512 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, August 17, 1858 
NOTES ON THE DEVELOPMENT OF BULBS AND TUBERS. 
By Thilo Iemisch. 
(Abridged from the German original.) 
( Continued from page 296.) 
Iris Persica , L. Iris Xiphium , L. 
The flowering bulb, which possesses at its base a small dry 
stump, the remains of the last year’s peduncle, is clothed ex¬ 
ternally with numerous very thin dry skins. These are fol¬ 
lowed from their base to the height of from one to one inch 
and a half by about five scales (Fig. 1, a), which are already 
quite dry as far as the upper margin, where they are marked 
by a scar. Then follow from seven to nine broad fleshy 
scales, whose tips are yet perfect. 
As regards the height of these, it may be remarked that the 
lower decrease gradually in length, and this decrease ex¬ 
tends from the first to the fourth or fifth; then they in¬ 
crease again in a higher ratio, so that the uppermost is the 
largest; the upper ones, however, are thinner and more 
membranaceous. Buds occur in the axils of the lower of 
these leaves whose tips are still perfect (and, indeed, though 
not so regularly, in the axils of the lower scales), and the 
size of the buds is in an inverse ratio to that of the mother 
leaves, the largest bud being found in the axil of the smallest 
scale (the third, fourth, or fifth). A rather small bud occurs 
also in the axil of the next somewhat larger scale; the axils 
of the three or four upper scales are barren. 
The axis is very short, so far as it is studded with the above- 
mentioned scales, winch alternate with tolerable regularity, 
and have no closed sheath; from this arise a few slightly- 
branched roots, piercing the base of the scales. In immediate 
continuation of this main axis rises a rather short stem (three- 
Fig. 4. 
Fig. I. 
Fig. 
Fig. 3. 
Iris Persica and I. Xiphium 
Iris Persica. 
Bulb in a state of rest. I b 
Fig. 2. 
fleshy portion of its scales. 
Iris Xipiiium* 
Bulb from which the dry 
dried portion of scales of 
bulb. 
coats have been removed, 
a. rudimentsof filiform roots. 
lug. 3. Young bulb in axil of 
highest scale, showing 
the successive scales. 
Fig. 4. Y T oung bulb in axil of se¬ 
cond and third scale, 
a, b. their sheathing scales, 
e. leaf. 
quarters to one inch and a half high), which bears from four 
to six leaves, separated by very short but perfectly distinct 
internodes, above which are two membranaceous leaves, which 
surround the terminal blossom. Blossoms also frequently 
occur in the axil of the last and last leaf but one; at the 
base of their stem a membranaceous bract is found turned 
with its back to the main axis, and at the tip of which, 
as in the terminal flower, are two membranaceous leaves. 
These blossoms often remain rudimentary, or are entirely 
abortive. 
The bulbs are formed from the above-mentioned axillary 
buds, of which, however, the lai’gest only blow the following 
year. These buds are constructed as follows:—The outer 
leaf has two angular keels ; with it in general there are at the 
most three rather membranaceous scales. Then follow three 
or four leaves which are developed at the time of the flowering 
of the parent bulb, and whose blades afterwards wither, while 
their fleshy base remains ; then follow scales. 
The arrangement of the appendages on one and the same 
axis is as follows : — 
1. About three membranous scales, which soon dry and 
invest the bulb. 
2. About five leaves whose blades perish, but whose bases 
serve to form the bulb. 
3. From seven to nine scales, which also help to form the 
bulb, and in whose axils especially buds destined to produce 
the new bulbs are formed. 
4. From four to six leaves, which are seated on the 
common flower-stem. 
5. Two membranaceous leaves, which form the in¬ 
volucre of the terminal flower. 
The transition from one to two is rather gradual, as 
also from two to three, but less so from three to four. 
While the new bulbs are forming, the contents of 
the parent bulb are gradually absorbed; it is no 
longer requisite when the former have attained their 
full growth, and it dies off completely. The ripe bulb 
is also represented by leaves (independent of the ax¬ 
illary buds) which belong to a single axis. 
The bulbs of Iris Persica differ from those of the 
Tulip, in that their main axis produces leaves (No. 2), 
from that of the Hyacinth and Lily in the short 
duration of its parts, and from that of Tigridia 
pavonia , in that the main bulb is not seated immediately 
at the base of the peduncle, but in its stead many 
other leaves. 
Iris Xiphium bears a great resemblance to Iris 
Persica in the structure of its bulbs. In a state of 
rest (at the end of summer or in autumn) the outer¬ 
most scales are dry and membranaceous, followed by 
fleshy scales, which have no closed sheath, and which 
are still perfect at their tips (Fig. 2) ; their margins 
also are not separated from one another, but that of 
tire one is wrapped for a short distance over that of 
the other, by which character the bulb of this species 
may be distinguished from that of J. Persica , with 
which it agrees in size. 
In spring from about eight to ten leaves, arched 
backwards, grow above the sheaths, which extend a 
little, so that the uppermost of them is the longest, 
and which, like the next below it, is far more mem¬ 
branous than the others which contain the nutriment, 
that is gradually absorbed. A few of the leaves grow 
at the base of the peduncle, but the others, separated 
by tolerably large internocles, are disposed on the 
peduncle, which is about a foot high, and is terminated 
by a flower, near which another breaks forth. Buds 
occur only in the axils of the scales, and not in those 
of the leaves ; the lower are smaller, the upper larger. 
Two modifications of the buds or young bulbs occur 
in cultivated specimens. The larger (Fig. 3), which 
