Arable Land 
wait till the crop is removed, or the potato-stalks are 
rotting on the ground. 
Mr. Ridley records an unusual exactness in flowering 
for certain orchids and Dipterocarps near Singapore, 
A Dendrobium flowers with the greatest punctuality 
every six weeks. On the proper day every plant in the 
district is white with blossom, but next day one can find 
nothing but withered flowers. This habit seems also to 
be common with Bromheadias.’ 
It is really just as wonderful to find in one field, 
thistles, Scleranthus, and many other weeds, all shedding 
their seeds within exactly a day or two of one another. 
It is more difficult to explain why it is only in some 
years that almost every bamboo plant is found in flower, 
or why certain Shoreas and Hopeas should regularly 
blossom within one or two days of one another, at 
intervals of six years. 
Weeds have several very remarkable peculiarities, 
besides their ingenuity in the way of flowering exactly 
when it suits them best. Most of them possess under- 
ground runners or rhizomes or fleshy roots, which are 
placed just too deep for the plough or spade to interfere 
with them. 
Bishop’s weed, coltsfoot, thistle, bracken, and several 
others cannot be eradicated by the plough, for their 
starch-filled stems or roots are just out of reach, Even 
if one could manage to drive a cultivator through these 
roots so as to cut them in pieces, this would not be of 
much use. It has been shown that a piece of these 
runners (thistle), one quarter of an inch in length, is 
capable of producing a complete new plant, 
It is very disheartening to try and remove the thistles 
from a field by mowing them down. But it can be 
done; for, if the thistles are cut over three or four 
times a year, and this continued regularly for four years, 
257 R 
