424 Karl M. Wiegand and Arthur J. Eames 



1. A. Lappa L. Great Burdock. 



A weed in rich soil and in clay, by roadsides and in waste places ; locally common. 

 Aug.-Sept. 20. 



Observed chiefly about Ithaca, very rarely elsewhere as at Caroline Center. 



N. E. and the East Central States, possibly farther westw. ; rare in sandy regions. 

 Naturalized from Eu. 



2. A. minus (Hill) Bernh. (Including A. ncmorosum Lej.) Smaller Burdock. 

 A weed in situations similar to the preceding or perhaps in more sterile soils, often 



in clay ; very common, and generally distributed. Aug.-Sept. 

 Widely distributed in N. A. westw. to Colo. Naturalized from Eu. 



2a. A. minus (Hill) Bernh., var. corymbosum Wiegand. (See Rhodora 26: 5. 1924.) 



In situations similar to the preceding ; not quite so common. 



Range same as that of the typical form, or possibly more eastern. Naturalized 

 from Eu. 



The various European treatments of Arctium are not in accord as to the extent 

 of segregation of A. minus, or on what characters the segregation should be based. 

 Following what seemed to be European practice, Fernald and Wiegand (Rhodora 

 12:43, 1910) segregated A. nemorosum Lej. on the basis of larger heads, more 

 spreading involucre, and the dark ground color of the achene. A. H. Evans 

 (Journ. Bot. 51 : 113, 1913) separates A. vulgaris (Hill) Evans on the larger corymbose 

 heads and spreading involucre, and refers A. nemorosum Lej. to A. minus. Hill's 

 plate of Lappa vulgaris, however, has more the appearance of A. Lappa. A study 

 of the material about Ithaca and elsewhere seems to show that besides A. Lappa 

 there is but one species, A. minus (Hill) Bernh. The heads vary somewhat in size, 

 the larger heads having less appressed involucres ; but the seeds, the florets, the in- 

 volucres, and the leaves are practically identical. On the other hand, good characters 

 separate this species from A. Lappa L. 



32. Echinops L. 

 1. E. Ritro L. (See Bailey, Man. Cult. PL, p. 789. 1924.) Globe Thistle. 



"Caroline Center, escaped from cult, and spreading rather freely, along a brook. 

 (F. T. Wilson, 1885.)" (£>., and in C. U. Herb.) ; near Lake Como, 1923 (G. B. 

 & L. N. Upton). 



Introduced from Eu. 



33. Carduus (Tourn.) L. 

 1. C. nutans L. Musk Thistle. • 



A weed in dry gravelly pastures ; rare. July. 



Between the C. U. barns and Forest Home, over an area of many square feet, 

 1913 (£. Dean & A. J. E.) ; Dryden, 1912 {Miss L. J. Sweetland). Of recent 

 introduction, but well established. 



Occasional in the Atlantic States, but apparently rare or absent on acid soils. 

 Naturalized from Eurasia. 



34. Cirsium (Tourn.) Mill. 



a. Heads large, 3-9 cm. in diam. ; plant not stolonif erous. 



b. Outer and inner involucral bracts spine-tipped ; leaves strongly arachnoid beneath, 

 decurrent. 1. C. lanceolatum 



b. Outer bracts spine-tipped, inner bracts soft and spineless ; leaves not decurrent 

 (see also 3d b). 



