120 MIDDLETOI," FUXGl. — GATES. 



of lilanientous hyphaj, but the genera Russala and Locfurivs 

 have a vesiculose trama in which numbers of the liyphal 

 branches have swelled out, forming vesicles internn"ngled with 

 the filamentous hj'pha?. Several genera also possess latex tubes, 

 but these are especiallj'^ well developed in the genus Ladarius, 

 in which a wound causes a copious flow of " u)ilk." This milk 

 may be white, yellow, orange, blue, etc., or may change color on 

 exposure to the oxygen of the air. Many species of Lactarius 

 are edible and the flavor of L. deiiciosia^, which has a bright 

 orange milk, may be inferred from its name. 



The color, odor and taste of the flesh is also frequently of 

 importance. Some genera and species are characterized b} the 

 presence of sterile cj'stidia and paraphyses in the hymenium, 

 together with the club-shaped basidia which bear the spcres. 

 Four spores are usually borne on each basidium. 



Thus there is a great deal of variety in the structure of the 

 hymenophore. The spores also frequently show differences of 

 specific value. The genera of the Agaricaceaj are generally 

 placed in five groups, having respectively, white, pink, brown, 

 purple-brown, and black spores. The shade and depth of color, 

 however, vary a good deal within each group. Ihe size, shape, 

 and marking of the spores are also of specific importance. They 

 may be globose, elliptical, oblong, smooth, echinulate, wart}', 

 etc., and are only micioscopically visible. Their color is easily 

 seen when they fall in ([uantity or any good back ground, such 

 as white or colored paper with the proper contrast. 



In regard to the various mycelia, comparatively little has 

 yet been done to determine specific or generic characters, and 

 perhaps in most cases none such exist. In some species, such as 

 Arinillaria mdlea, Vahl., an agaric parasitic upon certain 

 conifers and frequently found growing from stumps, the 

 mycelium cc>llects into numerous parallel strands, forming cords, 

 the exterior of which becomes blackened with age. These are 

 called Rhizomorphs. They may often be found as blackened 

 cords under the bark of old trees or stumps, and were formerly 

 considered separate fungi, and called Rliizomorpha nuhcorticalis 



