BOTANY. 745 



It also caused the fonnatiou of a riug of woody tissue both in the stem 

 and the root, while with the plants in the distilled water the vessels 

 were ajj^iiregated in isolated groups, their number and arrangement 

 varying considerably. The Knop solution also thickened the internal 

 portion of the pericycle of the root. It diminished the lignification of 

 the endodermis of the root and admitted of a very considerable devel- 

 opment of these cells. It also increased the dimensions of the cells of 

 the bark and i)itli. 



The conclusions reached from the experiments with rye are analogous 

 to those given for the lupine. 



In the second part of his work the author studied the special action 

 of each salt, comparing it as before. In this case the plants were 

 grown in series in the Knop solution, one salt being omitted in each 

 series. 



It was seen that tlie morphological characters of the lupine were 

 greatly modified by the different salts. Sulphate of magnesia tends to 

 retard the development of the plant, although it seems to be indispen- 

 sable. The nitrates of lime and potash are esiiecially valuable to the 

 plant during its earlier periods of growth, but later they become some- 

 what inefficient, especially the nitrate of potash. The phosphate of 

 potash is absolutely indispensable, and it induces a greater development 

 of roots. Its absence is shown by the atrophy of the roots and elonga- 

 tion of the hypocotyl. 



In the experiments with rye it was seen that the growth of the aerial 

 parts of the plants was most active in the solution which did not con- 

 tain sulphate of magnesia. There was considerable elongation of roots 

 in the absence of nitrates, as observed with the lupines. The phosphate 

 of potash was shown to be indispensable to the growth of both stem and 

 root. 



Plat experiments were carried out in which the same solutions were 

 tested by applying them when watering the plants. The results obtained 

 are indicated by curves showing the development of the different j^arts 

 of the plants for each solution. The experiments conducted in the open 

 air confirm the conclusions already given for the water cultures. 



The influence of fruit bearing on the development of mechan- 

 ical tissue in some fruit trees, A. J. Pieters {Ann. Bot., 10 {1896), 

 Xo. 40,2)P' 511-520). — The author gives a resume of literature relating 

 to this subject, all the citations being dated since 1878. In his inves- 

 tigations studies were made of shoots of apple, pear, peach, and plum, 

 comparing vegetative and fiuit- bearing shoots from the same branch 

 or tree, and as nearly as possible comparable. Free-hand sections were 

 made and the tissues measured with an ej^e micrometer. Two measure- 

 ments were taken at right angles to each other and the average thick- 

 ness of the zones of tissues determined. 



The material was studied in reference to the following questions: 



"(1) Is the xylem cylinder in a l-year-old fruit-bearing shoot less well developed 

 than in a vegetative shoot of the same age and apparent vigor, and does it form a 

 smaller proportion of the diameter of the shoot f 



