284 
Review . 
and so on. The chief features in the re-vegetation of the beaches 
are summed up by the following “ reduction of the field notes to a 
history of the strands or zones emersed during each year of the 
recession of Salton Sea.” (1) The lake rose quickly to its maximum 
level and receded quickly. (2) The infiltration and leaching of the 
soil varied year by year as affected by the concentration of the 
water on one hand and the time of submergence on the other. 
(3) The salt content of the water, least during 1907, increased by 
18 to 20 per cent, in each succeeding year. (4) Each emersed 
strand would therefore be saturated with a soil solution resulting 
from the infiltration of lake water of the concentration and 
composition prevalent in the period preceding emergence. (5) The 
desiccation of the emersed strands would proceed at a rate 
determined by the character of the soil and by the composition of 
the infiltrated water. (6) The rising water of the lake picked up 
seeds lying on the surface, and their survival constituted a means 
of re-vegetation, chiefly of the strand bared in 1907. (7) The rates 
of evaporation and of recession of the lake varied with the season, 
the total evaporation being estimated at 116 inches per year, while 
the average rainfall was 2-74 inches per year. (8) Rapid recession 
of the water would result in separating stranded seeds quickly from 
the margin of the water, and rapid desiccation of the surface layer 
of soil, which would be unfavourable to germination and survival. 
(9) The shallow water lying on mud flats fringing the shores was 
raised to a much higher temperature (15 n to 20° F.) than the body 
of the lake, even during the winter season, thereby greatly increasing 
its toxicity for seeds, seedlings and propagating bodies generally ; 
most of the seeds falling into the lake would be subjected to this 
action. The muddy flats fringing the shores at all stages of the 
lake must therefore be considered as a barrier which would be 
crossed by a plant carried out into the lake and again when deposited 
on a beach. 
Details are given of the invasion of the strands formed from 
1907 onwards, and the behaviour of the invaders. Most of the 
plants invading the strands were carried there as seeds by the wind, 
by flotation, or by birds. Observations on the subsequent behaviour 
of the vegetation of the strands during the succeeding years up to 
1913, with special reference to such topics as the influence of the 
lake on the vegetation of the dry slopes above its level, the 
endurance and survival of seeds and plants, the biological and 
physical conditions of dissemination and reoccupation, the flotation 
and germination of seeds, the processes of succession and elimination, 
and the reoccupation of emerging sterilised islands, make up the 
remainder of this interesting chapter. 
Dr. MacDougal and his collaborators are to be warmly con¬ 
gratulated upon this valuable scientific study of a set of phenomena 
which gives opportunity for the investigation and discussion of so 
many topics of ecological importance. 
F.C. 
