DIVISION I, GENERAL MORPHOLOGY. 



The septum appears first as an annular ridge on the inner side of the lateral wall 

 of the basidium, and grows slowly into a plate of considerable thickness which is 

 convex on the side towards the basidium and correspondingly concave on the other, 

 and shows the bluish lustre of gelatinous membranes under the microscope. When it is 

 fully formed the apex of the basidium elongates to form a new gonidium. The 

 new portion thus formed is close under the transverse septum. In correspondence 

 with the subsequently rounded form of its apex it is from the first somewhat 

 narrower than the septum, and by its elongation it separates the septum at its 

 margin from the lateral wall of the basidiurfl and carries it upwards with the goni- 

 dium to which it belongs. Each gonidium accordingly has its slightly convex 

 surface resting at first on its younger sister with the margin free, but attached to 

 its apex by the broad middle portion. The gelatinous cross septum, to which 

 the whole of the surface of attachment belongs, is continuous above with the lateral 

 wall of the gonidium ; and while this becomes slightly thickened as it developes, 

 a membrane, which is not at first clearly defined, is formed on the inner surface 

 of the septum and is also continued into the lateral wall which it resembles in 

 appearance ; this is the persistent basal wall of the goni- 

 dium. At the same time the original gelatinous transverse 

 septum begins to disappear from its margin inwards as if it 

 melted away. There is now in all beyond the third and 

 fourth youngest gonidia of a row only a quite narrow in- 

 termediate piece in the middle connecting each with its 

 younger sister. This piece is of about the same height as 

 the original septum, but the bluish glistening substance in 

 it dwindles from below upwards into a small plate which 

 becomes continually thinner and remains attached to the 

 wall of the gonidium to which it belongs. As this process 

 goes on the intermediate piece becomes pale and very 

 slightly refringent, and after persisting for some time in 

 this state at length disappears. There is no reason for 

 regarding this delicate intermediate piece as a part of an 

 outside membrane which covers the whole gonidial chain 

 like a sheath, as I formerly did. The single gonidia show 

 no important changes after they are detached from the 

 gonidiophore beyond the thickening of their membrane 

 already mentioned, which cannot be further pursued here. 



Most of the propagative cells formed by acrogenous 

 abjunction which have now been mentioned are detached 



by abscision in the manner described above, and, like the cells of Sprouting Fungi, 

 they must become detached by disappearance of an original intermediate lamella 

 just as is observed in Cystopus. Careful examination shows indications of this in 

 almost all cases,- but the details of the proceeding are often difficult to follow on 

 account of the too small size of the parts, yet it can be seen very distinctly, in spite 

 of their small size, in the successive gonidia-rows in Eurotium and Penicillium, not- 

 withstanding their minuteness (Figs. 35 b and 36). Some further details may be seen 

 in Zalewski's treatise, mentioned at the end of this chapter. 



In a certain number of forms the separation is effected by the formation of a 

 gelatinous or gum-like deliquescent substance both on the surface of separation 

 and on the rest of the circumference of the spore. It must be supposed that this 

 substance also is the product of an outer lamella of the spore-membrane which 

 was not originally gelatinous; but the minuteness of the objects prevents this from 

 being certainly ascertained. With the ordinary amount of moisture necessary for 

 the growth of Fungi the deliquescent substance absorbs so much water that the 

 spore when abjointed is easily detached ; a drop of water washes it away at once, 



FIG. 36. Penicillium glancum. 

 a young gonidiophore with the com- 

 mencement of successive serial ab- 

 junction of spores, plunged while still 

 alive in water. 4 single sterigma from 

 an older gonidiophore bearing a row of 

 spores, after treatment with alcohol 

 and glycerine. Magn. 600 times. 



