197 
the top of the wall was scraped and cleaned by the mason’s 
trowel. He said he knew of no other locality for the plant in 
Norwich. 
I would now speak to you of a very interesting little plant, not 
very uncommon in meadows and chalky downs, which moves of 
itself and changes its place without the intervention of man. It 
is the Herminium monorchis, the specific name having reference to 
the peculiar structure of the root. In our other British species 
of the restricted genus Orchis, if dug up in the flowering season, 
you will find the root to consist of two tubers, one of which 
supplies the flower of the current year, the other being reserved 
for the year after. If you dig up the Herminiwm monorchis when 
in flower, you find but one tuber ; there are other roots, however, 
of a fibrous character, one of which gradually elongates in a 
~ horizontal direction, till after a few weeks or so the tip thickens, 
swelling at last into another tuber from which springs the plant 
of the next season, of course removed an inch or more from the 
site of the first plant. In this way, then, the plant in course of 
time may traverse a whole field ; and ultimately disappear, along 
with any other specimens in the same fleld. And this may have 
been the case to a certain extent ina field from which Broome 
and I obtained our specimens ; for, a few years afterwards, on my 
inquiring about them, he told me he could hardly find any. 
This part of my subject would be left imperfect if I made no 
mention of the plants introduced into this country, unintention- 
ally, by man or from other accidental causes, to take the place, as 
it were, of those which have been lost to our Flora. I need not 
say much as regards the Bath Flora, having spoken of it before at 
some length in a previous lecture referred to above. I may add, 
however, to that statement that there are three plants in my 
herbarium, gathered in this neighbourhood, foreigners, and not 
mentioned in any British Flora, One is a composite plant, which 
Broome, who first pointed it out to me in 1871, growing by the 
river's edge at Batheaston, said it was the Cacalia hastata, but I 
