THE STRUCTURE, DISTRIBUTION AND CULTIVATION OF THE IRIS 
The structure of the Iris flower. 
Of the three tribes into which the family of the Irideae is divided, the first is defined as having 
the style branches placed opposite to the stamens, and not alternately with them as in the Crocus. 
This first tribe is divided into two divisions, in one of which the stigma is a transverse lip overtopped 
by style crests while in the other it terminates the style branch. The Iris belongs to the former of 
these two divisions, which has in its turn two subdivisions, the one for those plants whose inner 
perianth segments are convolute, and the other for those with unrolled segments. This last subdivision 
is made up of the genera Iris, Hermodactylus and Moraea. Of Hermodactylus there is only one 
species, often known as Iris tuberosa , which differs from the true Irises in that the divisions of the 
placenta to which the ovules are attached do not meet to divide the ovary into three cells. 
The distinction between an Iris and a Moraea is to be found in the presence in the former of a 
perianth tube formed by the base of the segments above the top of the ovary. In Moraeas the 
segments of the flower spring direct from the ovary and do not grow together for some distance to 
form the tube before branching out. Even in such species of Iris as xiphium in which the tube is 
very short, it will be found that the withered flower comes away from the swelling capsule in one 
piece and that the six segments do not fall separately like the petals of a rose. It is this distinction 
between an Iris and a Moraea that makes it necessary to include among the Irises /. sisyrinchium, 
which resembles the Moraeas in so many ways and which is moreover so unlike all other Irises 1 . If 
it were not for this difference, /. sisyrinchium would be a Moraea and would form the only exception 
to the rule that Irises occur in the North Temperate Zone and Moraeas in the corresponding region 
in the South. 88 
Thus, in the Iris, at some distance above the ovary the tube branches out into an inner and 
an outer series, each of three segments, which may be conveniently named "standards” and "falls," 
although in the Juno section of the genus, the "standards” become mere horizontal projections held 
actually below the "falls.” Cf. the plates of /. alata (No. XL), /. bucharica (No. XLI) and'of /. 
Warleyensis (No. XLI I). 
* With the single exception of /. grooves, I. sisyrinchium is the only Iris with a monophyllous spathe (see 
It is moreover the only Iris whose rootstock is a corm. 
pp. 104, 232). 
