652 



temperature is made use of at the customary time, the stimulus of the heat 

 for these prematurely ripened bulbs is too great, since they require a slower, 

 more gradual sprouting with lower temperature. If this requirement is not 

 taken into consideration, the reserve substances are not used, as normally, 

 in nourishing the inflorescence and the bulbs decay. 



Another case in which similarly the usual forcing method fails, be- 

 cause the temperature usually found to be best proves to be too high, is seen 

 in the "falling over of tulips." In certain early varieties (pink blooming), 

 it has been observed that the peduncles break over before the blossoms open. 

 A glassy spot i to 2cm. long, appears below the node out of which leaves 

 spring in these varieties (several centimeters above the neck of the bulb). 

 The gradual shrivelling of this spot causes the breaking over of the stem. 



investigation proved an abundance of starch throughout the whole 

 bulb body along with an unusual amount of peroxydases. In forcing, it 

 was found, however, that with a high increase of temperature, the starch 

 was insufficiently dissolved, i. e., too little constructive material was sup- 

 plied to those forced aerial parts. The medullary tissue of the stalk, poor 

 in contents, was torn at this glassy place, because of the rapid elongation, 

 thus destroying the rigidity of the stalk. Bulbs, from the same shipment, 

 which were set out some weeks later, i. e., nearer their natural time of 

 developing and in the same temperature, developed normally. It is thus 

 seen how the same temperature in the conservatory can act favorably at 

 one time, unfavorably at another, according to the weather of the previous 

 year and the constitution of the bulbs, and it is advisable at the beginning 

 of the time of forcing to make some preliminary tests. 



In lilies of the valley, the same circumstance of unusually rich starch 

 production with an insufficient supply of starch dissolving enzymes mani- 

 fests itself in the scanty development of the blossom sprays. At first only 

 a few of the lowest blossoms of the sprays develop and only after these 

 have withered do the upper bells open. For this reason, forced lilies of 

 the valley often become unsalable as market plants. For such cases the 

 process used by Garden Inspector Weber^ of Spindlersfeld can be recom- 

 mended. He watered the pips with water at 44 degrees C. before planting. 

 At any rate, the dissolving of the reserve svtbstances was hastened by this. 



It is evident from these examples that the dormant plant parts must 

 have reached a definite condition of maturity for success in forcing, which 

 condition is characterized by a sufficient supply of starch dissolving enzymes. 



Seed Which Has Suffered From Self Heating. 



Without going into the much mooted question whether the self-heating 

 of unripe seed, or of seed stored in a moist condition, takes place from the 

 effects of oxydases, or from micro-organisms, as in hay', or from both 



1 "Gartenflora," Berlin, 1907, Part 2, p. 26. 



2 Miehe, H., tJber die Selbsterhitzung- des Heues. Ai-b. d. Deutsch. Landw. Ges. 

 Part 111, 1905, p. 76. 



