1917] HORTICULTURE. 343 



iu growth and for the whole year more than double the growth than that made 

 by trees with the roots bare of earth. A year from transplanting nearly 34 

 per cent of the former and less than 2 per cent of the latter were producing 

 coffee. 



Fertilizer experiments with coffee were continued. As heretofore, large in- 

 creases in yield have been obtained as a result of fertilizing. In a pot experi- 

 ment nitrogen has been clearly shown to be the element which is most needed 

 for the production of a satisfactory new growth. These experiments show 

 tliat a need for nitrogen may be indicated by a yellowish-green leaf color. In 

 addition to producing a darker green and more vigorous new growth, nitrogen 

 has had the effect of increasing the number of leaves per plant. Some new 

 experiments were started to determine the value of nitrogen from different 

 sources and also the effect of lime on coffee planted in red clay soil. A fur- 

 ther planting of seedlings from a coffee tree which bore both variegated foliage 

 and green leaves indicates that the variegation can be transmitted, although 

 the green foliage is dominant in the offspring. 



In tlie work with cacao the individual yields of more than 300 trees are 

 being recorded. Records have now been kept a sufficient time to show the 

 prolific tendencies of certain individuals. The maximum yield recorded from 

 a single tree at a single picking has been 54 pods. Pickings are made every 

 four to six weeks. For the calendar year 1914 about one-fourth of the trees 

 which were set 11 years before produced no crop. The others averaged 17.5 

 pods, or a gross return of about 22 cts. per tree. One hundred seedlings from 

 one of the most vigorous and prolific trees have been planted in order to study 

 the differences to be found in seedlings derived from the same tree. Studies 

 lire also being made to determine whether there is any correlation between 

 light and dark cotyledons and light and dark beans, the color of the bean being 

 commonly supposed to indicate the quality of the bean. 



In the work with vanilla attempts to raise hybrid vanillas from seed have 

 been unsuccessful thus far. Experiments with different lengths of vanilla 

 cuttings for propagating have shown unquestionably that with cuttings up to 

 those of 12 internodes every advantage lies with the longest cuttings. In view 

 of a common opinion that vanilla is a lime lover, applications of lime were 

 applied to four vanilla beds at the rate of 1, 2, 4, and 8 tons per acre. The 

 results indicate that whereas a light liming may be somewhat beneficial heavy 

 liming tends to retard growth. 



Freezing-point lowering of the leaf sap of the horticultural types of 

 Persea americana, J. A. Harris and W. Popenoe (U. S. Dept. Agr., Jour. Agr. 

 Research, 7 {1916), No. 6, pp. 261-268). — The results are given of a study of the 

 freezing-point lowering in the cell sap of the Mexican, Guatemalan, and West 

 Indian types of avocados, the plant material being secured from trees growing 

 at the Miami Plant Introduction Field Station. 



All of the types showed considerable variation in freezing-point lowering. 

 The range in the freezing point of the sap for the whole series was from 29.43 

 to 30.27° F. Within the type the absolute variation in freezing-point lowering 

 is very slight, amounting to 0.1° C. or less. The average freezing-point lower- 

 ing in the Guatemalan and Mexican types was practically the same. The 

 West Indian type is characterized by^ tissue fluids which freeze at a distinctly 

 higher temperature than in the two other groups of varieties, and is the one 

 which has been shown by horticultural experience to be the least capable of 

 .enduring cold. The authors conclude, however, that capacity to withstand 

 low temperatures is not solely due to differences in the freezing point of the 

 sap, this being evident from the slightness of the differences in the cryoscopic 



