BKPORT OF THB STATE BOTANIST. 135 



In very young plants the cap is hemispherical or almost 

 globose and the gills are concealed. Such plants of this and 

 of the closely related Horse mushroom have received the 

 name "button mushrooms," and are preserved in brine or 

 other liquid and sold in the leading grocery stores. As the 

 cap expands the veil separates from the margin revealing 

 the delicate-tinted pinkish gills. When mature the cap is 

 very broadly convex or nearly flat. It is generally a little 

 silky with close-pressed fibrils, but these often vanish with age 

 and the cap appears quite smooth. Its margin, especially in the 

 younger plants, extends a little beyond the exterior extremity of 

 the gills. The color of the cap is commonly white, but with age 

 it may become a little tinged with dingy hues. The flesh is 

 white, but sometimes exhibits a tendency to become slightly 

 tinged with red when cut and exposed to the air. Its taste is 

 mild and pleasant. The epidermis is separable from the cap. 



The gills are closely placed, rounded at the inner extremity 

 and not attached to the stem. The beautiful pink hue of their 

 early state gradually becomes darker and finally changes to a 

 smoky brown, which, in dried specimens, becomes almost or quite 

 black. This peculiarity in the coloration of the gills is so unlike 

 anything known in the dangerous species that it seems surpris- 

 ing that any such should ever be mistaken for this mushroom. A 

 whole group of pink-spored species, some of which are suspected 

 of being hurtful, have pinkish-colored gills, but they never assume 

 dark-brown or blackish hues. 



The stem is generally shorter than the horizontal diameter of 

 the cap and about equal in thickness from top to base. The cen- 

 tra.1 portion is a little softer in texture than the external part. 

 A collar encircles it in the upper part. Sometimes this is so thin 

 and slight that scarcely any vestige of it remains in old plants. 



The spores are sometimes described as purplish-brown but I 

 have never been able to see any decided purple tint in them. 

 They are not as dark as seal-brown but approach it. 



This mushroom, like many other plants that have been long 

 and extensiveiy cultivated, has developed into several forms 

 which exhibit quite well-marked distinctive features. One of 

 these, called the Garden mushroom. Variety hortensis, is repre- 

 sented by figures S and 9. It is often found in cultivation and 



