1918.1 FIELD CROPS. 833 



The identification of varieties of barley, H. V. Haklan (U. S. Dept. Ayr. 

 Bui. 622 (1918), pp. 32, pis. Jf). — This bulletin presents a scheme of classifica- 

 tion of cultivated barleys, designed primarily for the use of experiment-station 

 workers and advanced students in agronomy, and aims especially to coordinate 

 previous schemes of classification, to render available work already published 

 on barley, to suggest modifications for obtaining a more logical arrangement of 

 the varieties, to add four new varieties discovered during the progress of tlie 

 work, and to serve as a basis for a discussion of all the agricultural varieties 

 of barley grown upon the farms in America. 



In describing species and varieties, only the major characters were used, 

 embracing six variable factors, namely, fertility, adherence or nonadherence of 

 the fiowering glume, outer glumes, terminal appendages of the lemma, color, 

 and density. Less important characters were utilized in describing subvarieties. 

 Keys are presented for the identification of the four recognized species of barley, 

 viz: Hordeum vulgare, H. intermedium, H. distichon, and H. deflclcns; of 32 

 varieties occurring under the four species ; and of the subvarieties. 



An alphabetical list of rejected species, subspecies, and varieties, also of 

 synonyms which have been published from time to time, has been prepared be- 

 cause " in the analysis of the relative value of the variable characters of barley, 

 a number of variations were regarded as of too minor a nature to be used even 

 in the description of named subvarieties. These included the elevation of the 

 hood on a short awn, awns produced on the hood itself, malformed awns, 

 short awns, the nature of the hairs on the rachilla, the toothing of the nerves 

 of the lemma, and the widening of only the two outermost glumes at a node. 

 Varieties established upon these characters are not recog;,nized in the key." A 

 few groups founded on characters other than those just named have been in- 

 cluded in the list. " The most important of these is probably that of compound 

 spikes. The inclusion of compound spikes as a recognized character would sim- 

 ply double the number of varieties. In barley, proliferation of spikes is com- 

 mon, but in most strains it is not inherited. In others, while the tendency is 

 transmitted, it is inherited imperfectly." 



Distinction between colors and variations of density are not deemed suffi- 

 ciently well established to be entirely satisfactory for use in taxonomic work, 

 and are regarded as fields for further study. 



The identification of thrashed barley by means of the keys is described, and 

 in the common agronomic varieties tlie chance of error is said to be negligible. 



A key has also been prepared listing a few well-known agronomic varieties 

 of barley in each of the more common subvarieties, although no attempt is made 

 to distinguish between the agTonomic varieties within a subvariety. " In the 

 varieties at present grown in America, separations are most difficult in the lax 

 forms of the common 6-rowed barleys. In general, there are two groups, the 

 Manchuria-Oderbrucker and the Coast. These groups are separated by the 

 longer, heavier grain and the more tenacious awn of the latter. Within a 

 group such as the Manchuria, identifications must be based on combinations of 

 minor characters, such as the density of the spike, the nature of the hairs on the 

 rachilla, the length of grain, and, if necessary, distinctive culm characters and 

 the length of the growing season." 



A list of 41 titles is appended, comprising the literature cited. 



The agricultural situation for 1918. — VIII, Corn. — A large acreage of 

 corn needed {U. S. Dept. Agr., Office Sec. Circ. 91 (1918), pp. i6).— This presents 

 a general discussion of the relative importance of the corn crop and of means 

 for increasing the acreage and yield per acre. The employment of improved 

 implements in preparing the land and in planting, cultivating, and harvesting 

 the crop is recommended in addition to the use of good seed, improved cropping 



