The Flora of the Cayuga Lake Basin 425 



c. Leaves white-tomentose beneath, the divisions few, rather long and narrow ; 



heads medium-sized. 2. C. discolor 



c. Leaves arachnoid or green beneath, the divisions many, short and broad ; 

 heads very large (4-8 cm. broad). 3. C. pumilum 



b. Outer and inner bracts all spineless, merely mucronate ; leaves arachnoid beneath, 

 mostly with rather deep and narrow divisions, not decurrent. 



4. C. muticum 

 a. Heads small, 2.5 cm. in diam. or less ; involucral bracts spineless or the outer ones 

 with short prickly points ; leaves not decurrent, scarcely woolly, with many short 

 broad lobes; plant strongly stoloniferous. 5. C. arvense 



1. C. LANCEOLATUM (L.) Hill. BULL THISTLE. 



A weed in dry pastures, fields, and waste places, mostly in rich gravelly non- 

 acid soils ; common, but never abundant. July 15-Sept. 



Scarce on the sterile, more residual, soils of the higher hills of the basin, and in 

 the sands n. of the lake. 



Newf . to Oreg., southw. to Fla., Nebr., and Calif. ; less frequent on the Atlantic 

 Coastal Plain. Naturalized from Eurasia. 



2. C. discolor (Muhl.) Spreng. (Cnicus altissimus, var. discolor, of Cayuga Fl.) 

 On banks in rich gravelly soils ; scarce. Aug. 



Negundo Woods (D.) ; University Grove, formerly (D.) ; Indian Spring marsh 

 (D.) ; Myers Point, and occasionally along the lake shore to Levanna and Lockwood 

 Flats (£>.!) ; Salmon Creek. 



N. B. to S. Dak., southw. to Ga., Mo., and Nebr. In the coastal region the plant 

 is more abundant close to the ocean, possibly in saline soils. 



3. C. pumilum (Nutt.) Spreng. Pasture Thistle. 



Fields and pastures, usually in dry sandy or gravelly acid soils, rarely in more 

 alkaline gravels ; frequent. July-Sept. 



Confined chiefly to the hills s. w., s., and s. e. of Ithaca: n. of Spencer Lake, and 

 hill pasture n. w. of North Spencer ; e. of South Pinnacle (D.) and n. of North 

 Pinnacle, Caroline; s. e. of Brookton; South Hill (D. !) ; near Coy Glen; n. of Fall 

 Creek (D. !) ; Ringwood; and elsewhere. 



Me. to N. Y., southw. to S. C. and W. Va., including the Coastal Plain. 



4. C. muticum Michx. Swamp Thistle. 



Swampy and springy places in mucky soil, in both calcareous and noncalcareous 

 situations ; frequent, and generally distributed. Aug.-Sept. 



Newf. to Sask., southw. to Fla. and Tex., including the Coastal Plain. 



5. C. arvense (L.) Scop. Canada Thistle. 



A weed in fields, cultivated grounds, and waste places, especially in the richer, 

 heavier soils ; very common, and generally distributed. July-Oct. 



Newf. and B. C., southw. to Va., Nebr., and Utah. Naturalized from Eu. 

 The white-flowered form is occasional. 



35. Onopordum (Vaill.) L. 

 1. O. Acanthium L. Scotch Thistle. 



Roadsides and waste places ; occasional. July-Aug. 



Near Percy Field; C. U. campus; a bad weed in a dry gravelly pasture V/2 miles 

 n. of Slaterville. 



N. B. and N. S. to Ont. and Mich., southw. to N. J. Introduced from Eurasia. 



