422 
NATURE 
[June 17, 1915 

articles, the text figures of fungi and insects are 
numerous and on the whole well-executed. 
The genus Crataegus, which reaches so con- 
spicuous a development in the States, has been 
carefully worked up by Prof. Sargent, and some 
nine hundred species are now recognised, to the 
confusion of European botanists and gardeners. 
In the encyclopedia the account of the genus occu- 
pies nearly eleven pages from the pen of Mr. 
Rehder, and the key to the fifty species which 
he mentions lends considerable value to the 
article. Eucalyptus again, another enormous 
genus but this time of introduced plants, occupies 
twelve pages, and there is a large illustration of 
a very fine specimen of E. viminalis growing in 
California. The key, which refers to as many as 
seventy-six species, is followed by short, useful 
descriptions with a few text-figures interspersed. 
Other large genera which fall within the compass 
of this volume are Cereus, Dendrobium, Echino- 
cactus, Echinocereus, and Euphorbia, all of which 
receive very careful treatment. 
There are a certain number of full-page illus- 
trations, either in colour or in the form of photo- 
graphic reproductions, which are well executed; 
among the latter that of cranberry-picking in a 
New Jersey bog makes a delightful picture; the 
coloured plates might have been dispensed with 
as they are of no particular interest. It is diffi- 
cult to find any plant of importance or value which 
has been omitted. 
material included, the volume is unduly bulky, 
and like other American publications suffers from 
its weight. 
(2) “Forage Plants and their Culture” comes 
from the master-hand of the agrostologist in 
charge of forage-plant investigations of the United 
States Department of Agriculture, and is a valu- 
able and well-illustrated agricultural handbook. 
The introduction deals with forage crops gener- 
ally, and in connection with the legumes an ac- 
count of root nodules and nitrification is given. 
The chapters which follow treat of the preserva- 
tion of forage and choice of crops, in which the 
results of feeding experiments, chemical analyses, 
the chemical composition as affected by the state 
of maturity of the crop, and other particulars are 
given. 
The chapter on ‘‘Seeds and Seeding”? is illus- 
trated by useful plates showing the noxious weed 
seeds found among farm seeds. ‘‘ Meadows and 
Pastures” and statistics of forage crops occupy 
the two next chapters. These are followed by de- 
tailed accounts of various crops, such as timothy, 
blue grasses, meadow grasses, the bromes, the 
sorghums, millets, and other grasses which figure 
Owing to the large amount of ! 
course of study. 
assertions, such as ‘‘the endodermis.. . 

the United States. Among the legumes, alfalfa 
or lucerne occupies the first place, and the various 
clovers, peas, and vetches, soy beans, and other 
sub-tropical leguminous plants are discussed in 
some detail. 
Root crops also come in for their share of atten- 
tion. The book is written for the agriculturists 
of the United States, but the information it con- 
tains should prove of value to agricultural 
workers in South Africa, Australia, parts of 
northern India, and British East Africa, where 
many of the forage plants mentioned in the book 
can be successfully grown. 
(3) A text-book which is said to contain only the 
essentials of the subject and written for “college 
teachers’’ may well be an uninteresting produc- 
tion, and that by Profs. C. E. and E. A. Bessey 
cannot be considered inspiring. It is to be hoped 
| that the teachers who will use the book have 
already had their interest in botany roused and 
{ their enthusiasm for the subject fired by other 
teachers before taking up ‘“‘the essentials” as a 
Not even the illustrations lend a 
helping hand, as they are singularly poor, and 
those of nuclear division are almost childish. 
Though largely a very elementary treatise, the 
chapter on the chemistry of plants, with its masses 
of formule, is a formidable affair, and is too con- 
densed to be of much practical value. The latter 
part of the book consists of a rapid classificatory 
survey of the vegetable kingdom with poor little 
figures. The book should not meet with much 
popularity on this side of the Atlantic. 
(4) Mr. Horwood’s second volume follows simi- 
lar lines to the first one previously reviewed in 
Nature. The introduction gives a rapid review 
of general botanical information which is not 
always sound; the statement on p. 8, for instance, 
that if the nucleus is damaged the plant dies, 
| would suggest to the uninitiated that a plant pos- 
sesses only a single nucleus. Other sweeping 
is gravi- 
perceptional,” that parasitic plants possess root- 
hairs, and that “the protection of the stomata 
from being clogged is ensured by the provision of 
hairs and their occurrence on the under-side of 
the leaf,” may be received with caution by those 
who have a wider knowledge of botanical facts. 
Mr. Horwood, after mentioning that “very 
little free nitrogen is obtained from the air by 
plants,” proceeds to remark on the temperatures 
favourable to plant growth, and apparently with- 
out having made his calculations from Centigrade 
to. Fahrenheit, states that the “most suitable tem- 
perature for plant growth is about 28° C., though 
plants can grow below this,” and further, ‘“‘above 
prominently among the valuable forage plants of | a temperature of 56° C. plants usually die.” This 
NO. 2381, VOL. 95] 
