144 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
The number of cases of dermatitis from R. diver siloha is influenced, not 
only by the condition of the plant, but also by those conditions which tend 
to make individuals come in contact with it or with substances coated with 
its poisonous sap. The clinical statistics, therefore, do not constitute a 
true index of the virulency of the plant, since the total number of persons 
exposed is not known. The number of exposed persons in all probability 
varies at different times of the year, according to the weather conditions, 
state of other vegetation, individual freedom, etc. 
Many attractive wild flowers are found in the same locality with R. 
diversiloha shrubs, such as Clarkias, Godetias, Collinsias, Brodiaeas, and 
larkspurs (Parsons, 47). John Muir (43) "oftentimes found a curious 
twining lily {Stropholieion Calif ornicum) climbing its branches." The 
desire to gather spring wild flowers is often greater than the fear of Rhus 
diversiloha. Circumstances thus combine to bring a person in contact with 
the plant at the time when it is capable of doing the most harm. 
LITERATURE CITED 
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11. — ■ — ■ — ■ — ■ — ■ — -. The Philadelphia Polyclinic 7: 20. 1898. 
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15. Engler, A., and Prantl, K. Die nattirlichen Pfianzenfamilien HI, 5: 168. 1897. 
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