298 
THE JOURNAL OF BOTANY 
and Labiatce (see New Phytologist, viii. p. 31; 1909). A. Ewart 
(Proc. R. Soc. Victoria, xxi. l-2il ; 1908) published a list o£ 4000 
instances, 3000 of them are from his own observation. These were 
made mostly upon a store of seeds from 600 species, found in a 
cupboard at Melbourne, which had been sent out from Kew in 1856 
for a projected botanical garden, but were never used ( New Phyto- 
log ist, 1. c.). Ewart’s experiments confirmed those of Becquerel, 
the Leguminosce furnishing more than half of the number of cases of 
longevity. In most cases these were what are known as “ hard ” 
seeds ; they do not swell in water, many Leguminous seeds being 
provided with a hard waterproof coating which must be broken before 
water can be imbibed. 
J. W. T. Duvel published two very important papers on the subject 
in Bulletins 58 and 83 of the Bureau of Plant Industry of the U.S. 
Department of Agriculture. Bulletin No. 58 (1904) is on cultivated 
seeds, and the author finds that the average life of those varies greatly 
with different families, genera, and species; some lose their vitality 
in a few months, while others retain it for years. With proper treat¬ 
ment vitality might be prolonged for many years, but never for 
centuries. Climatic influence plays a most important part in pre¬ 
serving vitality, heat with moisture quickly destroying it, while a dry 
temperate climate prolongs it. 
Duvel’s second paper (Bulletin No. 83, 1905, on the vitality of 
buried seeds) records experiments made representing 109 species, 84 
genera, and 34 families of cultivated and wild plants. He mixed each 
seed sample with dry clay soil and packed the mixtures in dry well- 
baked clay flower-pots, covering them with inverted clay saucers. The 
seeds had been harvested in 1902, and were buried at various depths 
in heavy clay soil in December of the same year. As a result of 
these experiments it is stated that wild seeds retain their vitality 
longer than those of cultivated plants, and that there are wide 
variations in the vitality of seeds of different species in the same 
genus, even amongst the wild forms. The pernicious character of a 
weed is usually proportional to the length of time its seeds remain 
viable when buried; the deeper the seeds are buried, the better is 
their vitality preserved, and hard seeds retain their vitality longer 
than soft ones. 
These researches are of great interest in relation to the problem 
under consideration. The conclusions arrived at appear to favour the 
theory that deeply-buried seeds of wild plants under natural con¬ 
ditions may retain their vitality, in some cases even for a very long 
period, not germinating until brought to the surface. It must be 
noted that in Duvel’s experiments on wild seeds, these were not sub¬ 
mitted to the natural conditions of self-planted seeds. Had this been 
done, the conclusions would have been much more convincing. 
The following unpublished observations should throw further light 
upon the problem we are considering :— 
In a garden near Birmingham there used to be bushes of TIlex 
europceus , which were pulled up about twenty years ago and destroyed; 
yet, year after year, seedlings of TIlex have come up in that garden. 
