ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 85 



The formation of both conidia and sclerotia is followed out with 

 care in Peziza tuherosa and sclerotiorum, and the view is confirmed 

 that there is no causal connection between the two. The sclerotia 

 always proceed from a mass of hyph^e which put out abundance of 

 shoots, and are more slender than other mycelial filaments. As soon 

 as they begin to coil and interweave, a general lateral branching takes 

 place, which gradually fills up all the air-cavities in the ball, and 

 unites the hyphse with one another. The sclerotia retain their power 

 of germination for years, if kept dry. They then put out thick 

 greyish-yellow club-shaped bodies composed of nothing but hyphse, 

 which grow by apical growth and finally become the fertile cups, the 

 apical growth ceasing at the middle, while the peripheral filaments 

 continue to grow and branch abundantly. After growth in length has 

 ceased, a layer of paraphyses is formed gradually from the middle 

 towards the margin, the asci being then formed, their formation con- 

 tinuing after the expulsion of the first spores. The ascospores, eight 

 of which are contained in each ascus, are 8 ,it broad and 12 /a long. 

 They germinate at once, and form ordinary mycelia with sclerotia. 

 In the autumn the club-shaped bodies often form secondary clubs, 

 even to several generations, which produce cups in the next spring. 

 If the clubs are covered with a small quantity of earth, they produce 

 much-branched strings of Ehizomorpha, on which new clubs appear 

 at all points. In certain circumstances the branches of the paraphyses 

 develope into receptacles with conidia ; they often make their appear- 

 ance in the cups as forerunners of the ascogenous layer. 



On the sclerotia of these two species of Peziza there often appears 

 a pycnidial form which interferes with the formation of the cups. 

 Cultivation produced no other form of this fungus, which Brefeld 

 calls Pycnis sclerotivora. The germination and formation of the 

 mycelium and abstriction of the spores are described in detail. 



With regard to other Ascomycetes, he finds the processes similar 

 in all essential points in Peziza ciharioides, Fucheliana, coccinea, and 

 aurantia, Otidea leporina, Sarcosphcera macrocalyx, Leotia lubrica, Geo- 

 glossum, Morchella, and Helvella ; except that in the last two genera no 

 conidia were observed, and in Peziza Fuckeliana the attempt was 

 unsuccessful to obtain from the Botrytis-spores perfect sclerotia which 

 developed into cups. All the above-named agree in this point, that 

 the differentiation of the hyphse into sterile and fertile takes place 

 only when the receptacle has nearly reached maturity. In other 

 forms, as Ascobolus deniidatus, JErysifhe, Eurotium, Penicillium, 

 Melanospora, and Xylaria, this differentiation takes place at a very 

 early period. In the first of these, after several generations, large 

 masses of thallus arose out of scolecites. In some instances the for- 

 mation of conidiophores precedes or accompanies that of the recep- 

 tacles ; but they may be altogether wanting. Brefeld considers the 

 so-called " pollinodia " to have no other function but that of 

 enveloping tubes ; the conidia and receptacles are therefore of non- 

 sexual origin. 



In three small Ascomycetes grown on hare's dung, one of which 

 resembled Byparohius myriosporus, the formation of the asci could be 



