XXVIII.— THE YELLOW FLAG. 
Iris Pseudacorus Linne. 
T HE considerable Family Iridace <e includes few plants which are applied to useful 
purposes but many valuable in our gardens from the beauty of their flowers. 
It is chiefly extra-tropical, South Africa being its chief centre at the present day ; 
but the genus Iris belongs rather to the North Temperate Zone. While varying 
considerably in floral form, the plants of this Family agree in being perennial and 
herbaceous, mostly with fleshy underground stems and relatively long and narrow 
leaves often equitant, two-ranked, that is, conduplicate, or folded down the midrib, 
and with both margins of one outside those of the next, as if astride of them. 
In all, the perianth is superior and petaloid, consisting of six floral leaves in two 
whorls ; whilst there are but three stamens. These alternate in position with the 
perianth-leaves of the inner whorl, but not with the carpels. In other words, the 
three carpels are said to be superposed on the stamens, an anomaly which appears to 
be accurately explained by the suppression of an inner staminal whorl. The stamens 
are epigynous and their anthers burst outwards. The three-chambered, many-ovuled 
ovary is surmounted by a simple style, which expands above into three more or less 
petaloid branches ; and the resultant fruit is a three-sided capsule, which splits 
longitudinally and loculicidally, i.e. through the midribs of the constituent carpels. 
While the genus Crocus has six similar perianth-segments, in Iris and Gladiolus 
the two whorls are dissimilar ; but, whilst Gladiolus is monosymmetric, Iris is 
polysymmetric, though the large petaloid extremities of its styles make it appear a 
somewhat puzzling flower for the tyro. Its inflorescence, technically known as a 
rhipidium, or heterodromous uniplanar unilateral cyme, certainly is complex. The 
flowers are produced, in succession, on short stalks in the axils of large sheathing 
bracts or spathes, which are green with membranous margins. If the second flower 
springs from the right-hand side of the base of the stalk of the first with its bract 
facing the two flowers, i.e. with its hollowed side towards them, the third flower will 
spring from the left-hand side of the base of the stalk of the second with its 
bract facing the other way, i.e. with its concavity towards that of the other bract. 
Similarly, the fourth flower springs from the right of the third, the fifth from the 
left of the fourth. This alternate branching is termed heterodromous ; whilst as each 
branching is on one side only, it is unilateral ; and, as all the flowers succeed one 
another in one plane, it is uniplanar. 
The perianth forms a short tube below, and within it the nectar is secreted. Its 
three outer leaves or sepals are large and spread outwards and downwards, narrowing 
below into a channelled stalk-like portion. These “falls,” as they are called by 
gardeners, have in many of our cultivated species a central “beard” or fringe of 
hair-like processes ; but this is not the case with either of our wild British species. 
The petals are smaller and are also narrowed below with inrolled margins ; but, as 
they stand nearly erect, they are known as the “ standards.” 
