56 MIDDLESEX FLORA. 



*S. viscostis, L. 

 Lowell, waste ground (Dr. F. Nickerson) ; Aug.-Oct. Adv. from Eu. 

 "Coarser than the preceding, viscid-pubescent, strong-scented; 

 leaves once or twice pinnatifld ; heads rather larger, more peduncu- 

 late; involucre sparingly and slenderly bracteolate at base, its 

 bracts not black-tipped; rays with inconspicuous ligule; akenes 

 glabrous." Syn. Fl. N. A. 



S. aureus, L. Golden Ragwoet. 

 Common. May-June. 



S. aureus, L., var. obovatus, Torr. & Gray, Melrose (F. S. 

 Collins). 



S. aureus, L., var. Balsamitae, Torr. & Gray, Stoneham; 

 (Bigelow's Fl. Bost.) ; Woburn (C. E. Perkins). 



Centaurea, L. 



C. Gyanus, L. Bachelor's Button. Bluebottle. 

 Escaped from gardens. July-Aug. Int. from Eu. 



C. NIGRA, L. Knapweed. 

 Chelmsford (Dr. C. W. Swan) ; Acton (L. L. Dame) ; Billerica (C. 

 W. Jenks) ; and common for many years in the towns near Boston. 

 Foruis with white and pink flowers not uncommon; occasional 

 forms with marginal flowers much enlarged. Aug.-Sept. Nat. 

 from Eu. 



C. Jacea, L. 

 Spreading in a field in E. Lexington (Miss Eliza Wellington) . Adv. 

 from Eu. 



" Heads usually larger (than nigra) ; brownish appendages of the 

 involucral bracts merely lacerate ; marginal flowers neutral and with 

 enlarged palmate corollas, forming conspicuous false rays ; other- 

 wise like nigra." Syn. Fl. N. A. 



C. leucophcea, Jord. 

 What may be this species was collected at Westford, near the 

 woollen mills, by Dr. C. W. Swan. The plants are about a foot 

 high, with numerous pinnatifld radical leaves, and stem leaves 

 similar but smaller and less divided, the uppermost short and linear. 

 The heads are about the size of those of C. nigra, rose color, the 

 scales of the involucre conspicuously veined, with darker, ciliate tips. 



C. benedicta, L. (Cnious benedictus, L., Man.) Blessed Thistle. 

 Cambridge, waste-heap, a few plants, 1885 (Kev. Thos. Morong; 

 specimen in herb. of). Adv. from Eu. 



Cnicus, Tourn., L. 



C. LANCEOLATUS, HofFm. (Cirsium lauceolatum, Scop., Man.) Com- 

 mon Thistle. 

 Common. July-Sept. Nat. from Eu. 



