185 



nary protective coats. In the spring the erything above the surface of the ground 

 seed leaves of numerous seedlings may dies, while the plant continues in the 

 be seen at the approach of night to rise form of underground bulbs, tubers, or 

 upward and come together, just as the various thickened structures. This hab- 

 palms of the hand may be placed together it of seeking a subterranean retreat at 

 over one's head. This reduces the sur- the approach of some dangerous sea- 

 face of exposure and the danger of chill son is a very good one, and is found in 

 at least one-half. Darwin experimented many of our early spring plants. This 

 upon these seedlings, and discovered that subterranean habit has a great advantage 

 by preventing some of the seed leaves over the annual habit, since a seed is very 

 from moving, the seedlings were serious- slow in bringing the plant back again, 

 ly injured. The leaves of very many while a bulb can produce its plant very 

 plants assume a peculiar night position rapidly. 



which tends to meet the danger of loss of Still other plants preserve more of 

 heat. Often the three leaflets of the com- . their structures than either the annuals 

 mon clover, if growing in an exposed O r the ground-loving plants. For exam- 

 place, may be observed to fold together pl j most of our trees have cultivated 

 into a sort of tent-like arrangement. what is known as the deciduous habit, 



Many plants are also observed to pro- that is, they merely drop their leaves, 

 tect themselves against rain, as it is nee- which are the endangered structures, at 

 essary for leaves to avoid becoming wet. the approach of the unfavorable season, 

 If the water is allowed to soak in, the an d renew them again when the favorable 

 work of the leaves is at once interfered conditions return. It should be remark- 

 with. Hence it will be noticed that most e d that these leaves do not fall because 

 leaves are able to shed water, partly by they are broken off, but that in a certain 

 their position, partly by their structure, sense it is a process of growing off, which 

 In many plants the leaves are so arranged i s carefully prepared for. One of the 

 that the water runs off toward the stem ; most prominent features associated with 

 in other plants the rain is shed outwards the deciduous habit is the autumnal col 

 as from the eaves of a house. Some of the oration. The vivid colors which appear 

 structures which prevent the rain from m the leaves of many trees just before the 

 soaking in are a smooth epidermis, lay- time of falling have attracted a great deal 

 ers of cuticle, hairy coverings, etc. In- o f attention, but although it is so promi- 

 teresting experiments may be performed nent, the causes for it are very obscure, 

 with different leaves to test their power it will be noticed that this autumnal col- 

 of shedding water. If a gentle spray be oration consists in the development of 

 allowed to play upon different plants it various shades of two typical colors, yel- 

 will be observed that the water glances i O w and red. It is known that the yellow 

 off at once from the surfaces of some j s d ue to the breaking down of the green 

 leaves, runs off more slightly from oth- substances, so that it simply indicates a 

 ers, and may be more or less retained by p Os t mortem change, as may be noticed 

 others. m connection with the blanching of cel- 



Perhaps the most general preparation ery in which the leaves and upper part of 



for protection in our region is that which the stem may be green, the green may 



is made for the coming of the winter's shade gradually into yellow, and finally 



cold. In many cases plants do not at- into the pure white of complete blanch- 



tempt to protect their delicate structures ing. The red coloring matter, however, 



from the severity of winter, but disap- is very different. Certain experiments 



pear entirely, leaving only well-protected upon plant colors have indicated that the 



seeds to carry them ove~r into the next presence of the red slightly increases the 



growing season. This results in the so- temperature by absorbing more heat. It 



called "annual habit," which has been is suggested that th<e red color may be a 



learned by many plants in order to es- slight protection to the living substance 



cape a season of danger. Other plants which is ceasing to work, and which is in 



do not disappear so completely, but ev- danger of exposure to cold. If this be 



