58 FUNGI. 
The hymenium is, however, the most important part, con- 
sisting of (1) the paraphyses, (2) the asci, and sometimes (3) 
an investing mucilage. The asci are always present, the para- 
physes are sometimes rare, and the mucilage in many cases 
seems to be entirely wanting. 
The paraphyses, which are formed at the first commencement 
of the receptacle, are at first very short, but soon elongate, and 
become wholly developed before the appearance of the asci. 
They are lincar, sometimes branched and sometimes simple, 
often more or less thickened at their tips; almost always they 
contain within them some oleaginous granules, either coloured or 
colourless. Their special function seems still somewhat obscure, 
and Boudier suggests that they may be excitatory organs for 
the dehiscence of the asci. However this may be, some mycolo- 
gists are of opinion that, at least in some of the Ascomycetes, 
the paraphyses are abortive asci, or, at any rate, that abortive 
asci mixed with the parapbhyses cannot be distinguished from 
them. 
The mucilage forms itself almost at the same time as the 
paraphyses, and previous to the formation of the asci. This 
substance appears as a colourless or yellowish mucilage, which 
envelopes the paraphyses and asci, and so covers the hymenium 
with a shining coat. 
The asci appear first at the base of the paraphyses, under the 
form of oblong cells, filled with colourless protoplasm. By rapid 
growth, they soon attain a considerable size and fulness, the 
protoplasm being gradually absorbed by the sporidia, the first 
indication of which is always the central nucleus. The mucilage 
also partly disappears, and the asci, attaining their maturity, 
become quite distinct, each enclosing its sporidia. But before 
they take their complete growth they detach themselves from 
the subhymenial tissue, and being attenuated towards their base, 
are forced upwards by pressure of the younger asci, to, and in 
some jnstances beyond, the upper surface of the disc. This 
phenomenon commences during the night, and continues during 
the night arid all the morning. It attains its height at mid-day, 
and it is then that the slightest breath of air, the slightest 
