28 BULLETIN" 622, U. S. DEPARTMENT OF AGRICULTURE. 



medium this extension is characteristic of the lateral florets of lax 

 varieties as well. In barleys with awnless lateral kernels the obser- 

 vation should be made upon the central kernel. In the naked varie- 

 ties density can not be determined with certainty from thrashed 

 specimens. 



VARIETIES GROWN IN FIELD CULTURE IN THE UNITED STATES. 



Students and experimenters usually are interested in the variation 

 that occurs in a crop as a whole, but there are also times when they 

 are concerned only with local forms. For this reason it has been 

 thought advisable to include a short list of the varieties and sub- 

 varieties which are grown in field culture in the United States. 

 Although a very small percentage of the total number of forms is to 

 be found, they are distributed through the groups in such a way as 

 to be quite representative. The only forms which are entirely lack- 

 ing are the deficient, wide-glumed, and smooth-awned varieties and 

 subvarieties. The wide-glumed forms are not found in pure culture 

 even at our experiment stations. Deficient barleys are grown at but 

 few stations, and smooth-awned varieties at even a less number. The 

 writer has a considerable number of smooth-awned selections in field 

 tests in cooperation with the Minnesota Agricultural Experiment 

 Station and elsewhere. Hordeum vulgare pallidum and TI. distichon 

 palmella include most of the agronomic varieties grown. The greater 

 proportion of varieties in each case is found in the lax subdivisions. 

 The following key includes a few well-known agronomic varieties 

 in each of the more common subvarieties. 



KEY TO COMMERCIAL VARIETIES. 



Spikelets all fertile (6-rowed barleys). 



Lateral florets awned or hooded (sp. vulgare). 

 Kernels hulled. 



Lemmas awned. 



Kernels white, blue, or purple (var. pallidum). 

 Kernels white. 



Spike narrow, las, nodding subvar. typica. 



Represented by the agricultural varieties Man- 

 churia, Oderbrucker, Tennessee Winter, and 

 white strains of Coast (Bay Brewing), etc. 

 Spike wide, very dense, pyramidal, awns widely 



spreading subvar. pyramidatum. 



Represented by the agricultural varieties Win- 

 ter Club (White Winter or Utah Winter), 

 Tapps Winter, and Mariout. 



Kernels blue subvar. coerulescens. 



Represented by blue-gray strains of Coast and 

 several pedigreed selections of Manchuria. 



Kernels black var. nigrum. 



Represented by the agricultural variety Gatami. 



