59i 
Went. — Notes on Sugar-cane Diseases. 
have a rectangular form and are colourless ; sometimes they 
are slightly coloured and more oval, approaching in their form 
the macroconidia. Fig. 20 gives the tops of three hyphae 
bearing microconidia ; in a the upper part is empty, the 
microconidia having been shed ; in b there is one conidium 
just escaping from the hypha ; in c two microconidia are not 
yet pushed out. 
Macro- and microconidia may be found on branches of the 
same mycelium filament. In making cultures of macroconidia, 
both forms of conidia are obtained, just as well as when 
cultures are begun with microconidia ; proving that they 
belong to the same fungus. Lastly, all sorts of transitory 
stages between the two forms of conidia may be found : as 
in Fig. 21, where a and b represent two stages in the typical 
formation of a chain of macroconidia, whereas in c it can be 
seen that the lowest of these macroconidia is being pushed 
out of the hypha in which it has been formed, just like 
a microconidium. The size of the microconidia and that 
of the macroconidia too (but in a less degree) is extremely 
variable, so that the measurements given here are only 
approximately true; macroconidia 16-19 x 10-12 /x ; micro- 
conidia 10-15 x 3*5-5 M ; length of the microconidia-bearing 
hyphae j 00-200 \l. In order to give an idea of the difference 
in form and size of the conidia I have delineated in Fig. 22 
a group of conidia, as I found it under the microscope. 
Though I made a great number of cultures of this fungus 
I could not detect other organs of reproduction ; the same 
result was got by Wakker, who also has been cultivating the 
fungus at Pasuruan for some years. The microconidia of 
the fungus are similar to those described by Zopf for Thielavia 
basicola 1 , but the macroconidia are very different. I therefore 
have given the fungus the generic name of Thielaviopsis and 
call the species in question Thielaviopsis ethaceticus , 
It may be easily proved that Thielaviopsis ethaceticus is the 
cause of the pineapple-disease, by bringing some of the conidia 
1 W. Zopf, Ueber die Wurzelbraune der Lupinen, eine neue Pilzkrankheit. 
Zeitschrift fur Pflanzenkrankheiten, Bd. i, 1891, p. 72. 
