THE AMERICAN BOTANIST 



151 



until another morning comes, when they wilt again and this 

 time do not recover. Before the day is ended they have fallen. 



A Curious Fern Pest. — Some time ago, a friend of 

 this magazine sent the editor some fronds of the marsh fern 

 which at first glance seemed to bear its fruit dots, or sporangia, 

 in a broad band on the rachis. The fern is noted for pro- 

 ducing abundant sporangia which at maturity quite cover the 

 underside of the pinnules and it therefore seemed quite natural 

 for it to bear sporangia on the rachis to which the pinnules 

 w^ere attached, but a little closer examination revealed the 

 fact that the band of spore cases is merely the decorations, 

 as it were, of a silken cover spun by some small but cunning 

 larva for its own protection. The occurrence of such an insect 

 on the ferns has apparently not before been reported and is 

 well worth recording. 



Acids in Fruits. — Even sweet fruits have some acid in 

 them and, as everybody know^s, the sourness of other kinds is 

 due to an excess of such acids. Though there are apparently 

 a good many degrees of sourness in fruits, the acids which 

 cause them are comparatively few^ Malic acid seems to be 

 the principal one. It is, probably the only acid, in plums, 

 apples, cherries, bananas, persimmons, watermelons, peaches 

 and quinces as well as many others. In the canteloupe, lemon, 

 orange, and pomegranate citric acid is found, while in cran- 

 berries, raspberries, and blackberries both citric and malic 

 acids are present. In some cases one or the other of these 

 acids is represented by a mere trace or it may disappear 

 altogether. 



A Giant Mushroom. — Among the many fine things 

 which come to those w^ho walk in Nature's ways, are the little 

 surprises she holds in store for her true lovers. One does not 

 have to go far afield, nor seek strange places to encounter 

 them. They come like the last ounce thrown in by the gen- 

 erous dealer for good measure, though the full demand is 



