256 



SCIENCE 



[N. S. Vol. XXXII. No. 816 



lie health, and the inefficiency of measures which 

 are less than national in their scope, 



"Resolved, that the Iowa Academy of Science 

 hereby expresses its hearty approval of the bill 

 ( S 6049 ) now under the consideration of the 

 national congress, for the establishment of a 

 national department of health, presided over by a 

 secretary who shall be a member of the president's 

 cabinet." 



" By virtue of the fact that there is now a gen- 

 eral movement for the conservation of our natural 

 resources, both by the national authorities and 

 more recently by the state, therefore be it 



" Resolved, that the Iowa Academy of Science in 

 session hereby reaffirms its endorsement of the 

 general movement toward the conservation of our 

 forests, rivers, lakes and mineral resources by the 

 national government." 



The next annual meeting of the academy will be 

 held at Coe College, Cedar Rapids. 



L. D. Ross, 

 Secretary 



Des Moines, Ia. 



the botanical societt of washington 



The May meeting of the society was held at 

 the Ebbitt House, May 28, 1910, at eight o'clock 

 P.M.; President Wm. A. Taylor presided. 



Dr. David Griffiths illustrated a method for 

 making permanent records of the characters of 

 the genus Opwitia. Large photographs (one half 

 natural size) are taken and from the plates two 

 prints are made, one on velox and a second on 

 platinum paper. The latter is made very faint 

 and is used as an outline by the field artist who 

 reproduces the colors of the plant from living 

 material. 



The following papers were read: 

 Professor Charles Fay Wlieeler: W. F. Wight. 



Published elsewhere in Science. 

 Starch Content of Leaves Dropped in Autumn: 



L. L. Haeteb. 



Contraiy to the accepted view that practically 

 all food materials in leaves undergo translocation 

 in autumn, the author found that dropped leaves 

 of Liquidamhar, Ginkgo, Styra-x and some oaks 

 contained starch in amounts varying from 6 to 14 

 per cent. 



Pacts Contributing to the Explanation of Grain 



Rust Epidemics: Edw. C. Johnson. 



In this paper it was shown that wintering 



uredos, wind-blown uredospores or tecidiospores 



are usually present in sufficient quantities to start 



rusts every year. That uredospore germination 

 and infection in many rusts takes place most I 

 easily at the relatively low temperatures of ' 

 to 70° F. was demonstrated. It was further shown I 

 that wheat is particularly susceptible to infectionJ 

 of Puccinia graminis at heading time. If this] 

 period is delayed by a late season, or is undulyl 

 lengthened by reason of low temperatures the] 

 number of spores falling on each plant is propor- 

 tionately increased, and the rust given unusual ] 

 chances to develop. Subnormal temperatures — 1 

 especially cool nights with heavy dews — are ex- 

 ceedingly favorable to rust infection at this time, | 

 far more so than excessive rainfall due to sudden J 

 showers with periods of high temperatures be- 

 tween. 



An analysis was made of climatological condi- 

 tions over the middle northwest during 1903, 1 

 1904 and 1905, and it was demonstrated that 

 although precipitation and relative humidity were 

 greatest in 1905, both during the growing and 

 heading period, stem rust was most severe in 1904 

 when temperatures averaged 3.5° F. subnormal 

 over this region, this being considerably lower 

 than temperatures in either 1903 or 1905. 



On the Transmission of Characters without Ex- 

 pression in Vegetables: W. W. Tbact, Sb. 

 Red Narragansett, probably an aboriginal va- 

 riety of sweet com, was bred in one direction into 

 Red Cory by crossing with an eight-rowed flint 

 squaw corn of New England. From this was 

 selected a White Cory which bred true with no 

 trace of red for many years. From Red Narragan- 

 sett was also obtained by selection Early Marble- 

 head, and this it is surmised was carried to 

 Russia by a missionary. Later Early Malakoflf 

 was imported from this part of Russia. This com 

 showed no traces of Red Narragansett. In an 

 accidental cross of White Cory and this Alalakoff 

 corn there appeared thirteen plants which pro- 

 duced a com like Red Narragansett, showing that 

 the characters of the parent variety were carried 

 hidden for many years, to appear again when the 

 two strains were crossed. 



A similar case of unexpressed transmission was 

 noted in a variety of cabbage, the Early Winnig- 

 stadt, strains of which were established by selec- 

 tion in 1885. One of these strains showed a small 

 percentage of Green Glaze cabbage which has 

 been carried for twenty-five years, although no 

 plant of Green Glaze has ever been allowed to 

 furnish seed in this strain. 



W. W. Stockbebgeb, 

 Corresponding Secretary 



