June 23, 1899.] 



SCIENCE. 



881 



3. Zea indurata, the flint corns, in wliicli the 

 corneous endosperm encloses a mass of starchy 

 endosperm, the summit of the Iternel being in 

 all cases covered by the corneous layer. Sixty- 

 nine varieties are recognized, among which the 

 common ' Eight-rowed corn of New England ' 

 is a familiar example. 



4. Zea indentata, the dent corns, in which 

 the corneous endosperm occurs at the sides only 

 of the kernel, the starchy endosperm extend- 

 ing to the summit. By the drying and shrink- 

 age of the starchy matter the summit of the 

 kernel becomes indented, whence the name 

 ' dent ' corn. No less than 323 varieties are 

 recognized as belonging to this ' species group,' 

 of which the common corn of the Central 

 States, North and South, furnishes many ex- 

 amples. 



5. Zea amylacea, the soft corns, characterized 

 by the absence of corneous endosperm. Twenty- 

 seven varieties are recognized. Tuscarora, 

 Cuzco and Zuni are examples. " The mummy 

 corns, from Peru and Chili, that I have 

 examined have been soft corns in four varieties. ' ' 



6. Zea Zaccarata, the sweet corns, character- 

 ized by the translucent, horuy appearance of 

 the kernels, and their more or less crinkled, 

 wrinkled or shriveled condition. Sixty-three 

 varieties are recognized. 



While we may not be willing to accept these 

 ' species groups ' as species in the ordinary 

 sense, it is fair to say that, in our opinion, they 

 are as much entitled to specific rank as many 

 of those which have been described recently. 

 If the systematic botanists ever turn to such 

 plants as Maize, Wheat, etc., we may expect 

 not only the acceptance of the forms indicated 

 above as good species, but also the addition of 

 many more. 



THE AGB,ICnLTURji.L GRASSES OF KANSAS. 



A RECENT Experiment Station Bulletin (No. 

 87) issued by the Kansas Station contains some 

 matter of more than visual interest to botanists. 

 It deals with the grasses of importance to agri- 

 culture, and on that account might be supposed 

 to contain little, if anything, of value to the 

 scientific botanist, but it requires only an ex- 

 amination of this bulletin to show that one can- 

 not judge of the value of a paper by the title. 



Professor Hitchcock has made a paper of much 

 interest to the botanist, and we dare say that it 

 is not one whit less useful to the farmers for 

 whom, primarily, it was written. Twenty-six 

 species of wild grasses are mentioned, and, by 

 means of illustrations and popular descriptions, 

 their identity will not be difficult for the farmer 

 and stockman. To the botanist the neat little 

 maps which show the distribution of the species 

 are full of interest, as are also the paragraphs 

 which indicate, popularly, it is true, the main 

 phytogeographic features of the State. The 

 latter areas follows : Wooded regions ; sloughs, 

 swales and wet meadows ; bottom lands ; 

 prairies of eastern Kansas ; sandy regions ; 

 stony hills ; salt plains and alkali spots. One 

 cannot but regret that the text is disfigured by 

 the spelling 'thru ' and 'thruout,' but we sur- 

 mise that this is not to be laid at the door of 

 the writer of the Bulletin. 



DISEASES OF THE SWEET POTATO. 



That delicious vegetable, the sweet potato, 

 is affected most grievously by diseases which 

 must make life a burden to the grower, what- 

 ever they may do to the unfortunate plants 

 themselves. In a recent bulletin issued by the 

 Maryland Experiment Station, Dr. C. O. Town- 

 send described eight diseases of the sweet po- 

 tato. These are known under the following 

 names : Black Rot, Soil Rot, Soft Rot, Stem 

 Rot, White Rot, Dry Rot, Scurf, Leaf Mould. 

 In every case the disease is produced by a fun- 

 gous parasite which attacks the tissues. Thus 

 Black Rot is caused by Ceratocystis fimbriata; 

 Soil Rot by Acrocystis batatas ; Soft Rot by the 

 ubiquitous 'black mould' Bhizopus nigricans; 

 Stem Rot by Nectria ipomoeie ; White Rot by 

 some Penicillium ; Dry Rot by Phoma batatss; 

 Scurf by Monilochieies infuscans; Leaf Mould 

 by Albugo (Cystopus) ipomcese-panduranie. Nine 

 years ago Dr. Halsted, of the New Jersey Ex- 

 periment Station, published a similar paper 

 (Bulletin 76) in which he described still another 

 disease of this sorely afflicted plant, viz., Leaf 

 Blight caused by Phyllosticta hataticola, making 

 nine diseases in all. The remedies to be em- 

 ployed by the growers include the following : 

 Discard all diseased sets ; spray with Bordeaux 

 mixture ; rotate crops ; treat the soil with sul- 



