360 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
I can only find two faults in it. It is so large, and it costs so much ; 
but both of these are occasioned by its virtues. The life-sized portraits 
of Irises are very beautiful, and require every inch of its dimensions 
so as to avoid that sad example of defaced beauty, a folded plate. 
There are forty-six of these full-page coloured plates of representative 
or little-known species, besides two others showing various forms of 
seeds and roots. 
If perfection were possible in a monograph, there should be a coloured 
figure of every species and variety of the plants described; but with 
such a genus as Iris this would mean several large volumes, and we 
must be grateful for the number of original plates in this, and also 
for the clear way in which attention is called to figures in other books. 
This is done by an asterisk preceding the references to descriptions 
in other works that are accompanied by a figure, both under the 
accepted name and also in the list of synonyms. 
The ample margins, and the arrangement of lists of authors, 
synonyms, and localities in columns, make it wonderfully easy to 
find any required reference. The reader is further assisted by the 
use of the same sequence of parts of the plant in the description of 
each species, and the commencement of a fresh line for each heading. 
In many cases outline drawings are given in the text, showing the most 
important characters. 
But the greatest value of the book is due to the fact stated in the 
introduction, that the writer " refused as far as possible to take any- 
thing for granted," and instead of being content to copy the state- 
ments of local floras, he determined to examine all the available 
herbarium specimens, and whenever possible to cultivate the plants 
himself. The book is therefore rich in original observations, useful 
to the systematic botanist and also to the cultivator of plants for 
the sake of their beauty — a rare combination in a book of such 
importance ; for it is seldom that so clever a botanist and so ardent 
a gardener are combined in one personality to form so good an 
author. 
He tells us, for instance, that the moisture-loving Irises, Iris hexagona 
and I. fulva, must be grown in hot and dry places to be induced 
to flower freely in England : that there are two distinct forms of 
I. ruthenica, of which one flowers well and the other is a very miser of 
its blooms. 
Another of his discoveries is so useful and interesting that I quote his 
words : " Nature has provided us with one infallible sign which will show 
us whether an Iris is a native of a dry or a wet soil. This will be 
seen if leaves of /. Psendacorus or /. versicolor are held up to the 
light side by side with a leaf of a Pogoniris ; for instance, of /. germanica. 
The latter will appear of a uniform green, but the former will show a 
number of minute blackish spots, which on microscopical examination 
prove to be due to the fact that at these points the vertical channels 
in the tissue of the leaves are blocked by growths of apparently the 
same structure as that which surrounds the passages. The increased 
