60 



ORGANOGRAPHY, 



of Fungi and Lichens, and in other cases; probably mucli more 

 frequently than is commonly supposed. The mode in which 



Fia. 142. 



Fig. 143. 



Fig. 144. 



m 





Pi"!7. 142. Yeast plant in process of development Fig.\^. Conferva 



glomerata, showing the progressive formation of ramifications (6, c, </, e) 



from its side. After Mohl Fuj. 144. Formation of the pollen in All/up.a 



rasi'.a. After Mohl and Ilenfrey. a. shows four nuclei in tlie parent cell, 

 and four septa commencing to be formed. The primordial utricle and 

 cell-contents are contracted by the action of alcohol, h. The development 

 of the septa more advanced, c. The primordial utricle removed fror» the 

 parent cell, but not yet completely divided into four parts, d. The 

 division of the parent cell into four parts completed. 



this budding occurs may be thus described. At a certain point 

 the primordial utricle appears to acquire a special development, 

 for it is seen to bulge out, carrying the cellulose wall of the cell 

 before it, by which a little prominence is produced externally 

 (^Jig. 143, b), this continues to elongate until it forms a tubular 

 l)rojcction, c, on the side of tlie primary cell. Tlie cavity of this 

 projection is at first continuous with that of the cell from whence 

 it spnin*;, but after it lias acquired a certain definite length, its 

 primordial utricle becomes constricted at the point of contact 

 with tbc primary cell, d, and ultimately forms a partition be- 

 tween them, as in the ordinary ja-ocess of cell-division. In some 

 cases, as in the fi^rmation of tlie fibrilliform cells of Fungi and 

 Lichens, no jjartitions are formed but all the branches commu- 

 nicate with each other (fig. 10). This process of cell-divisiou 

 is termed gemmation or budding. 



2. Cell-division ivilh absorption of the trails of the parent cell^ 

 and tlie setting free of the new cells. — The ]>ollon cells in the 

 anthers of all Flowering IMants, and the sjiores of most Flower- 

 less Plants, are formed by this i)rocess. The manner in which it 



