CARPOSPOREM, 



309 



Fig. 204.— Diagrammatic section of the fructification 

 of Ascobolus furfuraceus (after Janczewski) ; nt myce- 

 lium ; c carpogonium ; / pollinodium ; s ascogenous fila- 

 ments ; a the asci; rp the sterile tissue from wfiich the 

 paraphyses h are developed. 



a completely developed fructification, I select as an example Ascobolus furfuraceus^ 

 a Discomycete described by Janczewski. Fig. 204 represents a vertical section of the 

 entire fructification of this Fungus, whilst still 

 in connection with a portion of the mycelium, 

 somewhat diagrammatically drawn for the sake 

 of clearness. The carpogonium c and the 

 pollinodium / arise from branches of the my- 

 celium. The former consists of a row of thick 

 short cells, and is considerably curved; the 

 delicate branches of the latter become closely 

 applied to the anterior portion of the carpo- 

 gonium. In consequence of fertilisation, one 

 of the central cells of the carpogonium (which 

 is designated the ascogonium) grows more 

 vigorously than the others, assumes a some- 

 what spherical form, and developes by gem- 

 mation numerous filaments from which, at a 

 later period, the asci are developed. In the 

 meanwhile there has been formed from the 

 hyphae bearing the sexual organs a mass of 

 filaments which completely invests the carpo- 

 gonium, and which forms the large sterile por- 

 tion of the fructification. Its hyphae are so 

 aggregated as to form a pseudo-parenchyma, 



r in Fig. 204 being the cortical layer, 2i\i^ pp the internal portion, in which the sterile 

 hyphae are diagrammatically indicated. The ascogenous filaments which have sprung 

 from the ascogonium continue to grow forming a layer ss within the fructification, the 

 subhymenial layer, and send upwards thick club-shaped branches, the asci, within which 

 the spores are developed. In this way the hymenium aa \'& formed, and it is com- 

 pleted by the upgrowth between the asci of parallel branches, the so-called paraphyses, 

 from the sterile portion. Finally the cortex r gives way at the apex, the hymenium 

 comes to lie at the surface and expands in the manner represented in Fig. 205, in 

 order that the spores may readily escape from the asci. In Pe%'i%a confuens, the 

 species in which the sexual reproduction of the Ascomycetes was first discovered by 

 De Bary in 1863, the process is as follows, according to De Bary's and Tulasne's 

 exhaustive researches: — The mycelium of P. confluens grows on the ground; branches 

 arise at particular points of its hyphae which are directed upwards and again branch 

 abundantly ; at the end of the branchlets the organs of conjugation or fertilisation 

 are produced in large numbers close together, forming rosettes. The terminal cells 

 of the stronger branchlets swell up into ovoid vesicles (Fig. 206, a), which put out 

 a usually crooked prolongation (/*). From another cell of the same branch lying 

 beneath this carpogonium grows a club-shaped branchlet, the pollinodium, the apex 

 of which (z) unites with the prolongation just mentioned. After this has taken place, 

 a number of fine hyphae {h) shoot out of the filament which bears these organs, and 

 these surround the rosette of the organ of conjugation, enclosing it in a dense felt. 

 This felt forms the body of the fructification ; upon its upper side densely crowded 

 hyphae immediately rise up to form the hymenial layer ; finally the fructification becomes 

 an apothecium, which possesses somewhat the form represented in Fig. 205, and pro- 

 duces the ascospores in its asci. Woronin observed similar phenomena in P. granulosa 

 and scutellata. In these species branches consisting of three or more cells arise from 

 the mycelium; the terminal cell swells out into a globular or ovoid form, without, 

 however, putting out a prolongation ; from the cell lying beneath it arise two or 

 more slender filaments which attach themselves closely to the former. The conju- 

 gating apparatus now becomes densely enveloped in numerous hyphae which 01 iginate 



