NATURAL HISTORY NOTES 
199 
August and Septennber, began searching that neighbourhood to note the occur- 
rence of the various wild flowers of the district, with the help of Fitch and 
Smith’s handbook (“ Illustrations of the British Flora.” Fitch and Smith, 
los. 6d. Publishers : L. Reeve and Co.), in which we are accustomed to colour 
from nature each flower as we find it. By dint of examining the sunny grass- 
slopes and banks in the glen of the Dargle, she found growing the lesser dodder, 
Cuscuta Epithymum (fig. 691), parasitic on marjoram, Origanum vulgare, which 
grew profusely here, and intertwining all about Anthemis Cotula, and St. John’s 
wort, Hypericum perforatum. This is an interesting observation, as Bentham 
and Hooker say (“British Flora,” p. 307), that the lesser dodder is “unknown 
in Ireland.” A botanist who has looked it up in Hooker’s “ Students’ Flora of 
the British Isles,” tells me that this plant was formerly known in Drogheda, 
Ireland. 
8, Well Road, Hampstead. Hilda Flinders Petrie. 
Late Hon. Sec. Richard Jefferies Branch. 
Knurs in Trees. — I should be obliged if the Editor, or any reader of 
Nature Notes, can tell me if any observations have been recorded on the cause 
and course of knurs. 
Brighton. George Morgan, F.R.C.S., &c. 
[In his “Disease in Plants” (1901), Professor Marshall Ward writes as 
follows : “ Burts or knauers are irregular excrescences, principally woody, with 
gnarled and warted surfaces. They are frequently due to some previous injury, 
such as the crushing or grazing of cortical tissues by cart-wheels. The excitation 
of the tissues thus wounded results in the development of shoots from adventitious 
or dormant buds at the base of old tree trunks, or in the starting of the same 
process where a branch has been broken off. The new bud begins to develop a 
shoot, but soon dies at its tip owing to paucity of food supplies to the weak shoot, 
while new buds at its base repeat the process next year with the same result, and 
each of these again in turn, and so on. The consequence is an extremely complex 
nest of buds, all capable of growing in thickness and putting on wood to some 
extent, but not of growing out in length. In course of time this mass may attain 
dimensions measurable by feet, forming huge rounded and extremely hard-knotted 
burrs, the cross-section of which shows the vascular tissues running irregularly in 
all directions, and, owing to the very slow growth, extremely dense and hard. 
The dark spots in such sections, e.g., bird’s-eye maple, are the cut bud-axes all 
fused together, as it were. On old elms such burrs are common at heights on 
the stem which preclude the assumption of any coarse mechanical injury, and 
similar structures occur on the boles of other forest trees suddenly exposed to 
light by the felling of their companions, which suggests that these epicormic 
shoots result from some disturbance due to the action of light.” — E d. N.N.'\ 
A Moss with Metallic Lustre. — In a cave, which looks as if it were 
partly artificial, and the front of which has been walled in leaving only a door- way, 
grows a moss which in spots and patches shines with a bright metallic lustre. The 
moss on closer examination looks like small scales, and in places, as if it were the 
undergrowth of a longer moss — this longer moss does not grow all over the 
whole space nor can the metallic lustre be seen all over the patch of moss, but 
only in places, and the brightest spots seem to be in crevices in the stone. I 
have brought a bit out into the house, but cannot succeed in seeing the lustre 
when the moss is removed from its native spot. Is the plant known to science ? 
and is it not of very uncommon occurence ? The place where it grows is in 
the grounds at Oakley near Market Drayton, the seat of Sir George Chetwode, 
the rock on which it grows is a light red sandstone, apparently very soft and friable. 
It would be interesting to know whether it has been noticed in other places. 
Certainly I have never heard of, nor seen anything like it before. I have called it 
a moss for I am not botanist enough to know whether it is a moss or a lichen. It 
is a very green plant and the lustre just like the green metallic lustre on the throats 
of some humming birds. C. E. Meade-Waldo. 
The Gables, Wirkswotth, August 31, 1901. 
[Tbe moss is identified by Mr. Gepp, of the Natural History Museum, as 
Schistostega osmundacea. It occurs in caverns in several places in England. — Ed. 
a.a:] 
