44 



and pliloem remaining free from stain. In tbe cotton fungns the older 

 mycelium itself, inside the vessels, is frequently stained yellow or 

 brown. Browning of the mycelium of the melon fungus inside the 

 vessels of the plant has not been observed, but it occurs in pure 

 cultures on boiled melon stems, etc. Once started, in cotton at least, 

 this browning may extend long distances through the woody parts of 

 the stem with very little fungus to help it on. 



OTHER WILT DISEASES. 



This disease should not be confused with the cotton-root rot of Texas, 

 from which it appears to be distinct,' nor with another wilt of cotton, 

 cowjjeas, etc., common in parts of Florida and first described by Prof. 

 P. H. Eolfs. This is associated with a fungus which attacks many 

 kinds of plants, wild and cultivated, enveloping the base of the stem 

 externally with a copious, white, rather straight mycelium, bearing on 

 its surface large numbers of small sclerotia which are first white, then 

 fulvous, and finally dark brown and smooth. When grown on nutrient 

 media (agar), the fungus reproduces itself by another crop of sclerotia, 

 and so on indefinitely (a year in my laboratory). These sclerotia are 

 mostly 0.8 to 0.9 by 1.2 to 1.3 mm. 



RELATIONSHIPS. 



The perithecium of Neocosmospora much resembles a medium- sized 

 bright red Nectria, and if gathered in an immature condition would nat- 

 urally be placed under ISTectriella, as the spores are smooth and colorless 

 and there is no indication of any septum, even in the most elongated or 

 in very old spores. When ripe, however, the ascospores are distinctly 

 brown, and the fungus clearly belongs to a new genus. It possesses 

 some of the characters of both Nectriella and Melanospora, but is dis- 

 tinct from either. On the whole it seems to be nearer to Nectriella 

 than to Melanospora, although the spores are brown. It is not very 

 closely related to Melanospora as originally established by Corda and 

 defined in Saccardo's Sylloge Fungorum. It is widely different from 

 MelanoHpora chionea, M. leucotricJia, M. zamia', M. vitrla, M. zobelii, M. 

 coprina, M. laf/enaria, M. 2mrasitica,, and all other Melanosporas and 

 Sph.erodermas which the wiiter has been able to examine or to find 

 figured. The ascos^^ores of this fungus are particularly unlike those of 

 Melanospora. In the latter they are smooth, often lemon-shaped, or 

 even apiculate, and frecjuently obh(iue or fiat on one or both sides. The 

 general appearance of Melanospora indicates that it might perhaps be 

 properly excluded altogether from the Nectriaceous fungi, its affinities 



1 Four hundred cotton plants killed by this disease were received from two differ- 

 ent localities in Texas in 1895. Pamniel's Ozoniuni was present, bat not a trace of 

 any stage of this fungus could be found. These plants came from regions much 

 subject to root rot. 



