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257
ON SOME RUSTS AND MILDEWS IX INDIA.
By a. Baeclay, M.B., Bengal Medical Service.
(Plate 298).
It is somewhat remarkable, considering the economic importance
of the subject, that no systematic study of the Busts and
Mildews of our cereal crops in India has ever been undertaken.
The following notes on some of these may therefore be of interest
for although this paper contains nothing absolutely new to science,
an accurate record of the occm-rence of these fungi in India must
be interesting to the student of geographical distribution, and to
scientific agriculturists.
In a recent paper submitted to the Asiatic Society of Bengal, I
recorded some observations on the prevalence and characters of
Bust and Mildew on wheat, and I have therefore excluded this
from the present paper. This latter subject is one of the greatest
importance ; but our information concerning its Ufe-history is still
so meagre and incomplete, that it is premature to enter upon it. I
will only note here that, so far as I have been able to gather, the
most prevalent form of Bust on wheat, barley, and oats in India is
Piiccmia Paibigo-vera DC, and not P. (iraminis Pers. And this is
true even of the outer Himalayan region, where Bust is very prevalent,
and where three species of barberry are common {B.
Lycium Boyle, B. aristcita DC, B. vnhjaris L.), one of which, B.
Lychim, bears an iEcidium abundantly. At the same time I have
never been able to find an .Ecidium on any species of Boraginefe in
the Himalayan region, and none is known on the plains. "Whilst P.
Piubigo-vera is apparently by far the commonest Bust in India,
P. (/raminis is not wholly unknown. I have received specimens
of P. graiitinia from Jeypore, about 200 miles in a direct line from
the nearest known habitat of barberry ; but I have never seen a
specimen on the crops actually in the neighbourhood of ^cidiumbearing
barberry. These facts are suflScient to show the mystery
in which the subject here is involved, and that it needs much more
study before anything useful can be -ss-ritten on it.
The fungus on Linum (" Ulsee") is apparently extremely common
over large areas of the plains. It is often so closely concurrent
with Bust on wheat and barley, that the uredo stage on Linum has
often been supposed to be the cause of the Bust on wheat. This
supposition, however, cannot be entertained, with our present
knowledge, by botanists. The fungus on Linum is probably a
complete autcecious species.
With these few introductory remarks I pass on to a description
of the Busts with which I am accjuaiuted in India, other than
those on wheat, barley, and oats.
Puccixu SoBGHi Schw. on Surghum vulgare Pers. (" Jowari").
Through the kindness of Mr. J. A. Baines, CS., 1 obtained
some specimens of rusted Sorghum from the Bombay Presidency.
Journal of Botany.—Vol. 28. [September, 1890.] s