16 THE AMERICAN BOTANIST 



tected by an epidermis of sufficient thickness. One has but to 

 recall the typical sun plants of the tropics to see that all of them 

 have coarse heavy foliage from which moisture does not read- 

 ily evaporate. 



Stones Moved by Plants. — It is well known that plants 

 have had a share in shaping this planet rending the rocks by 

 means of their roots and dissolving the particles of soil by the 

 acids they excrete, but cases in which plants actually contri- 

 bute to the building of the land by carrying stones seem little 

 known to the botanist. That this actually occurs is vouched for 

 by Shaler who reports certain "rolling beaches" near Cape Ann 

 to be due entirely to this action of plants. It seems that along 

 certain coasts where the bottom consists of small stones, var- 

 ious sea-weeds grow, finding the stones to which they are 

 firmly attached desirable for anchorage. When storms occur, 

 however, the waves drag both the sea-weed and stones away 

 from the bottom and cast them up on the beach. Here the 

 sea-weed speedily dies, and the stones are added to the beach. 



Lath Plant Houses. — Glass houses for the protection 

 of plants during the colder parts of the year are too common 

 to be remarkable, but houses for protecting plants from the 

 heat of summer are still so rare in some sections as to be 

 curiosities. A few years ago when the cultivation of Sumatra 

 tobacco was being tried out in New England some entire farms 

 were covered with cheese-cloth screens under which the crop 

 was cultivated. Everybody cannot afford a greenhouse and 

 many of those who can do not wish to be bothered with the 

 care of one but anybody who owns a garden can have a plant 

 house for protecting the delicate woodland species. It is built 

 out of common laths nailed to any sort of supporting frame- 

 work the laths being separated an inch or so from one another. 

 In such a house, the early spring wildlings linger a long while 

 after their sisters in the fields and woods are gone since they 



