306 DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



have another form of basidium, as was first observed by Tulasne. Subhymcnial 

 hyphal branches swell in these genera to a spherical or ellipsoid cell filled with 

 protoplasm, the initial or primary basidium. This cell then divides by vertical 

 longitudinal walls usually into four cells arranged as the quadrants of a sphere, 

 secondary or definitive basidia, each of which then puts out a long sterigma and abjoints 

 a spore upon it which absorbs the whole of its protoplasm. Slight variations occur 

 in the number of the secondary basidia formed from a primary. But more important 

 than these are the differences in the separation of the basidia, which may go so far 

 that before the spore-formation each of the three sister-basidia becomes separated 

 down to the base, or, on the other hand, all may remain united as at first; or again 

 the division of the primary basidium may be incomplete or be omitted, and the 

 basidium become imperfectly chambered or lobed, each division answering to a 

 sterigma ; this is the case, according to Tulasnc's account, in Tremella violacea and 

 T. Cerasi and in Sebacina incrustans, and according to Brefeld in Tremella yiolacea '. j 

 Cases of the latter kind form the transition to the two-lobed or four-lobed basidia of 

 Dacryomyces and to ordinary Hymenomycetes. 



In Auricularia Auricula Judae (A. sambucina, M.) the primary basidium is long 

 and cylindrical and very like the basidia of Dacryomyces and Calocera. It divides 

 by transverse walls into a row of four or five daughter-cells, each of which sends out 

 an erect subulate sterigma, which rises above the surface of the hymenium and 

 abjoints a spore. The sterigma issues from the apex in the uppermost basidium of a 

 row, in the rest from the side close beneath the upper wall ; the formation of 

 sterigmata and the abjunction of spores begins in the uppermost basidium of a row ; 

 the rest follow it in order from above downwards. Exactly similar phenomena are 

 described by Tulasne in Hypochnus purpureus, only the end of the row is in this case 

 hooked and the terminal cell itself is sterile. The shape of the ripe spore also is pecu- 

 liar, 'being reniform in most of the Tremellincae. These characters necessitate the 

 separation of the Tremellineae as a special division of the Hymenomycetes. The 

 gelatinous constitution of the sporophore is a convenient character in many cases, 

 but would not be of sufficient importance by itself, the more so as Sebacina incrustans 

 and Hypochnus purpureus, the latter of which I have not myself examined, do not 

 appear to have gelatinous membranes. 



By far the greater number of the Hymenomycetes form only one hymenial layer 

 on each sporophore, whether it is of only brief duration or lasts longer and even for 

 many years. The course of its development, the maturation of its parts, exhibit 

 in general the same progressive advance towards the margin and apex as has 

 been already described in connection with the growth of the whole apparatus which 

 bears the hymenium. A few slight deviations however occur. On the one hand, 

 the definitive completion and differentiation of the originally uniform elements of 

 the hymenium are effected, according to Brefeld, in Coprinus simultaneously at all 

 points of the hymenial surface ; it has long been known that in C. mieaceus and 

 C. comatus the ripening of the spores, as shown by the lamellae turning black, even 

 begins at the margin of the pileus and the edges of the lamellae and advances to the 

 middle of the pileus and the base of the lamellae. On the other hand, indubitable 



1 See particularly the Ann. d. sc. nat. XV (1872), p. 234. 



