14 



There is much more to be said eventually about hybrid sun- 

 flowers, but some of them are very puzzling. We have a long 

 series of plants grown from H. annuus pollinated by different 

 perennial species, but showing only annuus characters. Other 

 annual X perennial crosses have given quite different results, 

 and at present we cannot pretend to understand the various re- 

 sults obtained. Experiments by Sutton in England have proved 

 no less perplexing.* 



The doubling of the rows of rays in annual sunflowers appears 

 to be an old character. La Farge, in "One Hundred Master- 

 pieces of Painting" (1912), reproduces a painting by Van Dyck 

 (1599-1641), in which appears a very large sunflower, with two 

 or three rows of rays. 



CONCERNING SOME SPECIES OF CARDUUS IN 

 COLORADO 



By Geo. E. Osterhout 



A perplexing group of plants in Colorado is made up of the 

 species of Carduus. There are quite a number of species and 

 there are many forms which are intermediate, and do not con- 

 form to the descriptions of the recognized species. Dr. Rydberg 

 accounted for many of these by recognizing them as hybrids. 

 Bull. Torrey Club 37. But it is not certain that all these forms 

 are hybrids, and if some of them originated in that way, in time 

 they may have become species, and should be so recognized. 

 Carduus OsterhotUii Rydb., Bull. Torrey Club 32: 131. 



One of the species of the high mountains accords more or less 

 with the description of Cirsium Hookerianum Nutt. The type 

 locality of this is much farther north, and Dr. Gray did not credit 

 it to the Colorado mountains. In the Synopt. Flora N. A. he 

 says: "Upper wooded and subalpine region of the Rocky Moun- 

 tains, north of lat. 48°." There is rcasonal^le doubt if this 

 northern plant is found in the Colorado mountains, but Prof. 



* Stand. Cyclop. Hort., 6: 3281. 191 7- The //. annuus X cucumcrifolius 

 hybrid was reported by A. Andree in 1913, and again (from plants grown in Sweden) 

 by Lundstrom in 1914. (Cf. Bot. Centralbl., 1915, No. 10, p. 242; 1916, No. 2, 

 p. 31.) See also Journ. of Heredity, 1915, p. 545. 



