MUSHROOM GILLS. 



Mushroom gills, or lamelljo, anatomically considered, are composed, 

 tirst, of a central portion, a prolongation of the bymenopbore or flesh of 

 the cap, more or less dense, sometimes so thin as to be scarcely per- 

 ceptible ; second, the hymenium or sporo-bearing membrane covering the 

 surfaces of this prolonged bymenopbore. Tliey are vertical, simple, 

 ecjual, respectively, or more frequently alternating with shorter gills. 

 They are often evanescent and putrescent, sometimes liquefying alto- 

 gether. Their color is usually ditterent from the upper surface of the 

 cap, not always similar to that of the spores borne upon them, at least in 

 youth ; with age, however, they usually assume the color of the mature 

 spore. The cliange of color of the gills according to the age of the plant 

 is very important in the study of the Agaricini ; it accounts for the white 

 gills of certain species in youth, the pink in maturity, and the brown 

 when aged. 



The end of the gill nearest the stalk of the plant is termed the pos- 

 terior extremity ; the opposite end, the anterior extremity. In most of 

 the Agaricini the gills are unequal. Some extend from the margin to 

 about half the space between it and the stem ; others are still shorter. 



THE VOLVA. 



The volva is a membrane which envelops the entire plant in embryo, 

 giving it the appearance of an egg. It originates at the base of the 

 mushroom and furnishes it, during its foetal life, with the means of sup- 

 port and nourishment. Its texture is so delicate that it generally disap- 

 pears, leaving very little trace of its existence on the adult plant. In 

 many of the volvate species this organ exists only so long as they are 

 under gi'ound, and some mycologists restrict the term '• volvati " to such 

 only as retain it afterwards. As the young plant expands it breaks 

 through the top of this volva or wrapper, and, emerging, carries with it 

 patches of the membrane on the upper surface of the cap. These are 

 more or less prominent, numerous, and thick, sometimes irregularly dis- 

 posed, sometimes regularly in the form of plates, warts, etc. At the base 

 of the stem of the mushroom the remains of the volva are seen in the 

 form of a sort of wrapper. This is more or less ample, thick, and ascend- 

 ing. It is called free when it is loose or easily detached from the stem, 

 and congenital when it cannot be separated from it without laceration. 

 In some species it is distinctly membranous, and in others floccose, and 

 friable in character, sometimes appearing in ridges as a mere border, at 

 others broken up into scales, and, as the plant matures, wholly disappear- 

 ing. The volva is a feature of great importance in the study of the 

 Agaricini, of the sub-generas Amanita, Volvaria, etc. 



THE MUSHROOM VEIL. 



The veil is not a constant feature in the Agaricini, at least it is not 

 always visible. When present it consists of a membrane which extends 

 from the margin of the cap to the stem, veiling or protecting the gills. 

 This membrane, called the cortina, has given its name to a numerous and 



