THE AMERICAN BOTANIST. 17 



ists gradually turn from the description of new species to 

 a more careful study of the old ones, this list of hybrids will 

 be increased rather than diminished. Contrary to the usual 

 opinion, hybrids are not necessarly, nor even usually sterile. 



Wood-Stainixg Fungi. — Lumbermen and others who 

 have much to do with freshly sawed lumber are familiar with. 

 the fact that it is often streaked with various brilliant hues. 

 Usually the lumber takes on these colors after standing for a 

 time in piles. The colors most frequently noticed are brown, 

 black, pink, purple, yellow and blue. A recent investigation 

 of the cause of these colors at the Missouri Botanical Garden 

 brings out the fact that the staining of the wood is due to 

 various microscopic fungi belonging to several genera. In 

 some cases the stain is due to the color of the mycelium of 

 the fungus, and in others to various pigments produced "by the 

 plants. 



Protective Coverings of Plants. — The varying de- 

 grees of pubescence in plants are most convenient aids to the 

 systematic botanist in distinguishing species, but it is pretty 

 certain that this use is not the principal one for which such 

 out-growths of leaves and stems were designed. Their uses 

 to the plant are to protect from sudden atmospheric changes, 

 to facititate transpiration, or to aid in controlling it, to shade 

 delicate organs, to ward ofif dangerous insects, etc. A writer 

 in the OJiio Naturalist^ states that of about two thousand dif- 

 ferent species of Ohio plants, only one-fourth were glabrous, 

 that is, without any outgrowths from the epidermis whatso- 

 ever. Nearly a thousand plants were found to be covered 

 with some description of downy covering. A few were stel- 

 late-pubescent and fifty or more were glandular-pubescent. 

 There were nearly sixty glaucous plants in which leaf or stem 

 bears bloom similar to that which appears on ripe grapes and 

 plums. There were also about fifty scurfy and granular 



