692 EXPERIMENT STATION RECORD. 



genera and species known to occur within the State are given, and 

 under the specific descriptions are added economic notes whenever they 

 would be of value or interest. In the descriptions of the tribes and 

 genera notes are given on their numerical abundance and geographical 

 distribution throughout the world, from which their relative represen- 

 tation in tbe region covered by the bulletin may readily be seen, Tliere 

 are more than 200 species and varieties of introduced and indigenous 

 grasses described, representing (35 gewera of 11 tribes, and most of them 

 are figured, some for the first time. The illustrations, which were 

 especially prepared for this work, show the general habit of the plant, 

 the inriorescence and dissections of the si)ikelets, the latter being- 

 drawn to a larger scale than those showing the entire plant. For nearly 

 every genus of more than a single species an analytical key of species is 

 given that will materially aid in the determination of specimens. A 

 feature of the bulletin is the index and glossary in which every scientific 

 name and technical term used is concisely defined, in addition to the 

 usual references to figures and pages. The most widely known common 

 name of each species is given, and the scientific nomenclature is not 

 burdened with a list of synonyms that are valuable only to a specialist. 

 The nomenclature followed is in the main that used in the manuals cov- 

 ering the same region. The bulletin, while containing only the grasses 

 of Tennessee, will be valuable to most of the eastern and central part of 

 the United States, the region covered by Gray's Manual, the edition of 

 1890 of that work containing less than a score of genera not included 

 in this bulletin. 



Notes on maize, E. L. Sturtbvant {Torrey Bui., 21 {1894), No, 12, 

 pp. 503-523). 



Synopsis. — Notes are given on crossinjj of species, crossing of varieties, mummy 

 corn, effect of climate on tlie growtb, growing season required for corn, and 

 the i^hysiology of pop corn. 



The author thinks from the data given that it is highly probable 

 that cross-fertilization is very common, at least within each species, but 

 that there is some resistance to hybridization; however, more data 

 are required before claiming the demonstration of the generalization. 

 Within varieties color variation is very common. Descriptions are given 

 of 4 varieties of mummy corn, 3 of which are from Peru, the other from 

 Chile. All belong to the species Zea amylacea. The author offers a 

 few generalizations on the effect of climate on corn. He says the com- 

 mon belief that a northern climate increases earliness and decreases 

 size is not borne out by his observations, and the idea that we must go 

 Korth for seed is untenable except that in the North are found only 

 varieties maturing within certain periods. He thinks earlier corn must 

 be sought by finding earlier varieties, whether in the iSTorth or South. 

 The author gives as an explanation of the phenomenon of corn pop- 

 ping the fact that hot water causes starch to become plastic. In the 

 pop coru the starch lies Avithin a very tough endosperm and the applica- 



