaves checking all 
other vegetation. For medicinal purposes the leaves, root 
and seeds are collected. 
Silybum Marianum, Gsert. The Milk Thistle. Robust herb- 
aceous plant, belonging to the thistles, among which it is 
distinguished by having the filaments united and the pap- 
