224 EXPERIMENT STATION RECORD. 



Germination experiments with beet seed, A. \'ivikx (Xtschr. Ver. liiihem. Jud., 

 1S94, Aiuj., pp. i;.',.3-i_:-',i;). 



Reports of Oerebro Seed Control Station for 1891 and for 1892, J. AVidkn 

 (Oerehro, Sivtdeii: LS!)..', pp. 0.; IS93, pp. in). 



A contribution to the physiology of Cuscuta, 1). T. McDougal (Bot. Gaz., 19 

 (1894), Xo. 8, 2)p. 331, 332). — Notes are given of some observations on tlie haustoria 

 and the twining liabits of this plant. 



Prickly lettuce and other ■weeds in lo'wra, L. H. Pammel {Garden and Forent, 7 

 (1894), J). 35S). — A report is given on the spread of prickly lettuce (Lactuca scariola), 

 oxeye daisy (Chri/8anthemum /eMcatt^/ieHi«m), squirrel-tail grass (Hordeum juhalum), 

 spiny nightshade {Solanum rostratiim), and Mexican poppy (Argemone mericana). 



DISEASES OF PLANTS. 



Second report on rusts of grain, A. S. Hitchcock and M. A. 



Carleton {Ka7is(i.s Sta. Bui. 40^ pp. 9). 



Synojysis. — Reports are given on the additional observations of the wintering of 

 Piiccinid ruhi<io-rer(i, observations on /'. f/ramini-s, inoculation experiments, and 

 spraying experiments. 



This report. is a continuation of the jirevious report given in Bulletin 

 38 of the station (E. S. li., 5, j). 407), in which was given the life his 

 tory of grain rusts and records of experiments on the prevention of 

 rusts by means of spraying. In the previous report the opinion was 

 expressed that the spores of Puccinia riihigo-rera were not formed 

 during the winter, but probably retained their vitality from the time 

 of formation in the previous autumn, and it was left unsettled as to 

 whether the mycelium lived over winter or not. 



In order to test this point a few plants supposed to be infected were 

 transferred to the greenhouse on March 9, On March 16 a number 

 of bright red spots appeared, showing the uredospores of the rust. 

 On March !i2 observations in the field showed the rust was spreading 

 ujjon the leaves quite rai)idly. 



Culture experiments were made with the uredospores taken from 

 plants, which showed that the spores retained their vitality throughout 

 the winter. From these experiments and observations the authors 

 conclude that P. riibif/o-vera passes the winter in the tissues of the 

 wheat in a. mycelial condition, and tliat the uredospores retain their 

 vitality throughout the winter. 



The observations upon J*, graminis showed that while the rust was 

 quite abundant in 1893 it was impossible to fiml any evidence of its 

 presence during the winter, and it is probable that it does not pass the 

 winter in the vicinity of'the station either in the mycelial or uredo 

 stage. 



The authors made numerous inoculati(m experiments to ascertain 

 the relation of rusts of wheat to those of other cereals and grasses. 

 Wheat, oats, rye, barley, and corn were inocuiated with the spores of 

 P. graminis from wheat and oats, P. sorghi from corn, and P. ruhigo- 

 vera from wheat and blue grass; but in all cases no infection followed 



