120 FLORA OF MOUNT DESERT. ERECTITES, Raf. FIREWEED. 306 E. hieracifolia (L.), Raf. Wood clearings, especially in recently burned ground; common. ARCTIUM, L. BURDOCK. 307 A. LAPPA, L. [illegible] Common in waste places, especially about old dwellings. B. Pdx. Naturalized from Europe. V. Carl. Place Q.S.W. CNICUS, L. THISTLE. 308 C. LANCEOLATUS (L.), Hoffm. COMMON THISTLE. Pence 4B Mt. Pastures, fields and roadsides; common. Naturalized from C. Stg. B. W. Europe. Everywhere A. R. B. V. Carl. BR. D. GR. S. T 309 C. ARVENSIS (L.), Hoffm. CANADA THISTLE. Pence. D 4B Mt. T Pastures, fields, and roadsides; too common. Naturalized C. B. Pdx. from Europe. do. V. Carl+ BR. GR. RC RIA— Q. S.W. T. 310 Forma ALBIFLORUS. Flowers pure white. Southwest Harbor (Rand);—Seal Har- bor (Wm. C. Lane). CENTAUREA, L. STAR THISTLE. 311 C. CYANUS, L. BLUEBOTTLE. BACHELOR'S BUTTON. Occasionally escaped from cultivation to roadsides and waste places, Southwest Harbor, etc. (Rand, Annie S. Downs). Pdx. S. Carl+ ARNOSERIS, Gærtm. LAMB'S SUCCORY. A small, annual, scapigerous herb; juice milky; leaves all radical; heads few, small; peduncles clavate, fistular; involu- cral bracts in one series, many, after flowering arching over the fruit; receptacle flat, naked, pitted; corollas all ligulate, yellow; anther cells not tailed; upper part of style and its short obtuse arms hairy; fruit obpyramidal, furrowed and ribbed, not beaked, crowned by a coriaceous angular ring.