444 



EXPERIMENT STATION RECORD. 



In the group Spheriacese. It is considered doubtful whether truffles, puffballs, etc., 

 ran form tnycorrhiza. 



The decomposition of dead leaves in the forest, E. Henry ( .1////. Sci. Agron., 

 ..'. ser., 1902-3, II, No. 3, pp. 328-333). — The author found that in the case of leaves 

 placed in zinc boxes, or brought in contact with zinc salts, the action of the bacteria 

 causing decomposition of the leaves was greatly checked. When compared with the 

 same leaves under normal conditions the decomposition was reduced about half 

 during the first year. In some cases only about 15 per cent decomposition took 

 place within a year. Leaves of some species were found to decompose much more 

 rapidly than others, and the leaves of the hornbeam, although much less coreaceous 

 and containing much less tannin than oak leaves, are not decomposed as rapidly as 

 the oak leaves when submitted to normal conditions. 



Fixation of the atmospheric nitrogen by dead leaves in forests, E. Henry 

 {Ann. Sci. Agron., 2. ser., 1902-3, II, Nos. 2, pp. 313-320; 3, pp. 321-327).— -The 

 results of some recent experiments on the fixation of nitrogen by leaves are given, 

 and the author concludes that dead leaves of the oak, beech, hornbeam, poplar, 

 Austrian pine, and spruce are able, either alone or mixed with soil, when in a moist 

 substratum, to fix considerable portions of nitrogen from the air. Leaves of pine, 

 beech, and spruce placed in pure sand or in a poor dry soil were either unable to take 

 up any atmospheric nitrogen to enrich the soil, as in the case of the beech, or to 

 assimilate a very slight amount, as in the case of the leaves of pine and spruce. In 

 none of his experiments was there any loss of nitrogen. 



The enzym-seereting cells in seedlings of maize and dates, H. 8. Reed 

 {Ann. Bot., IS (1904), No. 70, pp. 267-287, pi. 1). — In continuation of the preliminary 

 account previously noted (E. S. R., 15, p. 752), the author has studied the enzym- 

 secreting cells of seedlings of Zea mais and Phoenix dactylifera. It was found that in 

 the resting condition the secreting cells of both maize and dates are crowded with 

 relatively small proteid granules. As secretion begins these granules gradually dis- 

 appear. In maize the disappearance coincides closely with the consumption of the 

 endosperm. In the date, however, the granules disappear long before the endosperm 

 is dissolved. 



The chromatin of the nuclei is small in amount at the beginning of secretion and 

 increases as germination progresses. The nucleolus diminishes with the progression 

 of germination. These changes are more noticeable in the case of maize than in the 

 date. There is no evidence that solid matter is extruded from the nucleus. At the 

 end of secretory activity the protoplasm of the secreting cells breaks down and the 

 products of disintegration disappear from sight. 



Studies on evaporation by purslane, E. B. Watson ( Wallaces' Farmer, 29 (1904), 

 No. 42, p. 1269). — The results of experiments carried on at the Iowa Agricultural 

 College, in which the effect of the growth of purslane on the temperature and mois- 

 ture of the soil is shown. The weed grew in great abundance and practically covered 

 small plats in the nursery and these were studied, comparisons being made with 

 adjacent plats which were under cultivation. The effect of the purslane on the 

 temperature of the soil is shown by the following table: 



Table showing effect of purslane on soil temperature. 



