108 The Botanical Gazette. [March, 
formed distortions, whole shoots are transformed. 18 pe 
the season the Exobasidium forms only slight local ee 
tions on the leaves, and still later one finds forms w : 
do not distort the tissues of the host plant at all, but simply 
form a scurf on the lower side of the leaves. The same pe 
cession is found in the forms on Andromeda down to fe ; 
mentioned, to which my attention was called by Dr. W. . 
Setchell at Woods Hole, Mass., late in the month of A 
It was also found up to early September in Newport, ‘“ 
This form, which appears as simply slight whitish spots ’ 
under side of the leaves, has not been definitely con M4 
the others as yet by means of cultures, but the spores an ‘ 
dia are the same as those of the other forms on And -4 
This being the case it would appear that, in peri : 
Vaccinii at least, the form and extent of the hyper 
pends both on the host and the age of the tissues ie" 
The older tissues do not respond so readily to the ie : 
of the parasite, and the result is a more local hypertrop se 
none at all. Differences of these kinds may be ey 
than is generally recognized, and where, in the simpler 10f" 
of fungi, the distortion plays an important part in ae 
distinctions only actual experiment with living a o 
determine whether two closely similar species are really 
tinct or not. 
Cambridge, Mass. 
XPLANATION OF PLaTE VI. 
= zs moe i of wall of distortion of Exobasidium — 
on romeda ligustrina. x 210. aa 
igs. 2-9. Venous ies in the development of the basidia 
spores of E. Andromedz. x 550, 
ig. 10. Mature and germinating spores of same. X 55°- 
Fig. 11. Conidial spores of same. 5 60. 
s 
: x 
Fig. 12. Distorted parenchyma cel lows the center of the gall 
210. dromeda le! 
Figs. 13-14. Basidia and spores from infection of An 
with E. Andromedz. xX 550. ‘ dromeda led 
Figs. 15-16. Basidia wee, spores from infection of Andr 
with E. Vac inii. E inii oD Ap 
ig. 17. Outline of distortion produced by E. Vaccl 
dromeda leaf. x 10, 
ig. 18. Same produced by E. Andromedz. x 10. 
Fig. 19. Same collected in the field. X 10. in the felt 
Fig. 20. Same of E. Vaccinii on Gaylussaccia collected i - 
1-16 
ceprrinee 
Seer ea ee a Ee ee. 
xs ‘All of the figures reduced about ¥% in reproduction. Figures 
drawn with the aid of an Abbé camera. 
lifolia at sie! 
**The writer collected a form similar to this on Andromeda po 
bourne, N. H., in June, 1894. 
