Genus 82. 



THISTLE FAMILY 



2. Tetraneuris stenophylla Rydb. Narrow- 

 leaved Tetraneuris. Fig. 4538. 



Tetraneuris stenophylla Rydb. Bull. Torr. Club 33: 155. 

 1906. 



Perennial with a branched caudex, the branches 

 often 3i' long, the upper portion covered with the 

 scarious bases of old leaves. Bases of the leaves 

 dilated, sparingly silky-villous ; blades narrowly lin- 

 ear, l'-lf long, about 1" wide, glabrous, conspicu- 

 ously punctate ; scape 2-4' high, minutely strigose ; 

 involucre S"~7" wide; bracts oval or oblong-acutish ; 

 rays about 5" long and 2" wide. 



In dry soil, Kansas to Colorado and Mexico. Formerly 

 confused with T. scaposa (DC.) Greene. 



Tetraneuris fastigiata Greene, of Kansas, differs by 

 the leaf-bases and involucre being more densely pubes- 

 cent ; it is known only from imperfect specimens, and 

 may not be distinct from T. stenophylla, over which it 

 has priority of publication. 



3. Tetraneuris acaulis (Pursh) Greene. 

 Stemless Tetraneuris. Fig. 4539. 



Gaillardia acaulis Pursh. Fl. Am. Sept. 743. 18 14. 

 T. acaulis Greene, Pittonia 3: 265. 1S98. 

 Actinella acaulis Nutt. Gen. 2 : 173. 1818. 

 Picradenia acaulis Britton, Mem. Torr. Club 5: 339. 



1894. 

 T. simplex A. Nelson, Bot. Gaz. 28: 127. 1899. 



Perennial with thick roots and a stout branched 

 caudex; scapes tufted, rather stout, or slender, 

 densely silky or tomentose, 2'-8' high. Leaves all 

 borne on the ends of the branches of the caudex, 

 linear-spatulate, entire, obtuse or obtusish. i's' 

 long, ii" 3" wide, densely silky or villous; heads 

 p"-l8" broad; involucre hemispheric, its bracts 

 densely villous, acutish; rays 10-15; pappus of 5 

 or 6, ovate or oblong, awned scales. 



In dry or rocky soil, North Dakota to Assiniboia, 

 Montana, Nebraska and New Mexico. May-Aug. 



Tetraneuris scaposa (DC.) Greene, admitted into 

 our first edition as from Nebraska, is not definitely 

 known north of Texas. 



4. Tetraneuris herbacea Greene. Eastern Tetra- 

 neuris. Fig. 4540. 



T. herbacea Greene, Pittonia 3: 268. 1898. 

 Actinia herbacea Robinson, Rhodora 10: 68. 1908. 



Perennial by a stout thick caudex ; scape stout, villous- 

 pubescent, especially above, 6'-8' high. Leaves linear- 

 spatulate, slightly fleshy, bluntish, strongly punctate, spar- 

 ingly loosely long-hairy, at least toward the base, 2'-3' long, 

 about 3" wide; heads nearly 2' broad; involucral bracts 

 oblong, obtuse and rounded at the apex, densely villous; 

 rays about 15; pappus scales ovate-oblong, obtuse, acute or 

 apiculate. 



Southern Ontario, Ohio and Illinois. May-June. 



83. HYMENOXYS Cass. Diet. Sci. 



Nat. 55 : 278. 1828. 



[Picradenia Hook. Fl. Bor. Am. 1: 317. 1833.] 



Pubescent herbs with branching stems and alternate entire or dissected leaves, the blades 



or divisions narrow, usually linear or filiform, and relatively small, peduncled, radiate or 



discoid yellow heads. Involucre turbinate to campanulate, its bracts in 2 series, appressed, 



