6 4 



DIVISION I. GENERAL MORPHOLOGY. 



said ; in Calocera and Dacryomyces they are cylindrical thin-walled cells rich in 

 finely-granular protoplasm, which either entirely fills their inner space or is interrupted 

 by vacuoles. It may be assumed that there is a nucleus always present, though in 

 the smaller forms it has been looked for in vain up to the present time. Where 

 it has been observed, as in Dacryomyces, Calocera, Corticium calceum, and especially 

 in the basidia of Corticium amorphum (Fig. 30) which become mm. in length, 

 it is a spherical weakly refringent body (perhaps the nucleolus), lying in about 

 the centre of the cell. It is not to be seen in the early states of the basidium, 

 and it disappears when the formation of sterigmata commences. More exact 

 investigation into its behaviour in spore-formation has yet to be made. When the 

 basidium has reached its full size, the sterigmata make their appearance on its rounded 

 apex as narrow subulate sprouts, and when they have arrived at a certain length their 

 extremity, which up to this time is finely pointed, swells into a vesicle which gradually 

 acquires the form, size, and structure of the mature spore. As the spore advances 

 to maturity the protoplasm of the basidium passes into the swollen extremities, 



FIG. 30. Corticium amorphum, Fr. Development of the spores, the successive stages being in the order of the letters. 

 a a nearly mature basidium with cell-nucleus, f basidium with two ripe spores, two others having already dropped off. 

 Magn. 390 times. 



and at length, when the spores are nearly matured, the delimitation of them by cross 

 septa takes place ; the basidium has by this time given up the largest part of its 

 protoplasm, but retains a thin parietal layer and is still turgescent. A clear central 

 spherical portion may be distinguished in the young fresh spores of many species ; 

 it remains to be determined whether this is a nucleus and has proceeded from 

 the nucleus of the basidium. 



The point of abjunction of the spore is either exactly at the apex of the sterigma 

 or a little below the apex at a bend turned outwards (Fig. 30), so that the spore 

 when detached takes with it the apical portion of the sterigma as a short stalk, or in 

 a few cases, as in Bovista and some species of Lycoperdon, abjunction occurs at the 

 point of insertion of the sterigma, which is consequently attached as a long stalk to 

 the spore when the latter becomes free. In the cases mentioned above, where there 

 are no sterigmata, abjunction as far as is known takes place in the way described. 



Arthrobotrys (Fig. 21) will serve as an example of another form belonging to this 

 category. 



