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Rosellinia aquila (Fr.) De Not. This species attacks many kinds of 
trees but is probably best known for its activity on mulberry roots. As 
a rule the trees are killed by the dense mycelium enveloping the roots. 
The mycelium penetrates every part of the root and is especially abundant 
in the medullary rays. When the host is quite dead the dark brown 
perithecia are found crowded together on the brownish velvety patches 
that previously bore the conidia. The conidial form of this species is 
known as Trichosporium fuscum. This is one of our most common species, 
and a description is found elsewhere in this paper. 
Rosellinia necatric (Hart.) Berl. This fungus produces a disease 
known as the “white root rot.” This species is, however, rather rare in 
this country. One of the peculiar characteristics of the disease is its 
power of attacking practically every plant with which it comes in contact. 
It is especially disastrous in vineyards, orchards, etc. Some of its more 
common yictims are vines, fruit trees, oaks, maples, beeches, pines, beans, 
potatoes and beets. 
The mycelium of this fungus travels underground and attacks the 
rootlets, killing them and gradually working its way up to the larger roots 
and from them to the body of the plant proper. Here in some instances 
it breaks through the cortex as a white fluffy mass of mycelium. Sclerotia 
are formed on the exposed parts of the infected roots, which give rise to 
dark, bristle-like conidiophores which bear numerous conidia at their 
tips. Globose swellings on the exposed portions of the mycelium are 
sometimes formed, which, according to Viala, are capable of emitting 
mycelium which forms a new plant. The ascigerous stage has been dis- 
covered by Viala, appearing only on trees that are well decayed. 
Rosellinia radiciperda Mass. This is the cause of the disease known 
as the “New Zealand write root rot” and is very closely allied to the 
fungus causing the “white root rot” of Europe, Rk. necatrixr. It attacks the 
roots of the apple, peach, pear, ete., and also such plants as docks, ferns, 
sorrel, cabbage and potatoes. Sometimes the trees are killed here and 
there, but often whole areas are swept away. 
The white filamentous mycelium attacks the roots and the Wark just 
under the ground. ‘This eventually gives rise to sclerotia which later 
produce the conidial stage. Next the mycelium becomes dark colored and 
gives origin to the black globose pycnidia containing stylophores. The 
aseigerous stage is found on dead tree trunks and stumps that have been 
dead for considerable length of time. 
