Fritillaria imperialis and persica help

Jim McKenney
Fri, 06 Jun 2014 16:34:05 PDT
Any discussion of bulbs and bulb anatomy is hampered by the
lack of agreement among those conducting the discussion about what the term
bulb really means. For my purposes in what follows, a bulb is a modular mass
made up of a growth bud surrounded by fleshy storage tissue, both of these
connected to what is often called the basal plate. I’m not going to use the
term “basal plate” but instead I’ll call it the “perennial stem” of the plant.
With that in mind, bulbs have two sets of stems: the annual stems which emerge
from the ground and on which any  leaves,
flowers and seeds formed by the plant develop. In those bulbs which produce
roots from the annual stem (many lilies do this) it helps to distinguish
between the annual roots and the perennial roots. The annual roots proliferate
in whatever top soil or mulch is present; the perennial roots are often deep
delving and in my experience much larger.  
Now let’s go back to the basic definition of “bulb”, because
there is a problem implied in that definition. The definition talks about a
single bud surrounded by fleshy storage tissue. But all mature bulbs contain
multiple growth buds attached to the perennial stem: these exist in various
stages of development and to the extent that they develop with their own
surrounding fleshy storage tissue they are potential bulbs. But, because they
are still intimately connected to the basal plant of the oldest bud (the one
which flowers), they are not modular. They are, so-to-speak, only potential
At this point, we might  start a discussion about whether these are
properly called bulbs or something else. Instead, let’s look at it this way:
the only time in the life of a bulbous plant when it consists of only one
growth bud and surrounding tissue is shortly after germination from seed.
Surely the time when additional growth buds are added varies, but the addition
of those additional growth buds is one of the most important, urgent things to
happen in the life of a bulbous plant. 
If you follow me here, and accept the above, then it becomes
apparent that our definition of bulb has to allow for the fact that bulbs,
except in the very earliest phases of their existence, always contain more than
one vegetative growth bud. In that sense, the bulb you hold in your hand is a
compound structure with the potential over time to develop multiple annual stems
as the perennial stem grows and expands. 
In some bulbs, such as tulips, the bulbs you dig in June are
not the bulbs you planted in September. They are new bulbs, most of the matter
of the bulb you planted in September has been used by the plant to produce a
flowering stem; most but not all. Part of it survives long enough to build the
perennial stems of the offset bulbs. The perennial stem of the tulip is the
only part which survives from year to year. 
Imagine an oak tree in winter. At the tip of each branch
there is a bud for vegetative growth, protected in the case of the oak by dry,
scaly bracts. Now imagine that all of the oak trunk and branch work disappear, all
those now detached oak buds are homologous to the bulbs of a tulip clone after
many years of growth. 
In other bulbs, the fleshy scales seem to persist from year
to year. Is the resulting mass actually a single bulb? In a sense yes, in a
sense no. Yes, because it seems to form a coherent mass – and our common sense
certainly urges this usage. But no in another important sense: the bud which
began it all has long since disappeared and been replaced by a succession of
vegetative growth buds on the perennial stem. Those old, accumulated fleshy
scales no longer surround a unique bud, they simply persist with no purpose other
than food storage. That’s one reason why we don’t consider them to be a cluster
of bulbs: the fleshy scales are there but they do not surround a unique bud for
vegetative growth.  And of course, the
whole mass still looks like a single bulb to us.
Now to the Fritillaria question which prompted this email.
When we speak of bulbs, we often make a distinction between tunicated bulbs and
non-tunicated bulbs. If you give consideration to the origin of the tunic, it
becomes apparent that the degree of tunication varies a lot among bulbs. The
tunic is what remains of the outermost fleshy scales of the bulb. This is
easily seen in the kitchen when you peel an onion, especially one where the outermost
scales layers are becoming soft and mushy. In nature, these would dry into the
papery layer we call onion skin.  Tulips
have a heavy tunic, daffodils have a flimsy one. Bulbs which mature under damp
conditions are apt to have thin or defective tunics. Bulbs which mature under
dry conditions are more apt to have discrete undamaged tunics. 
Fritillaries are usually placed among the non-tunicated
bulbs. However, if you examine newly matured bulbs of Fritillaria imperialis
and F.  persica, you will usually be able
to find patches of tissue thin tunic material. This is more easily seen in F.
persica than in F. imperialis, but both species show this.
In the culinary onion, you can see that the onion skin is
formed when the outermost layers of the onion dry out. Those layers are the
scales of the onion bulb. If the sparse tunic material seen on Fritillaria
imeprialis and F. persica  is formed the
same way, then that indicates to me that bulb scales have dried out to form it.
 So , I’m in the camp which doubts that
the scales seen in purchased bulbs continue to grow year after year to form
larger and larger scales. 
However, there are instances of bulbs which do retain large
scales indefinitely. In some lilies, such as Lilium superbum, the bulbs produce
networks of rhizomes with the newest bulbs at the periphery. The oldest bulbs
remain connected to the network, but as far as I know do not sprout again (but
they can be broken up and the scales will form new plants).  Nor do they increase in size. 
So, if those big frits are keeping big scales from year to
year, they are not the only liliaceous plants to do so. 
Here’s a challenge for the group: get some nice new bulbs of
the big frits and then either stick sterilized pins into the fleshy scales or stain
the scales in some way. At digging time the next year, see where the pins or
colored scale matter  end up: are they
still firmly inserted in a scale or part of a healthy bulb, or are they loose
in the soil outside the mass of the bulb? 
That should answer this question about the persistence of big scales in
these bulbs.  

Jim McKenney

On Friday, June 6, 2014 7:24 PM, Jane McGary <> wrote:

Ian Young certainly knows more about bulbs than I do, but if I happen 
to lift one of my fritillarias while it is in growth, there is a bulb 
of the usual size present. Laurence Hill's photos of entire 
fritillaria plants, in flower, also show the bulbs. I wonder if this 
characteristic varies among the different subgenera? For instance, 
subgenus Liliorrhiza (the western American species) may add new 
scales attached loosely to the basal plate (e.g., Fritillaria biflora 
and F. striata) or may maintain a slowly enlarging disc-shaped bulb 
with numerous loosely attached "rice grain" offsets (the F. affinis 
group). In both cases the bulb is present at any time in the growth 
cycle. In some other subgenera, I think the bulb may diminish in size 
during flowering, but it doesn't disappear. Nor do fritillarias 
produce "dropper" bulbs at the base of the stem as tulips do, 
although some of the American species such as F. striata will "drop" 
their hooked scales down early in the plant's life.

Perhaps the disconnect between our observations has to do with the 
distinction between "layers" (as on a Narcissus or Allium) and 
"scales," as on a Fritillaria or Lilium? It is true that Fritillaria 
bulbs do not have completely enveloping layers like an onion or many 
of the amaryllids.

I can't defend my position with photos at the moment since all the 
frits are dormant or nearly so, but I can measure some bulbs this 
summer and, if I have enough of the species, I'm willing to lift them 
in flower and see how different the bulb size is, if at all.

Jane McGary
Portland, Oregon, USA

>I quote (Ian Young):
>"Classic bulbs such as Narcissus are perennial adding extra layers 
>each year all fritillaria bulbs are annuals, replacing themselves 
>completely each year with a new one that forms at the base of the 
>growing stem."

pbs mailing list

More information about the pbs mailing list