286 
cluded the contour of the earth’s surface, elevation, latitude, 
longitude, the effects of living and dead soil-coverings (grass, 
leaves), the activities of plants and animals in the soil, etc.,etc. In 
the latter are included the influence of light, moisture, air currents, 
chemical composition of the soil. 
In section 2 the author takes up the discussion of « Zusammen- 
leben” and vegetable societies. For the time being I am unable 
to give a good English equivalent for the term Zusammenleben. 
By it the author wishes to indicate the interdependent relation- 
ships of plants and animals, whether organicaly united (parasitism, 
saprophytism, symbiotism, etc.) or merely in close proximity 
(such as plants and plants, animalsand plants). The author's con- 
ceptions of symbiosis (in the broader sense) are somewhat original. 
Parasitism is considered to be the most intimate association. The 
form of symbiosis met with in lichens is designated as “Helotism,” 
in which the alga is the slave. The term mutualism is made to 
apply to the occurrence of endotrophic and ectotrophic myco- 
rhiza. Nothing original is added to the consideration of epiphytes 
and saprophytes. Lianas are included under Zusammenleben, 
since they were doubtless formed by their original dependence 
upon vegetable supports. Commensalism is used as equivalent 
to plant societies. According to the modifying factors the plant 
societies are divided into the following great groups : hydrophytes, 
xerophytes, halophytes and mesophytes. Each of these divisions 
is again subdivided. These subdivisions with their special modi- 
fying factors are quite fully discussed. On p. 125 it is stated that 
‘‘ pure water has a blue color,” which seems to be an original idea. 
The greater part of the work is devoted to the discussion of 
comparative vegetable morphology and physiology in connection 
with the modifying factors. It is a complete and well-arranged 
resumé of our knowledge on the subject. In conclusion there is 
given a brief discussion of plant struggles, weapons employed by 
plants in their struggles, origin of species, etc. 
Considered in its entirety this is a most valuable recent con- 
tribution to the science of botany. It is a book which should 
be in the hands of every student. A.S. 
Flora of West Virginia. By Charles Frederick Millspaugh and Law- : 
rence William Nuttall. Field Columbian Museum, Publica~ 
