164 IOWA ACADEMY OF SCIENCES. 



vicinity of Ames, lowa.^" More 1han this, repeated effoits to 

 artificially inoculate various varieties of cultivated apples with 

 Gymnosporangium macropus have failed. In the spring of 

 1886 Dr. Halsted- inoculated G. macropus on two varieties of 

 cultivated apple (Rawles' Janet and Tallman Sweet), wild crab 

 Pirus coronaria^, pear, mountain ash, Pirus semipinnata, 

 several species of hawthorn and two forms of Juneberry on the 

 grounds of the Iowa Agricultural College, Ames, Iowa. In no 

 case did Roestelia appear on the cultivated apples. He says*: 

 " Tne individual experiments numbered among the hundreds, 

 and in every case there was a perfect failure of the Gymnos- 

 porangium to grow except with the crab apple, where the 

 inoculation was most emphatic." further inoculations were 

 made the following season, 1887. He says'^: "During the 

 present season cultural experiments with the native cedar have 

 been carried out by special students. It is an easy matter to 

 inoculate the wild crab with this, but only failures have 

 attended tests upon other plants." In 1893 Prof. L. H. Pam- 

 meF made some inoculation experiments at Ames. A tree of 

 the variety Tetofsky had been top worked with Fluke crab, 

 which is an 'improved variety of Pirus coronaria; G. macropus 

 was inoculated upon both parts of the tree on the same day, 

 with the same cedar apple. In due course of time, Roestelia 

 appeared in abundance upon the Fluke crab portion of the tree 

 but not a single leaf of the Tetofsky portion was affected. 

 Inoculations were also made upon pear, Japan quince {Ci/donia 

 Japonica), cultivated apple and shadbush {Amelanchier alni- 

 folia), but these all proved failures. 



The above is, in brief, the history of the experiments at 

 Ames previous to 1894. It appears to be well established, that 

 at Ames, Iowa, the cultivated apple is wholly exempt from the 

 Rcestelia disease which is very abundant and destructive in 

 New England and in some of the southern states. The Red 

 cedar does not grow spontaneously in central Iowa, but it is 



la Professor Pammel writes that be has never known or heard of Roestelia on any- 

 cultivated variety of apple in Iowa. 



2Bulletin of the Iowa Agricultural College, from the Botanical department, 

 November, 1886, pp. 59-64. 



3Bailey considers the wild Pirus of Iowa to be specifically distinct from P. coronaria 

 He has named it Pirus lowensis. See L. H. Bailey's Notesfrom a Garden Herbarium VI; 

 The Soulard crab and its rise. The American Garden, Vol. XII, p. 469. 



* I. c, p. 63. 



SBull. from the Bot. Dept. of the Iowa Agricultural College, February, 1888, p. 91. 



^Diseases of foliage and fruit. Eeport of Iowa State Hort. Soc, Vol. XXVIII, 1893, 

 p. 470. 



