370 BOTANICAL GAZETTE [june 



''When highly magnified they have a very delicate light green color. 

 This color is quite distinct, and it seems strange that of many observers 

 Alwood (1894) seems to be the only one to recognize this greenish 

 color." Looked at with the microscopes commonly used, corrected 

 for two colors alone, the spores do have a greenish tint- Spores were 

 examined with all the different types of microscopes in the Cornell 

 University laboratory, and with one exception, the Zeiss apochromatic 

 lenses, they showed a greenish tint; but with these lenses, which are 

 corrected for three colors, the spores are absolutely hyaUne; so we 

 must return to the original conception of the color. 



The spores as a rule have one nucleus, though I have occasionally 

 seen two in very large spores. The nucleus appears as a rather large 

 clear area near the center of the spore and generally close to one wall. 

 It is generally clearly seenj though in old spores, or in those beginning 

 to germinate, or in poorly developed spores, it is sometimes not yisible. 

 This structure has been noticed by nearly every investigator, but so 

 far as I have found, it has not been recognized as a nucleus. It is 

 spoken of as a ''clear hyaline area," a ''round spot not granular as the 

 rest," a ''vacuole," etc. Studied in stained sections, however, its true 

 character appears. It takes the nuclear stains readily, though it is 

 difficult to distinguish the structure. In some of the related forms, 

 as Myxosporium corticoliim^^ large oil drops are sometimes present in 

 the spores, which may be confused with the nucleus, but the latter is 

 distinguished by its lighter color. Oil drops are highly refractive, 

 presenting a slightly greenish tint with the ordinary microscope, while 

 the nuclei do not show it. The nucleus in the conidium is consider- 

 ably larger than the one directly below in the conidiophore. 



As yet the perfect stage of many of the anthracnoses is unknown, 



but the ascospore form of several has been found recently. In some 



it has been found several times; but in others it has been found one, 



two, or at least only a few times. This may be due to the fact that the 



ascospore forms are rarely developed, or that the investigators have 



overlooked them, perhaps on account of their rarity or inconspicuous 

 nature. 



WTiile the conidial stage of all the forms is very similar, yet even 

 m the few forms worked out they are connected with at least three 



3 Myxosporium corticolum Edgerton. Ann. Mycol. 6: 4^-5 2. 1908. 



