CHAPTER III. — SPORES OF FUNGI. 85 



exact knowledge on this point. When the spores are ripe a considerable quantity of 

 protoplasm richly interspersed " ith vacuoles still remains in some species, as Sphaeria 

 Lemaneae *, S. Scirpi and Sordaria fimiseda ; in most cases, however, the residue is 

 but scanty, but in all without exception the inner surface of the membrane is covered 

 by an unbroken though often very thin layer of protoplasm. The chief portion of the 

 contents of the ascus surrounding the spores consists of an apparently watery fluid. 



The membrane, which when young is always delicate and not stratified, increases 

 in thickness as the ascus matures, but often shows no signs of being divided into 

 layers even in such large asci as those of Morchella esculenta, Peziza Acetabulum, 

 P. pitya, P. melaena, and Ascobolus furfuraceus ; in some species, especially in Lichen- 

 fungi, it is distinctly stratified, and in a number of cases, which will be noticed more 

 fully below, it has peculiar local thickenings at the apical extremity. It shows the 

 reaction of Fungus-cellulose in most Fungi ; yet a dilute solution of iodine produces a 

 blue colour in not a few caseg, either over the whole of the ascus, as in most Lichens 

 and in Peziza convexula, P. cupularis and others 2 , according to Coemans in some 

 species of Ascobolus also, or only at the apex of the ascus, as in some instances which 

 will be considered at greater length in the sequel. 



The ejection of the spores from the asci is either simultaneous or successive. 



The simultaneous ejection of spores is much the most common, occurring in 

 nearly all the Discomycetes, in the Erysipheae, in some Sphaeriaceae and in the sporan- 

 gia of Protomyces. Certain special modifications are said to occur in Lichen-fungi and 

 will be noticed again further on ; but except in these cases the ejection of the spores 

 is due to the same mechanical arrangement as that which causes the abjection of the 

 spores and sporangia of Empusa or Pilobolus. It has been carefully observed (with the 

 exception of the case of Protomyces which must be at present disregarded) in club- 

 shaped or ovoid asci which are broader towards their free extremity and contain four, 

 eight, sixteen, or more rarely a larger number of spores. After the spores are matured 

 the ascus with its parietal layer of protoplasm enclosing a constantly augmenting 

 quantity of watery fluid expands considerably and becomes more turgid. The 

 expansion may amount to five-fourths or four-thirds or even to twice or several times 

 the original diameter of the ascus, i. e. the diameter at the time of the ripening of the' 

 spores, and takes place in the direction of the length as well as the breadth, affecting 

 especially the upper and apical portion of the ascus. That the membrane of the 

 ascus is almost entirely passive in this extension and continues to be perfectly elastic 

 may be proved at any time by cutting it through or by extracting the water. 



When the ascus begins to expand the spores move into its apical region, where 

 they are closely packed together in the watery fluid and in the simplest and most 

 common case are arranged in a single longitudinal row, the uppermost member of 

 which is close beneath the apex ; it is more unusual for them to form two or more 

 irregular rows, as in Ascobolus and its allies. In some cases gelatinous appendages 

 which will be described by-and-bye, serve apparently to keep the spores in their 

 relative positions in this arrangement or at least to assist in doing so 3 . According to 



1 Woronin, Beitr. III. 



2 See also Nylander in Flora, 1865, P- 4^7- 



3 Zopf in Sitzgsber. d. Berliner naturf. Freunde, Feb. 17, t88o. Zopf's last work on this subject 

 (Zeitschr. f. Natnraw. 56, Halle, 1884) could not be consulted. 



