Raising Irises from Seed 235 
If it is thought that /. pallida and /. variegata will not provide all the characters found in the 
hybrid, the question arises, “What other species can have been used?" Here we are met with the 
fact that no trace of any other species except those mentioned is to be found in herbarium collections, 
if we exclude the sambucina and squalcns forms, whose origin we are trying to discover. Examples of 
these come only from long-cultivated and inhabited areas and moreover the plants are almost invariably 
sterile, under conditions in which /. pallida and /. variegata set seed fairly readily. 
Other facts, which would tend to variability in the hybrids of these two species, are that /. variegata 
is apparently liable in the wild state to produce forms in which the yellow ground colour is replaced 
by white (see p. 169), while I. pallida has produced either under cultivation or in the wild state the 
plicata forms with flowers, which are wholly white except for the lavender or purple reticulations bordering 
the segments (see p. 167). 
Another small point is connected with the pale edges, which surround the richly coloured falls of such 
hybrids as Black Prince, Iriskonig, and Darius. This seemed inexplicable until I found that among a 
large number of wild examples of /. variegata from Hungary which I have recently had the good 
fortune to see, a certain proportion have a distinctly pale, almost whitish edge. Thus no fresh species 
is required to account for this feature. 
If no list of these garden hybrids is given, the reasons are that, with a few exceptions among 
the older and well-known varieties, every collection seems to have names of its own and that improve- 
ments are constantly being obtained. 
RAISING IRISES FROM SEED 
The process of raising Irises from seed is, with comparatively few exceptions, much easier and 
much less tedious than it is usually supposed to be. Among the various divisions of the genus there 
are considerable differences in the length of the periods that elapse between the sowing of the seed and 
the time when the plant reaches flowering size. The most precocious of all Irises are the dwarf 
bearded species ; for instance, seeds of Iris putnila ripened in July have been known to germinate in 
the following spring and to produce plants that actually flowered in October in the same year. This 
is, perhaps, a somewhat exceptional instance but members of bearded and beardless species may be 
expected to flower within eighteen months of the time when the seeds germinate. 
Bulbous species take much longer to come to maturity and seedlings seldom, if ever, flower before 
their fourth or fifth year. 
It is a curious fact and one of which no explanation has yet been offered, that it is the seeds of 
precisely those species that always produce an abundance of seed that germinate most readily. For 
instance, of I. setosa, I. versicolor , and most members of the sibirica group, all of which are self- 
fertilised and of which practically every flower sets seed, every individual seed seems to germinate in 
the first spring. On the other hand, in the case of the large bearded Irises and of the members of 
the Oncocyclus group, where seed is much less readily obtained, and then only by artificial pollination, 
germination is infinitely slower and more irregular. If thirty or forty seeds, the contents of a single 
capsule, are sown at the same time and under identical conditions, it usually happens that only two or 
three germinate each year and some have been known to lie dormant and yet sound for at least 
fifteen or eighteen years and then finally to germinate. In a letter written only a month or so before 
his death, Sir Michael Foster told me that a seed of an Oncocyclus hybrid had just germinated with 
him after lying dormant for eighteen years. 
In this connection, it is noticeable that those seeds on which the aril is most marked (see Plate 
XLVIII, no. 8) are those whose germination is the most irregular. 
Another curious fact is that hybrid seeds, resulting from a cross between two species, besides being 
less numerous also germinate much less readily than those of self-fertilised species. 
All Iris seeds seem to germinate most readily in the open air and though a cold house may be 
an advantage to young seedling plants in early stages, yet thousands of seedling Irises may be raised 
with no further help than that of a cold frame. Frost and alternate frost and thaw, far from being 
harmful to dormant seeds, seem to have a beneficial action on the outer coats, although they are 
sometimes disastrous to minute seedlings. 
With regard to the period at which the seeds should be sown, a distinction must therefore be 
drawn between bulbous and non-bulbous species, unless the gardener is so fortunate as to have unlimited 
accommodation for seedlings during the winter in a cold house or well-ventilated frames. In this case, 
seedlings of non-bulbous species that germinate in the autumn can be kept through the winter though 
it is not always easy to prevent damping off. 
As a general rule, it may be taken that the seeds of bulbous species should be sown as soon as 
the capsules burst, while those of the non-bulbous species should be kept until late September or early 
October. If the seeds are sown earlier, germination will often take place about that time. If the 
seedlings are left in the open, many will be uprooted by frosts and if taken under cover some may 
damp off. Although most Iris seedlings are so hardy that, even when drawn out of the ground by 
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