NATURAL HISTORY NOTES 
99 
Ivy on Trees. — I can quite endorse Mr. George Rooper’s observations as to 
the trees at Watford which are ivy-covered and which certainly do not seem to 
have suffered in any way thereby. I have one or two photos, of some of these 
trees in early spring, which I am having reproduced in a forthcoming work on 
natural history, specially to illustrate the beauty of ivy-covered trees, and to show 
that it is fallacious to condemn the “parasite” — if such it can be called — for its 
liking for growing on trees. I trust that Selbornians in various parts of the 
country will do what they can to have ivy-covered trees preserved, as during this 
season of the year nothing is more captivating than the luxuriant ivy clusters 
around old and ^ea///t^-looking trees. 
.9/. Albans, Herts, W. Percival Westell, M.B.O.U. 
February 1 5, 1 90 1. 
Mr. Daubeny’s quotations on the whole appear to confirm my view. The 
Rev. Mr. Millard is, like others, “ convinced against their will, of the same 
opinion still.” I would only remark on his argument that “ little or much, the 
ivy must rob the tree of a portion of its sustenance,” that the roots of a tree 
occupy some hundreds of square feet, the ivy, the roots of which run down pre- 
pendicularly, a few inches only. It is fed by the water that runs down the trunk, 
reaching the “ tap-root ” only, the mainstay of the tree, but not otherwise 
affecting it. The mischievous error — for error it is — has its origin in the con- 
fusion of “cau.se ” and “ effect.” “ Non quia fast hoc, ergo propter hoc.” 
I cut down five trees lately, all for some years dead. Three were coveted 
with ivy, two bare. There was not the slightest difference in their measure- 
ments. A tree dies, having ivy running up it, and being dead, the ivy 
under the influence of light and air, now for the first time admitted, 
grows luxuriantly and overtops the branches. A casual observer at once attri- 
butes the death of the tree to the pernicious action of the ivy. Mites in a 
cheese, maggots in a carcase, are not the cause but the result of decay. 
March 11, 1891. George Roofer. 
A Shropshire vicar writes: — “I admire ivy on trees immensely, and have 
always encouraged it ; but about four years ago a horse-chestnut died^at our gate — 
a tree with a diameter of 2 ^ feet — and a variegated sycamore (2 feet in diameter) 
of the same age is about dying. I tried to save its life by having all the ivy 
stripped off, but it has never recovered much and still looks very unhappy, and 
the branches are dying off. Both are unquestionably killed by the pressure of the 
ivy all massing around them. At the same time I cut through with a saw the ivy 
on two other sycamores, but the ivy continues to flourish nearly as well as before. 
I (lid it to save their lives 1 My experience is that it does not injure oak. There 
are numbers of oak trees in the neighbourhood covered with it, and apparently 
uninjured. I am much interested in the ivy question, as I like the ivy on trees 
so much, and it does so well here.” 
Twining Plants. — I should be obliged for information respecting two 
opposite habits I have observed among plants which climb by twining without 
tendrils, one class turning from left to right, the other in the contrary direc- 
tion. In the former class I have noticed jasmin, convolvulus and runner beans ; 
in the latter, hop, woodbine, bryohy and climbing buckwheat. Is any reason 
known for this variation, and has a distinctive name been assigned to either habit ? 
Dartinotith. Observer. 
[The fact of some species being dextrorse and others sinistrorse is well known. 
It is connected with the direction in which the shoot circumnutates and is constant 
in each species. Careful observations might, perhaps, lead to the discovery of 
left-handed varieties of the dextrorse species, and vice-versd, as we have in the 
shells of mollusks. To say it is connected with the spiral or circumnutatory 
growth of a centric organ is not, of cour.se, to explain the “ why,” but only the 
“ how.” — Ed. N.N.'\ 
SELBORNE SOCIETY NOTICES. 
Annual Meeting. — Attention is again called to the notice in Nature 
Notes for April, with reference to members willing to assist with the loan of 
exhibits. 
Members requiring tickets should apply at once to the local Hon. Sec., or in 
