MIDDLESEX FLORA. 59 



C. fcetida, L. 



Westford, woollen-mill yard (Dr. C. W. Swan). Adv. from Eu. 

 " Stem erect, leafy, branching, hairy ; leaves hairy, runciuate- 

 pinnatifid, the uppermost lanceolate, deeply incised at the base; 

 peduncles drooping before flowering; beaks of the marginal 

 achenia shorter than the involucre, those of the interior longer ; the 

 entire involucre downy and villous; hairs simple and glandular; 

 bracts of the involucre lanceolate, acute." Koch, Syn. Fl. Germ. 



PRENANTHES, Vaill. 

 P. alba, L. (Nabalus albus, Hook., Man.) WHITE LETTUCE. 



Common. Aug.-Sept. 

 P. altissima, L. (Nabalus altissimus, Hook., Man.) TALL WHITE 



LETTUCE. 



Common. Aug.-Sept. 

 P. serpentaria, Pursh. (Nabalus Fraseri, DC., Man.) LION'S 



FOOT. GALL-OF-THE-EARTH. 



Tewksbury and Winchester (Dr. C. W. Swan) ; Belmont and 



Arlington (C. E. Perkins) ; Medford (Wm. Boott) ; Waltham List; 



Concord (Minot Pratt). Not common. Aug.-Sept. 



TARAXACUM, Hall. 

 T. of f icinale, Weber. (T. Dens-leonis, Desf ., Man.) DANDELION. 



Very common. Apr.-July. 



LACTUCA, Tourn. 

 L. Canadensis, L. WILD LETTUCE. 



Common. Aug.-Sept. 

 L. integrifolia, Bigel. (L. Canadensis, var. iiitegrifolia, Torr. & 



Gray, Man.) 



Tewksbury (Dr. C. W. Swan) ; Maiden and Melrose (F. S. Collins). 



Not very common. Aug.-Sept. 

 L. hirsuta, Muhl. (L. Canadensis, var. sanguinea, Torr. & Gray, 



Man.) 



Lowell (Dr. C. W. Swan) ; Maiden, Melrose, et al., not rare (F. S. 



Collins). Aug.-Sept. 

 L. SCARIOLA, L. PRICKLY LETTUCE. 



Maiden (F. S. Collins); Sonierville (C. E. Perkins); Cambridge 



(Wm. Boott). Not common. Aug. Nat. from Eu. 

 L. leucophaea, Gray. (Mulgedium leucophseum, DC., Man.) 



BLUE LETTUCE. 



Widely distributed; not uncommon. Aug.-Sept. 



SONCHUS, L. 



S- OLERACEUS, L. SOW- THISTLE. 



Maiden, Somerville, Westford, Framingham, et al. Not uncommon. 

 Nat. from Eu. 



