Orton : Parallelism Between Spore-Forms 
23 
arity possessed by the urediniospores of suspected alternate species 
and proved by cultures that his presumptions were correct. 
It has been pointed out by de Bary® and others that certain 
species of Ascomycetes on which both conidial and ascigerous 
stages are known produce mycelium of “ the same qualities and 
capabilities ” from both kinds of spores. 
There is frequent allusion to this in mycological literature where 
physiological studies of the mycelium arising from the conidia of 
a species have been compared with the mycelium arising from 
ascospores of the known or suspected alternate stage. In one 
case which has come to my attention a dissimilarity in this respect 
was considered of sufficient importance to warrant keeping them 
separated. This view is certainly a safe one to follow, but no one 
yet has proved in a sufficiently large number of cases that the 
mycelia from both .<^pores are identical in a physiological test, such 
as is made in culture media, to justify final conclusions. Such an 
identity is possible and, if actual, would prove a valuable test to 
further substantiate the theory of parallelism as herein indicated. 
The following examples will serve to bring out more clearly 
what the writer has in mind. The powdery mildews show this 
parallelism in every case with which the writer is familiar. Here, 
there is in the asexual stage the production of simple, colorless, 
more or less barrel-shaped conidia corresponding almost in every 
detail with the ascospores of the connected stge. 
In the genera Rhytisma and Lophodermium, which have the 
conidial forms Melasmia and Leptostroma respectively, the same 
likeness is found. In both, the conidia and ascospores are simple, 
colorless, and cylindrical. The genus Glomerella possesses two 
conidial stages, Gloesporium and Colletotrichum^ each of which 
possesses conidia structurally similar to the ascospores of Glo^ 
merella. Still more striking is the similarity between the asco- 
spores of Ophionectria coccicola E. & E. and the conidia of its 
alternate stage, Microcera sp. Both conidia and ascospores are 
fusoid, colorless, and many-celled. (Fig. i.) 
Herprotrichia nigra has brown, two- to three-septate ascospores 
* De Bary, A., Morphology and Biology of the Fungi, Mycetozoa and Bac- 
teria (English edition), pp. 225—230. 1887. 
