O. N. Purvis 343 



The rainfall during the period of investigation is shown in Fig. 1. 

 Heavy rains occurred at the beginning of the investigation, but from 

 May 25th onwards rainfall was scanty until after the last material had 

 been collected. 



The spring of 1917 was very cold, but during the period of investi- 

 gation the shade temperature was on the whole high, as may be seen 

 on an examination of Fig. 2, in which the maximum and minimum shade 

 temperatures on each day are plotted. 



The crop weight for the summer was not widely different from the 

 average for the ten years 1906-1915, but the effect of potash on the 

 yield was intensified, possibly by the dryness of the year. 



Yield -per acre, 1st crop only. 



Dactylis was not plentiful on any of the plots, and very little occurred 

 on Plot 10. Rumex indicating the acidity of the soil was plentiful on 

 the two plots (9 and 10) which had received ammonium sulphate. 



Specimens of the third internode below the inflorescence were collected 

 at intervals during the summer of 1917, on May 16th, May 31st, June 

 8th, June 15th and June 26th. On May 16th the inflorescence could be 

 felt as a swelling hidden by the younger leaves, while the stem was but 

 slightly developed and not more than from two to eight centimetres 

 long. On this occasion, the first internode below the inflorescence was 

 used, and five specimens taken from each plot. On May 31st the inflores- 

 cences were above the leaves, and the stem well developed; ten speci- 

 mens were taken from each plot. On subsequent dates only five speci- 

 mens were taken, on account of the small amount of Dactylis occurring 

 where nitrogenous manures had been applied. The hay was cut on 

 July 6th. 



The stems were fixed for twenty-four hours in acetic alcohol, and 

 washed and preserved in 70 per cent, spirit. A section of each specimen 

 was cut, stained with safranin and aniline blue, and mounted in Canada 

 balsam. Measurements were made by means of an eye-piece micrometer, 

 using a Zeiss J^ inch oil immersion objective. 



The internodes selected were enclosed by the leaf-sheath, and were 

 slightly flattened and winged (Fig. 3). An outer ring of bundles was 

 embedded in the sclerenchymatous zone, which adjoined the epidermis 



23—2 



