Right Answer:
You can tell this is Perennial sowthistle because It has large leaves at its base which have soft spines on their margins.  The inflorescence is very pronounced and contains easily identifiable, deep yellow flowers.  If the stems of this species are cut open they will exude a milky white sap much like that of milkweed. The seeds are brownish, slender and will be somewhat flattened.  Each seed will have 5-7 ridges running its length.  Quite often the seeds will be found with a small tuft of hair attached.
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