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326. Babcock, E. B. "The genus Crepis ." Univ. Calif. Pub. Botan. 21-22: 1-1030. 1947. 



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332. Steyermark, J. A. "A monograph of the North American species of the genus Grindelia." Ann. Mo. 

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335. Weber, William A. "The genus Helianthella (Compositae) . " Amer. Midi. Natur. 48: 1-35. 1952. 



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339. Everly, M. L. "A taxonomic study of the genus Perityle and related genera." Contrib. Dudly Herb. 3: 

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340. Shinners, Lloyd H., "Synopsis of the genus Eustoma (Gentianaceae). " Southeastern Naturalist 2: 38 -43 . 

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341. Shinners, L. H. "Revision of the genus Leucelene Greene." Wrightia 1: 82-89. 1946. 



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343. Williams, E. VV. "The genus Malacothrix (Compositae)." Amer. Midi. Natur. 58: 494-512. 1957. 



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346. Anderson, Loran C . , "Studies on Petradoria Compositae: Anatomy, Cytology, Taxonomy." Transactions 

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347. Cronquist, A. "A review of the genus Psilocarphus . " Res. Studies State Coll. Wash. 18:71-89. 1950. 



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