THE AMERICAN BOTANIST 



69 



plantago-aqiiatica) on the Pacific Electric right of way, about 

 half way between Los Angeles and Long Beach. I am told this 

 is the first record for this plant in Southern California. I also 

 found a plant of Lcpidktin pcrfoUatuiii on a hillside north of 

 Los Angeles. Dr. A. Davidson found a few plants in Holly- 

 wood in 1910, but it is not common. — George L. Moxley. 



RuDBECKiAS AND MoiSTURE. — Miss Nell McMurray ob- 

 serves that black-eyed Susans (Riidbeekia hirta) belie their 

 sturdy looks in one sense : one must hurry home after gather- 

 ing them because they soon wilt and once wilted water will not 

 revive them. This peculiarity is not confined to Rudbeckias, 

 however. A large number of plants that seem able to^ with- 

 stand almost any amount of dryness when rooted in the soil, 

 quickly wilt when severed from their roots. We expect such 

 behavior in water plants since they are generally so adjusted 

 to a watery habitat that they possess no means of retaining the 

 water in their tissues and, indeed, do not need such adaptations 

 in their habitats. But in the plants of dry regions provision 

 for retaining moisture is necessary, and it is a surprise to find 

 in such a habitat plants that wilt so easily. The reason for this 

 might furnish a problem worth solving by one with the time 

 for the work. 



Varying Weight of Leaves. — That a bushel of leaves 

 picked from a tree in spring weighs less when dried than a 

 bushel of leaves from the same tree picked in autumn is well 

 known. The increase in weight is due to the accumulation of 

 mineral matter in the leaf during the summer. A similar dif- 

 ference has been found by our government experts to exist 

 between the weight of leaves picked from the plant and dried 

 and the weight of similar leaves left to dry on the plant. In 

 the process of drying, part of the substance of the leaves is 

 withdrawn into the stem when they are left on the plant. Since 

 the loss of weight in leaves dried on the plant is often twice 

 as great as the loss in picked leaves this fact assumes some com- 



