AGARICALES 461 



Gradually there is formed near the top an annular furrow and the rosettes 

 of sphaerocysts begin to appear in the interior of the stipe portion. The 

 lactiferous ducts develop in the surface of the stipe and in the context 

 of the pileus, perhaps derived from the auxiliary hyphae. At the upper 

 end of the stipe the palisade, intermingled with sharp binucleate cystidia, 

 gradually grows out over the lower side of the pileus as it expands. 

 Sphaerocysts then appear in the pileus and the lamellae begin to form. 

 Thus, in this species at least, development is strictly gymnocarpous and 

 quite comparable to that of the Polyporales. 



In Lactarius deliciosus (Maire, 1902), the diploid nucleus divides twice, 

 and immediately after migration into the spores, the daughter nuclei 

 divide a third time. Imperfect forms have not yet been observed. Only 

 inL. sanguifluus do the hyphae appear to form gemmae on short branches 

 (Rouge, 1907). 



The family includes only two genera, Lactarius, whose fructifications 

 are permeated by latex vessels and hence on wounding exude a turbid, 

 often colored liquid, and Russula, whose fructifications lack these vessels. 

 Numerous species belonging here are palatable and prized as food. 



Coprinaceae. — This family is reminiscent of the simpler Agaricaeae 

 in the structure of its fructification (Levine, 1914; Atkinson, 1916; Kueh- 

 ner, 1926). In the lower forms, the partial veil is evanescent, in higher 

 forms it is retained as a ring, and in the highest it is covered by a 

 blemmatogenous layer, occasionally by a universal veil. In contrast to 

 the Agaricaceae the pileus does not expand at maturity like an umbrella 

 but because of lack of geotropic stimulation, hangs campanulately from 

 the place of attachment at the stipe. The lamellae are thin and weak, at 

 times not over 200^ thick, often hygrophanous and subject to rapid 

 deliquescence, as is the whole fructification. In a few species, as in Copri- 

 nus comatus and C. sterquilinas, they are held apart by a thickening of 

 the rim and prevented from sticking together : in others, as C. atramentarius, 

 they are separated by large, projecting cystidia (75 to 100 per square 

 millimeter) which reach the opposite side of the interlamellar space and 

 bore firmly into the trama (Fig. 294, 1) (Buller 1910). 



The basidia do not stand, as in most other Agaricales, uninterruptedly 

 beside each other, but they are separated by numerous, regularly arranged 

 "paraphyses." They belong to the usual four-spored type; in many 

 species, as C. comatus, C. atramentarius, C. stercorarius and C. ephemerus, 

 they are constructed in two forms, one long, one short (Fig. 294, 2). 

 The significance of this dimorphism is still obscure; it is noteworthy that 

 the long basidia shed their pores earlier than the short (Buller, 1915). 



In contrast to the other Agaricales, maturation of the basidium does 

 not take place simultaneously over the whole fructification, but gradually 

 inwards from a small zone at the margin of the pileus. One can, as 

 Buller (1909), designate the general Agaricales type as the Equihymenial 



