MISSOURI BOTANICAL GARDEN BULLETIN 65 
species of iris which grow from a small bulb and require a 
treatment not essentially different from that employed with 
tulips and other spring-flowering bulbous plants. The 
Spanish iris is an example of the latter type, whereas the 
: apanese and German irises are examples of rhizomatous 
orms. 
Cultivation.—Irises are native to, and very widely dis- 
tributed in, the north temperate zone, no species having been 
found south of the equator. Our own climate, therefore, 
is well adapted to the growing of irises and the very gener- 
ally successful growing of these plants indicates that their 
culture is not attended with any serious difficulties. A few 
suggestions as to cultivation may, however, prove service- 
able. Irises in general are sun-loving plants; a few species 
thrive in half shady localities, and even the so-called German 
iris and certain others will live in shady situations but 
flower more profusely when removed to sunny exposures. 
Those species known as “Pogonirises,’’ which have a dis- 
tinct beard on the “falls,” usually grow best on a heavy, 
well-drained limestone soil, exposed to abundant sunshine. 
Those forms known as “Apogon irises,” which have no 
beard on the “falls,” or at most only a very slight pubescence, 
do better in a light alluvial soil rich in humus. During the 
winter irises should not stand in water, in fact an abund- 
ance of water is necessary only just before and during the 
_ flowering period. After the Ligouiee season, most irises 
appreciate a period of rest, a condition which is usually best 
induced by withholding the water supply. The Japanese 
irises, however, do not require this period of rest and to this 
group other individual species could be added. 
The selection of the proper habitat for irises, especially 
as regards the water supply, is, as indicated above, import- 
ant and it is fortunately possible to differentiate between the 
dry and wet-soil species es the fact that the leaves of the 
latter, when held up to the light, show a number of minute 
blackish spots, whereas those of the former pr uniformly 
green. In dealing with new plants it is obvious that this 
character may be extremely serviceable in indicating the 
proper choice of soil and position — the presence of the spots, 
for instance, always indicating that the plant is a native 
of marshy ground. 3 
The usual practice of moving perennials in the fall should 
not be extended to the iris. At this time the main roots 
have already produced their lateral branches and these are 
broken or injured in the removal, and the plant does not 
subsequently make good progress. The principal roots grow 
