474 
JOHN A. ELLIOTT 
4. Of these spores, all globular, sarcinaeform, cubed, or oblong 
spores without apex or beak belong to Stemphylium. 
5. Macrosporium, by priority, becomes the name of the genus which 
has been known as Clasterosporium Schw. 
6. Of the four species described by Fries when he created the genus 
Macrosporium, two belonged to Alternaria and M. tenuissimum 
(Nees) Fries becomes the type of the genus Macrosporium. 
7. In these genera, conidiophores and conidia possess the only 
suitable characters upon which to describe species. 
8. Conidia in many species go through secondary changes which 
destroy their distinctive characters. 
9. Secondary changes in conidia may be due to age or to abnormal 
environment. 
10. The genus Mystrosporium was described from Alternaria in 
advanced secondary development. 
11. Mycelial characters are too easily affected by external condi- 
tions to be dependable in describing species. 
12. Slight changes in media may cause great changes in the sub- 
merged mycelium. 
13. Identical changes of environment may bring about opposite 
reactions in different species. 
14. Morphology of the dependable stable characters under normal 
conditions is the most useful basis for describing species. 
15. Due consideration must always be taken of the age of the 
organism in describing a species. 
16. For convenience, the genus Alternaria should be divided into 
groups of species having similar spores. 
The writer takes this opportunity to express his thanks to Pro- 
fessor F. L. Stevens for encouragement and many helpful suggestions 
in carrying out this work; to Professor Wm. Trelease for aid in solv- 
ing the taxonomic problems involved; and to others, mentioned or 
not mentioned in this paper, who have given assistance in any way. 
University of Illinois, Urbana. 
LITERATURE CITED 
1. Bauk, H. Zur Entwickelungsgeschichte der Ascomyceten. (Pleospora her- 
barum.) Bot. Zeit. 1877: 313-326. 
2. Berkeley, M. J. Notices of British Fungi. Ann. Nat. Hist, i: 261. 1838. 
3. Bioletti, F. T. Some Diseases of Olives. Calif. Agr. Exp. Sta. Rep. 1895: 243. 
4. Constantin, M. J. Sur les Variations des Alternaria et des Cladosporium. 
Rev. Gen. Bot. i: 453-466. 1889. 
