The Retention of Vitality of Moss Protonema. 143 
No previous record has been made of a resting moss-protonema 
of this nature. Goebel 1 has described certain resting buds, developed 
from the protonema, which on being provided with suitable conditions 
for growth give rise directly to a leafy stem; but this appears to be 
a condition quite different from that described above. 
The only other resting state in mosses which has been recorded 
is still more different, for here buds produced on a leafy stem 
become arrested in their development, lose their chlorophyll and 
assume a dark brown colour. These changes appear to be produced 
as the result of unfavourable conditions of growth, and under proper 
conditions the buds develop either directly or by the formation of a 
secondary protonema into perfect plants. 2 
Moss spores contain chlorophyll and are usually very short¬ 
lived, though in a few cases spores have been known to retain 
their vitality for months. Hence the power to produce a resting 
protonema-filament which is able to resume growth, even after half 
a century, is a great asset to the piant in preventing its extinction 
through adverse climatic conditions. 
The Barnfield soil when first removed from its sealed bottle in 
1912 was found to contain 10% of water 3 ; but during the three 
years which elapsed before these cultures were set up a gradual 
drying of the soil had taken place, through the cotton-wool plug 
with which the bottle was closed, until the soil contained only 3‘3% 
of water. These percentages of water are too low for a protonema 
to exist in a vegetative condition, and it is certain that the resting 
filaments have been lying dormant for nearly half a century in the 
condition in which they are now found in the soils. The resting 
filaments have thus retained their vitality during a period of forty- 
two years in a soil containing only 10% of water, and a further 
period of three years in which the soil was gradually drying until it 
contained only 3’3% of water. 
In conclusion, I desire to express my thanks to Professor G. S. 
West for suggesting this very interesting subject for study, and to 
Dr. E. J. Russell of the Laboratory, Harpenden, for his help in 
providing me with fresh samples of soil from the original bottles. 
1 Goebel. “ Das Prothallium von Lycopodium inundatum.” Bot. Zeit., 
1887, p. 161. 
2 Campbell. “ Mosses and Ferns,” 1905, p. 190. 
3 I am indebted to Dr. T. Goodey for this figure. 
The Botanical Laboratory, 
Birmingham University. 
