SCIENTIFIC SUMMAKY. 
305 
Floridese wMcIi it contains, descriptions of new species are interspersed, and 
one of these is from our own coasts. The specimen was communicated to 
the author by Mrs. Griffiths, under the name of Nitophyllum and is 
here described in full. — [This note was crushed out of the last Number of 
P. S. K] 
The Yellows ” of the Peach. — This is a disease very common in American 
plants, and which may not be unknown to our gardeners at home. It has been 
ably investigated by Mr. Thomas Taylor, Microscopist to the Department 
of Agriculture at Washington, U. S. A., who tried a great many experi- 
ments on the leaves in carrying out his researches. The following is the 
result of his analyses of healthy and unhealthy leaves. 
Healthy. 
Unhealthy. 
Moisture . . 
. 29-20 
36-9 
Organic matter 
. 63-22 
59-4 
Ash .... 
. 7-58 
3-7 
100-00 
100-0 
He then observes that the fact of the absence of ash or solid matter, and 
of the increase of moisture in the unhealthy leaves, would of itself account 
for their greater tendency to mould. Since leaves do not absorb earthy matter 
from the atmosphere, it is evident that the cellular structure of the tree has 
in some way failed to perform its functions ; for, had the ascending sap 
carried with it potash, lime, or other earthy matter, the leaves would have 
been stored with them, since the leaves have no power to evaporate them. 
The deficiency of earthy matter in the leaves may also account for the 
absence of ash in the fruit. If the theory is well founded that the leaves 
elaborate juice for the growth of the fruit, the leaves being deprived of 
proper nourishment, the fruit cannot mature. It has been long observed 
that trees affected with the yellows fruit earlier and mature prematurely, 
and soon decay. The presence of a larger amount of sap in the unhealthy 
than in the healthy, indicates an earlier and greater flow than in that of the 
healthy tree. The presence of watery sap in the leaves, twigs, and buds, 
would induce naturally an early growth of fi’uit and premature decay. 
From these and other observations the disease seems traceable to the body 
of the tree or roots. Applications of washes in this case to the leaves 
would probably prove useless, but if applied to the bark and roots, might 
prove curative ; and for that purpose, judging from microscopic observa- 
tions, he would recommend the frequent application of hot lye as the best 
substance. 
The Variations of Plants. — This subject has been well illustrated by Mr. 
Thomas Meehan, at a recent meeting of the Philadelphia Academy of Science. 
He says that in a handful of specimens gathered in an afternoon’s walk, he 
found the following marked variations : — In regard to the spur, which is 
generally as long as the main portion of the corolla, some have them only one- 
third or one-fourth as long ; and in one instance the plant bears flowers entirely 
spurless. Dr. James Darrach, a member of the Academy, informs me that he 
believes he has, in years past, gathered a spurless form, but has neglected to 
place it on record. Then some plants bear flowers with spurs thick, and 
others with narrow ones j and while some have spurs quite straight, others 
VOL. XII.— NO. XLYIII. 
X 
