EDGAR lULLib 



651 



to set fruit. The cause lies in the untimely supply of heat and water during 

 the rest period of the plant, which needs three years for its development. 

 After the plants from the sprouts (suckers) of already fruited plants have 

 grown for two years in hot beds, they are planted in the autumn of the 

 third year in beds close under the glass of greenhouses which are built flat 

 purposely for pineapple growing. These beds are kept at a high soil tem- 

 perature by bottom heat. When the plants are well rooted at a temperature 

 which should he between 25 to 2^ degrees C. the heat must be decreased at 

 least 10 to 12 degrees C. and a marked, dry period begin. Only if the 

 plants have thus been given a complete rest, may the forcing begin again in 

 February, when the former degree of heat in the soil is allowed to act again 

 on the plants and the soil very soon well watered with warm water. If, 

 after 4 to 6 weeks, the leaves of the plants begin to spread out and to 

 become colored at the heart, it may be concluded that the fruit is setting. 

 For fear that the decrease of temperature may injure the pineapple the 

 moisture and heat are often not sufficiently reduced and the result is a 

 continued growth of the plant with the exclusive production of leaves. 



According to reports made by Cousins^ the same phenomena appear in 

 the cultivation of the pineapple in the tropics. 



The Glassiness of Orchids. 



Two cases may be briefly mentioned here in which plants of Oncidium 

 developed young shoots, nearly all of which showed a glassy, translucent 

 consistency. A few days after the appearance of the glassy places, at the 

 base of the bulbs, the shoots fell over and decayed. Since parasites could not 

 be found in the initial stages of the disease and the slendemess of the older 

 shoots indicated great heat and moisture, the plants, without any further 

 treatment, were brought into a cooler, brighter conservatory. After a few 

 weeks, the phenomenon had disappeared. 



Failure in Forcing Blossom Bulbs. 



Often, after very hot summers, gardeners complain that, contrary to all 

 expectations, the blossom bulbs develop poorly; that, when the usual tem- 

 perature was used, the blossoms pushed unsatisfactorily out of the bulbs 

 and these began to decay. Bulbs set out later than usual for forcing and 

 cultivated with less heat, however, gave perfect blossoms. 



From the dift'erent cases with which I have become familiar, I have 

 formed the following theory: if a period of warm weather occurs in the 

 early summer, when the bulb fields are in the midst of their most vigorous 

 development, the foliage is killed prematurely by heat and the bulb becomes 

 ripe prematurely. Under such circumstances, the material which later, in 

 forcing, should furnish the starch dissolving enzymes, seems to be formed 

 in insufficient amounts. If, in forcing the bulbs in winter, the usual high 



1 Revue cult, colon. 1902, No. 92. 



