B. P. 1.—669. 
AMERICAN MEDICINAL LEAVES AND HERBS. 
INTRODUCTION. 
Less difficulty will be encountered in the collection of leaves and 
herbs than in the case of other portions of plants, for not only is 
recognition easier, since, especially in the matter of herbs, these 
parts are usually gathered at a time when the plants are in flower, 
but the labor is less arduous, for there are no roots to dig or barks 
to peel. 
Of the three dozen medicinal plants mentioned in this bulletin, 15 
are recognized as official in the Eighth Decennial Revision of the 
United States Pharmacopeia. This is more than half of all the 
leaves and herbs included in the Pharmacopeeia. 
Among the plants included in this bulletin are peppermint and 
spearmint, which are found not only in the wild state but the culti- 
vation of which for the distillation of the oil constitutes an impor- 
tant American industry. Especially is this true of peppermint, 
thousands of acres being devoted to the cultivation of this plant, 
principally in the States of Michigan and New York. A number of 
other plants mentioned in this paper furnish useful oils, such as oil 
of wintergreen, pennyroyal, fleabane, tansy, wormwood, and fire- 
weed. 
As in the case of other bulletins of this series, an effort has been 
made to include in it only such plants as seem most in demand, lack 
of space forbidding a consideration of others which are or have been 
used to a more limited extent. With two or three exceptions the 
illustrations have been reproduced from photographs taken from 
nature by Mr. C. L. Lochman. 
COLLECTION OF LEAVES AND HERBS. 
Leaves are usually collected when they have attained full develop- 
ment and may be obtained by cutting off the entire plant and strip- 
ping the leaves from the stem, using a scythe to mow the plants 
where they occur in sufficient abundance to warrant this, or the 
leaves may be picked from the plants as they grow in the field. 
Whenever the plants are cut down in quantity they must be care- 
fully looked over afterwards for the purpose of sorting out such 
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