MIDDLESEX FLORA. 57 



C. altissimus, Willd., var. discolor. Gray. (Cirsium discolor, 

 Sprang., Man.) 

 Maiden (F. S. Collins). Scarce. Aug .-Sept. 



-C. muticus, Pursh. (Cirsium muticum, Michx., Man.) Swamp 

 Thistle. 

 Not very common. Aug.-Sept. 



C pumilus, Torr. (Cirsium pumilum, Sprang., Man.) Pasttjre 

 Thistle. 

 Common'; a white flowered form occasional. July-Aug. 



C. horridulus, Pursh. (Cirsium horridulum,Michx., Man.) Yel- 

 low Thistle. 



Medford and Everett (P. S. Collins). Rather scarce, and found 

 only near salt water. June-July. 



C. ARVENSis, Hoffm. (Cirsiumarvense, Scop., Man,) Canada This- 

 tle. 



Very common ; a white flowered form not uncommon. July-Sept. 

 Nat. from Eu. 



Onopordon, Vaill. 



O. ACANTHitjM, L. Cotton Thistle. 



Watertown (Wm. Boott) ; Tewksbury (C. J. Sprague) ; Chelms- 

 ford (Dr. C W. Swan) ; Somerville (C. E. Perkins) ; Concord 

 (Mlnot Pratt). Rare. July. Nat. from Bu. 



Arctium, L. 



A. Lappa, L., var. majus, Gray. (Lappa officinalis, AU., var. major, 



Man.) Larger Burdock. 



"Westford, near woollen' mill (Dr. C. W. Swan) ; Maiden (P. S. 



Collins). Aug.-Sept. Adv. from Eu. 

 A. Lappa, L., var. tomentosum. Gray. 



Cambridge, waste-heap (Rev. Thos. Morong). Adv. from Eu. 

 A. Lappa, L., var. minus, Gray. Burdock. 



Very common ; a form with white flowers occasional ; also a form 



with laciniate leaves. Nat. from Eu. 



Lampsana, Toum. 



L. communis, L. Nipplewort. 

 Medford (C. E. Perkins) ; Newton (C. J. Sprague). Nat. from Eu. 



CiCHORiUM, Toum. 



C. iNTYBus, L. Succory. Chicory. 

 Common, especially near Boston. July-Sept. Nat. from Eu. 



Krigia, Schreb. 



K. Virginica, Willd. Dwarf Dandelion. 

 Common. May-June. 



