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Poison Ivy Poison Sumac Sti-pa spartea (skin irritant for animals only)Porcupine Grass C. Causing Hay Fever. East of the iooth meridian in theUnited States ninety per cent, of the cases of hay fever are caused bythe common ragweed {Ambrosia elatior) while in the Rocky Mountainand Pacific states the sage brush {Artemisia) replaces the ragweed asthe most common hay fever weed. The so-called "rose fever" fromwhich many people suffer each year is not caused by roses at allbut by pollen from several different grasses. There are a number ofcommonly planted ornamental plants which possess hay-fever produc-ing characteristics, as follows: |
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