A New Species of Monochaetia. 191 



van-ing \igour. Luxuriant cultures were obtained on media 

 prepared with extracts of prune, Scots pine, and potato and on 

 the standard lemco-peptone medium. Media made with extracts 

 of Douglas fir and ash only produced thin limited growths, 

 consisting of dehcate intenvoven h\-phae. Cultures made on 

 bread soaked in the various extracts produced luxuriant cultures 

 which never bore fructifications. 



The mycehum is at first white but within a week assumes a 

 coral-pink colour. The hyphae (fig. 5) are of variable thickness 

 from i-5-3'5/Li, hyaline in the earHer stages of growth, with 

 granular protoplasm and no ob\ious inclusions or vacuoles. 

 Cross septa are numerous and the h\"phae are freely branched; 

 in many cases a septum is not present at the point of insertion 

 of a branch. The septa are commonh^ found at about a distance 

 of S /i apart but the elongating terminal cell ma}- attain a length 

 of30/x. 



The assumption of the coral-pink colour is associated with 

 two changes in the mycehum: (i) the development of stout 

 thick- walled hyphae which contain aggregations of pink material 

 in the cells (fig. 5, a) and (2) the appearance of strands of medium- 

 sized h\-phae with a parallel arrangement which take on a pink 

 colour as a whole (fig. 5, b). The connection, if an}', between 

 these two phenomena, hcis not been determined. 



Fructifications usually appear on the cultiues after about 

 ten days. The first indication of their development is the 

 appearance of a minute dark mass shghtly below the upper 

 surface of the mycelium. A fructification always appears at the 

 point of infection of the medium and is generally accompanied 

 b\- a number of others scattered irregularly over the culture. The 

 central fructification being usually the first to mature is, on 

 dehis^cence, a conspicuous feature (fig. 7). Development is verv 

 rapid and shortly after the dark masses have appeared a black 

 shining drop is seen on the surface above each fructification 

 indicating that dehiscence has commenced. This drop consists 

 of a mass of extruded mucilage containing spores. The addition, 

 or even the close proximity, of water causes a rapid change; 

 the spores flow apart with great rapidity and only remain loosely 

 held by the diffuse mass of thin mucilage. This will likewise 

 occur, after a time, in an untouched culture. The fructifications 

 produced on culture media agree generally in structure with those 

 found on the leaves (fig. 6) ; the spores, however, are larger 

 measuring 25-32 x S-io/x with stalks S-25/x long and seta 

 10-50 yn. 



The extruded spores, if undisturbed, soon germinate. About 

 three weeks after inoculation of the culture a bright pink tuft 

 of mycehum is produced apically on the spore mass from the 



13—2 



