i62 BOTANICAL GAZETTE [February 



sporogenous hyphae, or may proliferate branches of the second and 

 of higher orders, sporogenesis in the latter case being confined to 

 the terminal elements, the hyphal portions below the points of 

 attachment of branches remaining sterile. 



5. Two tendencies in the development of fructifications are 

 recognizable: one leading to an erect drendroidal type, in which 

 successively proliferated fertile elements undergo processes of 

 sporogenesis in continuous sequence; and the other leading to a 

 prostrate racemose type, in which sporogenesis is delayed in the 

 older branches until the younger branches have also attained their 

 final extension. The majority of species show these tendencies 

 combined in different ways. 



6. The sporogenous hyphae of most species are coiled in peculiar 

 spirals, sometimes resembling the spores of the hyphomycetous 

 genus Helicoon. These spirals exhibit pronounced specific char- 

 acteristics in the number, diameter, and obliquity of their turns, 

 and especially in the direction of rotation (whether dextrorse or 

 sinistrorse) . 



7. Sporogenesis, where it can be followed, begins at the tips of 

 the fertile branches and proceeds basipetally. In the larger num- 

 ber of species the process involves the insertion of septa which, in 

 certain cases, are relatively very massive, and in others so thin as to 

 be barely discernible. The disposition of these septa, while the 

 delimited spores undergo maturation processes, varies with the 

 species: (i) they may remain more or less unaltered; (2) they may 

 sufifer a median split, the two resulting halves being then separated 

 as the result of the longitudinal contraction of the young spores, 

 leaving alternate portions of hyphal walls completely evacuated; 

 or (3) they may first become considerably constricted and sub- 

 sequently converted into non-stainable isthmuses connecting the 

 mature spores. The apparent absence of septa in the sporogenous 

 hyphae of other forms is perhaps attributable to optical difficulties. 



8. Granules are readily differentiated in the spores of many 

 species which possess the staining properties and uniformity of 

 size characteristic of nuclei; they generally occur singly, but in 

 the larger spores of a few forms two are often found occup}'ing 

 diagonally opposite positions. 



