244 Annual Report of the Consulting Botanist for 187G. 
importance to notice the habit this plant has of rapidly increas- 
ing by means of its prostrate rooting stems or stolons. Each 
fragment of such a rooting stem becomes an independent plant,, 
and no amount of ploughing or other labour can clean a field,, 
short of its entire removal by manual labour or its destruction 
by fire. 
Other weeds are more dangerous from their seeds, like the 
spurrey (Spergula arvensis), which injuriously overran the 
ploughed lands of a member in Durham. Notwithstanding all 
his care, it continued to increase. This little worthless annual, 
too often overlooked because of its insignificance, produces an 
enormous amount of small, hard black seeds, which ripen all 
through the summer. Nothing but the destruction of the plants- 
as they come into flower, and before they can produce seed, can, 
get rid of them. 
Yet other weeds keep their ground from the possession of 
perennial roots or underground stems, such as the Colchicum 
autumnale, meadow Saffron or Sagons, with which some light 
gravelly soils in Yorkshire are entirely overrun. It is necessary, 
as I have advised, in such cases to dig out the whole plant, if 
the land is to be thoroughly cleaned. 
The seeds which have this year been examined by me have 
been on the whole satisfactory, if I except some samples of gras3 
seeds offered to a member of the Society by a Farmers' Supply 
Association. The packet of permanent pasture seed was pro- 
bably the worst which has ever passed through my hands, for 
though it was clean, it was very light in weight, and only 10 
per cent, of the grains germinated. It deserves the considera- 
tion of such Societies, and of individuals purchasing large quan- 
tities of seed, whether the purchase should not be made subject 
to examination by a competent person, in the same manner as 
artificial manures are bought, subject to chemical analysis. 
From the various experiments which I have made on behalf 
of members of the Society, I am satisfied that the chief injury 
done through seed is due to the mixing of old seed, which has. 
lost its power of germination, with the new and good seed. The 
length of time during which the vitality of seeds persists is. 
a most important inquiry to the agriculturist. Some are very 
short lived. It is stated, for instance, on good authority, that if 
the seeds of the willow get thoroughly dried they will not ger- 
minate ; while, on the other hand, some seeds, especially such 
as are enclosed in a thick, firm, and indurated outer covering, or 
episperm, have persisted for years in a living state. An authentic 
and interesting case of long continued vitality was that of the 
seeds of the sacred lotus {Nclumbium speciosnm) which Robert 
Brown germinated after they had been a hundred years in the 
