Letters Grindelia squarrosa See allHide authors and affiliations Science 23 Sep 1887:Vol. ns-10, Issue 242, pp. 152DOI: 10.1126/science.ns-10.242.152-a L. N. JohnsonFind this author on Google Scholar Find this author on PubMed Search for this author on this site Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.