American tobacco belongs almost exclusively 
to that group of this family which comprise 
the genus Nicotiana. Of this genus there are 
_ about 50 separate species, one of which, Nico- 
tiana Tabacum, supplies almost all the tobacco 
of commerce. Plants of this species grow from 
2 feet to 9 feet in height; they have numerous 
_ Wide-spreading leaves sometimes as much as 
3 feet in length; these leaves may be oval, 
oblong, pointed, or lanceolate in shape, and 
are generally of a pale green color when young; 
they are arranged alternately in a spiral on 
the stem; the root is large and fibrous; the 
stem is erect, round and viscid, branching near 
the top. The alternate arrangement of the 
leaves on the stalk, succeeding each other 
spirally, so that the 9th overhangs the Ist, the 
10th the 2nd, and so on, is very characteristic. 
The distance on the stalk between the leaves is 
about 2 inches. Flowers are in large clusters, 
with corollas of rose color, or white tinged with 
pink. The leaves and stalks are covered with 
soft downy hair. The plant is perennial but 
crops are usually raised from seed. 
Of this species (N. Tabacum) there are prob- 
ably more than 100 varieties grown in the U. S. 
alone. Some of the best known will be described 
later. 
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