302 
THE JOURNAL OF BOTANY 
White Clover, Fool’s Parsley, ancl Yellow Rattle,” some of which 
still occurred in the pasture. Very few of the species retained their 
vitality, and these included Ranunculus acris and Polygonum Con¬ 
volvulus , which might well have deposited their seed quite recently. 
The research is interesting as showing that probably most of tbe 
surface-soil of our countrv contains an abundance of dormant seeds of 
some kind or other. Birch seeds were numerous, and, as the nearest 
birch trees were a quarter of a mile away, their presence gives rise to 
the question “ how did they get there ? ” Had the birch trees 
sprinkled the whole surrounding area to a distance of over a quarter 
of a mile with their wind-carried seeds ?, or were the seeds conveyed 
to this particular field by the agency of farm animals, which had 
previously been pastured near birch trees P 
Dr. Winifred E. Brenchley (Rothamsted Experimental Station) 
has published (Journ. Agric. Science, ix. part 1, 1918) a full and 
careful research on “ Buried Weed Seeds,” dealing with the germi¬ 
nating capacity of seeds contained in soil under natural conditions and 
at different depths. Samples were taken, with every possible pre¬ 
caution against error, from old pasture, pasture originally arable, and 
arable lands. Conclusive proof was obtained that seeds of Veronica 
hedercefolia had retained their vitality after lying buried for ten 
years; and there was evidence that other seeds had survived burial 
for at least 58 years. The number of viable seeds obtained from one 
field, calculated from an average of the samples taken, amounted to 
]7 millions per acre. Further information upon buried weed seeds 
will be found in Dr. Brenchley’s book “ Weeds of Farm Land,” and 
in the forthcoming work “ Manuring of Grassland,” which, she tells 
us, gives an analysis of the herbage of grassland after manuring for 
over sixty years, and which contains references to the earlier work 
on the same areas at Rothamsted of Lawes, Gilbert, and Masters. 
Ewart has also made observations upon seeds buried below exist¬ 
ing forest vegetation in Australia, and has found some at 18 inches 
below the surface which had retained their vitality (New Pliyt. /. c.). 
It is well known that when heavy clay fields are fertilized by 
spreading cbalk over them, a chalk flora appears; but if quick-lime 
be used instead, it frequently happens that a crop of white clover 
makes its appearance (Pratt, Flowering Plants of Great Britain, i. 
p. 127 ; 1873) ; and practical farmers have told me that a crop of 
trefoils follows the treatment of fields with basic slag. Neither burnt 
lime nor basic slag can contain seeds, hence the inference is that the 
seeds originated from previous crops of white clover and trefoils. 
It has been put on record that land reclaimed at Holderness at 
the mouth of the Humber yielded spontaneously a good growth of 
grass with an abundance of white clover within 3 years after en¬ 
closure (Proc. Inst. Civil Engineers, xxi. p. 454). 
Much suggestive information concerning the distribution of seeds 
and the “peopling of new soil” will be found in Warming’s CEcologr/ 
of Plants , 1909, pp. 349, 352, 303 ; but space does not admit of 
further discussion of this important topic. 
