INTRODUCTION. 13 



The spores are always arranged in a more or less 

 definite mass, or tuft, called the spore-cluster, or spo- 

 riferous nucleus. Each spore is formed of a single 

 cellule, with a transparent membrane, and containing a 

 nearly solid mass of a dark-coloured starch-like sub- 

 stance [endochrome) , which, on being expressed, breaks 

 up into impalpable granular dust. There are two kinds 

 of spore-clusters. In that which is found in the most 

 perfect Orders of the series, the nucleus consists of a 

 tuft of jointed necklace-like fibres [spore-threads) , which 

 radiate in all directions from a central point, or grow 

 from & placenta lodged in a conceptacle. The spores are 

 developed in the cells of the spore -threads, one or seve- 

 ral on the same thread, but only one in each cell. " In 

 the less organized families," writes Dr. Harvey, " the 

 nucleus is formed either from a single mother-cell, from 

 several detached mother-cells, or from such cells imper- 

 fectly joined together in moniliform strings issuing from 

 a central joint, or growing from the placenta of a con- 

 ceptacle. Each mother- cell, which is at first filled with 

 a homogeneous endochrome, becomes by repeated cell- 

 division converted into a cluster of spores, at first re- 

 tained within its walls; afterwards, on the bursting of 

 the wall, dispersed. Thus, by the evolution of one cell, 

 ,a favella, or simple globose nucleus, containing many 

 angular spores within a hyaline periderm, is formed. 

 By the evolution of several detached, but adjacent, mo- 

 ther-cells, a favellidium, or compound favella, results ; 

 and by the similar evolution of the cells of the monili- 

 form series, the highest form of favellidium is produced. 

 In all these cases the general nucleus, as well as the par- 

 ticular nucleoli, is surrounded by a gelatinous or sub- 

 membranaceous hyaline periderm, derived from the cell- 

 walls of the transformed cells." 



