Chicory Family. 99 



petioles, upper clasping: thyrsus 4-.M) inches long; involucre hirsute; flowers 

 purplish. Low prairies; August-September; frequent; Emmet, Hancock, 

 Floyd, and Lyon counties; reportedj f rom Fayette and Story counties. ( A", va- 

 cemosus ( Mx. ) DC ) 



P. crepidinea Ms. Stem 4-8 feet high, branched above;, glabrous or mi- 

 nutely pubescent; leaves ample, ovate, triangular-ovate or hastate, toothed, 

 wing-petioled; heads nodding, in loose clusters, corymbosely-paniculate, invo- 

 lucre hirsute; flowers cream-color. Woods; August-September; rare; Johnson 

 county. ( A', crepldlnenx ( Mx...) DC. ) 



* * Bnicts of the liiwliirre ylnltrotix or spttrintjly hirsute. 



P. alba L. Stem 2-4 feet high, smooth, purplish, corymbosely-paniculate 

 above; leaves angulate or deltoid-hastate, sinuate toothed, on long slender 

 margined petioles; heads nodding, involucral scales about s, purplish; paprus 

 reddish-brown. Upland woods; August-September; frequent; Winneshiek; 

 Clayton. Floyd. Jackson, Lee, and Winnebago counties; reported from Fay- 

 ette, Scott, Muscatine, Story, and Emmet counties.. , . 



LYGODESMIA D. Don.. Perennials, with rush-like stems, I'neni'-sub- 

 ulate leaves, and long peduncled rose colored' flowers. Involucre cylindri- 

 cal, elongated. Pappus whitish, soft, copious. Achenes striate, terete. 



L. juncea (Pursh) D. Pon. Stein about ods foot high, much branched, 

 striate, from a deep-rooted base, nearly leafless; leaves small, lance-linear, 

 the upper minute, subulate; heads 5-flowered; involucre about a ha If inch high. 

 Fields and waste places: June-August; common in western Iowa; Emmet, 

 Lyon, Shelby, Fremont, and Dickinson counties; reported from Sioux, Wood- 

 bury, Harrison. Monona, and Ida counties. 



TROXIMON Nutt. Perennials, with tufted root leaves, and simple scapes, 

 bearing a -solitary head of yellow flowers. Involucre camparuilnte: scales 

 lanceolate or ovate, in 2 or 3 rows, pointed. Pappus white, copious, capillary. 

 Achenes linear-obloug. about 10-ribbed, beakless. 



T. cuspidatum Pursh. SCape 4-10 inches high, from a thick fusiform 

 root; leaves elongated linear-laneeolate, tapering both ways, woolly-mar- 

 gined; head- solitary, large:, many-flowered. Prairies; April-May; infrequent; 

 Shelby, Emhiet, Calhoun, Marshall,- Johnson, and Lyon counties?, reported 

 from Fayette, Scqtt.and Story eounti§s.:(;Vi/(/iocai(us cusphlntn (Pursh) Greene). 



TARAXACUM Haller. Steraless perennials, with lyrate-pinnatifid root- 

 leaves, and yellow flowers. Heads solitary, many-flowered. Involucre dou- 

 ble; the outer of short small scales, reflexed; the inner linear, much -longer, 

 in one row, appressed. Receptacle naked. ■- Pappus white, capillary, copious, 



T. officinale Weber. Common Dandelion. Scapes 4-1S inches high, hollow, 

 from a thick descending root. " Involucre reflexed at maturity of the fruit, 

 exposing the achengs and globular head, of pappus to the wind. Achenes 

 ovate-oblong to fusiform, apex prolonged into a slender beak which is 2 or 3 

 times the length of the achene. Fields and waste places; mostly April and 

 May but many appearing until the close of September; common. 



LACTUCA L. Ljjttcck. Annual, biennial, or perennial herbs, with, leafy 

 stems, panicled heads, and yellow, blue, or white flowers. Heads- few- to 

 many-flowere; 1 . Rays truncate, 5-toothed. Involucre glabrous, cylindrical, 

 imbricated in two or more unequal rows. Pappus white, rarely tawny, soft, 

 capillary,, copious, Achenes flattened parallel with the scales, abruptly 

 beaked, 3-5-ribbed. 



* Leave* spinu-iiwyincd; the midribs spiny or hispid; powers yellow. 



