MEDICINAL PLANTS. 161 



effective weapons, and they should be used to prevent, as far as 

 possible, the development of seeds. 



V. Medicinal Plants. 



This is by no means the least interesting part of the flora. 

 The products of more than forty native species are recognized 

 as official by the U. S. Pharmacopeia. In addition to these, 

 many species are used as substitutes, or as home remedies. 

 Some of the official species are not found in sufficient quantity 

 to be of commercial value, but their occurrence in the county is 

 of interest. Various parts of plants contribute the official pro- 

 duct, and the best season of the year for collecting the materials 

 will vary with the part used. It may be stated as a general rule 

 that rhizomes and roots should be collected in late summer or 

 early autumn; the bark of Ulmus in early spring, and other 

 barks (of both root and stem) in spring or autumn; the herbs 

 and leaves are usually best just before flowering has commenced; 

 the flowering tops when the first flowers are about to fruit; the 

 flowers just after opening; and the fruits when mature. The 

 distribution in the county, and the habits of the species dis- 

 cussed in this connection are given in the annotated list. The 

 species are here grouped according to the part of the plant 

 yielding the official drug, the official name preceding the name 

 of the plant, which is given in parenthesis. 



1. The herb (leaves and young stems). — Oil of Erigeron 

 (Leptilon canadense), Pulsatilla (Pulsatilla hirsutissima) and 

 Scutellaria (Scutellaria lateriflora) . 



2. Flowering tops. — Eupatorium (Eupatorium perfolia- 

 tum), Hedeoma (Hedeoma pulegeoides) and Lobelia (Lobelia 

 inflata). 



3. Leaves. — Chimaphila (Chimaphila umbellata), and Rhus 

 Toxicodendron (Rhus radicans), the latter fresh. 



4. Floivers. — Sambucus (Sambucus canadensis). 



5. Fruit. — Rhus Glabra (Rhus glabra), Humulus (Humulus 

 lupidus), Oil of Juniper (Juniperus communis) and Raspberry 

 (Rubus occidentalis and strigosus). 



6. Seeds. — Sinapis Nigra (Brassica nigra). 



7. Bark of stem. — Hamamelis Bark (Hamamelis virgini- 

 ana). Canada Balsam (from Abies balsamea), Oil of Betula 



