ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

 prepared and signed by themselves, are forwarded promptly to the editors. 

 The abstracts should conform in length and general style to those appearing in 

 this issue. 



BOTANY. — Germination of barley pollen. Stephen Anthony and 

 Harry V. Harlan. Journ. Agric. Res. 18: 525-536. 1920. 



The paper reports the first artificial germination of barley pollen 

 and gives in detail the methods by which this was accomplished. It 

 was found that barley pollen was extremely sensitive to moisture, so 

 sensitive that it could be killed by blowing one's breath upon it. It 

 was equally sensitive to dryness, shrinking perceptibly in two min- 

 utes when exposed to free air. A few minutes of such exposure resulted 

 in death. All attempts to germinate the pollen in solutions or upon 

 media or membranes, resulted in failure. Germination was finally 

 accomplished by exposing the pollen to an atmosphere in which the 

 humidity gradually increased. Growth of lengthy tubes occiured in 

 five minutes. H. V. H. 



BOTANY. — The genera of grasses in the United States with special 

 reference to the economic species. A. S. Hitchcock. U. S. Dept. 

 Agric. Bull. 772. Pp. 307, pis. 20, figs. 174. 1920. 



This paper contains an introduction on the scope and plan of the 

 work, including an economic classification of grasses based on uses; 

 a description of the grass family; descriptions of the subfamilies with 

 keys to the tribes, and under each tribe, keys to the genera and descrip- 

 tions of the genera. The arrangement of the tribes differs from the 

 usual presentation in that the more primitive are placed first, thus: 

 Bamboseae, Festuceae, Hordeae, Aveneae, Agrostideae, Nazieae, 

 Chlorideae, Phalarideae, Oryzeae, Zizanieae, Melinideae, Paniceae, 

 Andropogoneae, Tripsaceae. Under each genus is given a technical 

 description, with synonymy. The type of each genus is selected whether 

 the names are valid or cited in synonymy, and the reasons for the selec- 

 tion are given in all cases. Following this under each genus is given 

 information on all species that are likely to have attracted the atten- 

 tion of agriculturists. Each genus is illustrated by one figure and the 

 larger genera by more than one. There are 144 genera described. 



A. S. H. 

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