82 MISSOURI BOTANICAL GARDEN. 



branch alternately from the mycelium. These first conidia 

 are borne in clusters of three types, two of which are 

 simple clusters of the type of those of Sporotrichum but 

 not borne on prostrate hyphae, the other being a form 

 which is like most of the conidia described under Cera- 

 tostomella. In this latter form the conidia are borne in 

 the short branching chains. These conidia are all ephem- 

 eral and do not hold their vitality as long as those which are 

 produced later upon the heads or stromata. In order to 

 distinguish them from the latter, they are now for the first 

 time called secondary conidia ; and those of the heads or 

 stromata are now called primary conidia. As the colony 

 grows older, some portions of the mycelium become more 

 or less pigmented, and the darker filaments grow together 

 in masses from which erect columns of parallel hyphae 

 spring forth. These bear heads composed of branched 

 hyphae, which produce the primary conidia terminally by 

 abstriction. As fast as the conidia are formed they drop 

 away into a mucous matrix which forms over the surface of 

 the head. 



Secondary Conidia. 



The secondary conidia of the /Sporot)'ichum-type are of 

 two forms and are borne on simple erect or branched 

 hyphae. The first form of this type are attached to the 

 hyphae in spreading, open clusters, which do not fall to- 

 gether in masses until some days after they mature (pi. 7, 

 f. 3). The second form are produced in close clusters 

 which fall together as rapidly as they mature (pi. 9, f. 9). 

 The third form of fruiting, as mentioned in the previous 

 topic, more nearly resembles the branching chains of the 

 conidia of many species of Ceralostomella (pi. 9, f. 3). 

 The spores in all three forms are oval, elliptical, or cylin- 

 drical, and correspond closely in form and measurement to 

 the primary conidia of the same species. They are unicel- 

 lular and formed by abstriction either from the terminus of 

 the hyphae or from short, terminal or lateral branches. 



