POLLEN : ITS DEVELOPMENT AND USE. 



337 



lie pretends to know all about what one is showing him. His 

 interest can be aroused only by objects the use of which is plain 

 to him without explanation, or which he fancies have a market 

 value. At them his eyes will shine with greed. Lack of self-con- 

 fidence makes him suspicious, and his distrust appears in his look. 

 His eyes will shine with his own rage, but no flame of noble indig- 

 nation can be kindled in them on account of an evil deed or of a 

 wrong of which he is the author. Translated for TJie Popular Sci- 

 ence Monthly from Das Ausland. 



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POLLEN: ITS DEVELOPMENT AND USE. 



By JOSEPH F. JAMES, M. Sc. 



WHEN a plant in growing has reached a certain stage in its 

 development, the character of the buds which have before 

 produced branches changes, and flower buds appear. In corre- 

 spondence with the change of character in the buds, the stem and 

 leaves change also. The former becomes smaller and forms the 

 peduncle of the flower, while the latter, dwindling from true 

 leaves or foliage organs, become bracts, sepals, and petals. 



The process of flowering is attended with very important re- 

 sults. While the plant has been growing rapidly, sending out 

 new leaves and branches into the air and new roots into the 

 earth, the total amount of material produced by general growth 

 has not been expended. A certain portion is kept in reserve, and 

 this is drawn upon when the time for flowering and fruiting has 

 come. It is the exhaustion of this reserve of food which causes an- 

 nuals to perish after perfecting their seed. In biennials a store of 

 matter is laid up one year in the leaves or roots, to be drawn upon 

 by the plant when the flowering time comes round the next year. 



Lamarck, about seventy years ago, was the first to detect that 

 a certain amount of heat was evolved on the expansion of the 

 flowers of the European Arum. Their anthesis is equivalent to a 

 burning up of some of the material of the plant. The heat so 

 produced is sometimes quite considerable, and it can be measured 

 by means of a thermo-electrical pile. A most notable example of 

 the consumption of stored material is to be observed in the cent- 

 ury plant. This grows for many years, laying up nourishment 

 in its large, succulent leaves. After from fifteen to seventy years' 

 growth the time for flowering comes ; the reservoir of nourish- 

 ment is drawn upon, the flower stalk is shot up with tremendous 

 rapidity, and in a few weeks the thousand blossoms have opened, 

 faded, and seeded. Then the whole plant dies. It has exhausted 

 its store of nourishment, and consumed itself in the production of 



vol. xxxix. 24 



