The Basic Botany of Bulbs
We tend to think of vegetables as things to eat.
For this reason I prefer the classification Plant
Kingdom, as is used in Great
Britain, rather than Vegetable Kingdom. But
where in the order of things do plants fit? The
Roman writer Pliny devised a classification, not
scientifically accepted today, that I am sure is
used by gardeners the world over, the majority of
them knowing nothing about Pliny, and possibly
caring even less! Pliny's criteria are size and
form, and he divides the plant kingdom into
trees, shrubs and herbs -a very sensible arrange
ment. In the Middle Ages another classification,
also quite sensible, divided plants into medicinal,
edible and poisonous varieties. However, this
tells us nothing about the actual plant; a tree, for
example, can be considered all three. Still, this
was, when combined with the earlier classifica
tion, a useful tool. We could have a medicinal
tree, an edible herb and a poisonous shrub. Man
was getting there.
Looking closely at plants, the great Swedish
botanist Carolus Linnaeus devised a classification based
on the number of stamens in the flowers of plants.
Although this classification was discarded, Linnaeus
introduced a system of naming plants still used today.
The scientific, or botanical, name of a plant is the same
the world over, and each plant has only one correct
name. Our Easter lily is Lilium longiflorum to someone
from China, England or France. Locally used common
names vary widely, but scientific names are recognized
by all. Linnaeus devised the scientific, two-name
method of identification, the genus (plural, genera)
being the first, followed by the species name, the
The plant kingdom is divided into two
subkingdoms: Thallophyta (plants that do not form
embryos), such as bacteria, slime molds, various algae
and true fungi, and Embryophyta (plants that form
embryos), the subkingdom into which bulbs fall.
Embryophyta is broken into Bryophyta (mosses and
liverworts), obviously not bulbs-and Tracheophyta,
plants with vascular systems. Tracheophyta includes the subphyllum Pteropsida,
which is divided into three classes: Angiospermae, the
true flowering plants; Filicineae, the ferns; and
Gymnospermae, the conebearing plants and their
relatives, such as the conifers.
With bulbs as our topic, we are concerned with
only one of these classes, the Angiospermae. But there
are many flowering plants, and this class is divided into
two subclasses: Dicotyledoneae and
Monocotyledoneae. In everyday speech these plants are
referred to as "monocots" and "dicots." Monocots
produce one leaflike structure after the seed
germinates; dicots, two.
After germination, as plants develop, they
produce true leaves. Monocots have leaves that are
generally alternate, with parallel veins and simple
form. The flowers are constructed of four alternating
whorls of parts-sepals, petals, stamens and carpels-with
each part being trimerous (in threes or multiples of
three). This is worth knowing, as it helps in the
identification of flowers.
Dicots have leaves veined in a netlike pattern,
and usually the leaves are narrow at the base and have
a petiole. In dicots the parts of the flowers are usually
in multiples of five and are called pentamerous
(5-merous), or in fours and called tetramerous
(4-merous), and they have a distinct calyx and corolla.
(Some of these terms might be foreign to the reader.
Turn to page 6 for a discussion of flower parts and
These classes and subclasses are again
divided into orders, each order containing one or
more families. If this sounds complicated, don't
worry; now we are getting to the more relevant
information on the orderly classification of our
It is perhaps easier to understand what comprises an
order if we examine one in particular. Lilies are my
favorite flowers, so let's look at the order in which
these lovely plants belong, together with the iris and
the amaryllis. Similarities join these families -Liliaceae,
Iridaceae and Amaryllidaceae-in the broadest way. This
trio of families make up the order Liliales.
All these families have flowers made up of three
petals and three sepals; ovaries that are in three parts;
and six stamens in two rows of three each (Iridaceae
have one row of three). It is certain an iris is different
from a lily, yet if you picture the single flower of a
gladiolus, a lily or an amaryllis, you can begin to
appreciate that they have quite a lot in common.
The ovary is located in the center of the flower. The
petals and sepals are attached to the flower below the
ovary in the case of the lilies; because the ovary is
above that attachment point, it is called "superior."
Tulips and lilies are in Liliaceae. In Amaryllidaceae the
flowers have the same parts as they do in Liliaceae, but
the ovary is located below the point where the petals
and sepals are attached, and thus it has an "inferior"
ovary. The amaryllis and the daffodil have inferior
ovaries, and are classified in Amaryllidaceae.
When we take a look at the iris, gladiolus and
crocus, we find that, like the plants in Amaryllidaceae,
the flowers have inferior ovaries but only three
stamens. There is another significant difference in these
members of the Iridaceae; the outside petals are broad
and recurved (they curl back), and the inner ones are
narrow and erect. At first glance there are many
similarities among these three families (remember, they
are classified in the same order: Liliales). Upon closer
examination, however, differences are evident, and so
they merit being classified into three different families.
The juxtaposition of petals and sepals, the number
and placement of several parts of the flowers, is similar,
yet the differences are sufficient to merit three different
families. It's rather exciting to realize that if you do not
know the name of a flower but note that it has three
sepals, three petals, an inferior ovary and three
stamens, you know it belongs to Iridaceae. You can
then check the genera (singular form: genus) in this
family, and so arrive at the identification of the plant.
But we have now introduced another word, genera.
Every family has one or more genera. All daffodils and
narcissus, for example, belong to the genus Narcissus.
The flowers of plants that are structurally the same are
classified in the same genus. While the tulip seems, in
number and placement of flower parts, the same as the
true lily, there is an obvious difference, one that can be
seen just by looking at the plants; apart from the
flowers, the foliage is different. The tulip has no foliage
on the stem, but the lily does. The lily has several
flowers on each stem, but the tulip seldom more than
one, and the form of the flower head is different. Thus,
while related (both in the order Liliales and in the
family Liliacea), the tulip and the lily are different. The
tulip is placed in the genus Tulipa, and the lily, in
Lilium. Now we have an understanding of the meaning
of the word genus. This brings us to the next step of
There is a difference between an Easter lily and a tiger
lily. The plants are classified in different
species. The Easter lily is Lilium longiflorum, the tiger lily
is Lilium lancifolium. How is the species name determined?
It can describe the flower"grandiflorum" means "large
flower," "rubrum" means "red," "album" means "white."
It can honor the person who discovered it, as in the
case of Lilium davidii, named after Armand David, who
discovered it in western China in 1904. A specific name
can provide information about the geographical area
where the plant grows, as in the case of Lilium canadence,
a lily that grows wild in eastern Canada. Frequently a
plant of one species may look very much like another
classified in the same species, but yet is not exactly the
same. A slight but consistent difference is enough to
warrant separating two very similar plants, though they
share the same species. Flowers may be fewer but
larger, leaves wider, the plant a little shorter. Such
differences are not sufficient to merit the variant being
given full species rank, but the difference has to be
acknowledged. In such cases the plant in question is
described by the original species name, and is given a
"subspecies" name after that.
A good example is the case of Lilium canadense. It was
noted that the form growing east of the Appalachian
Mountain Range has broader leaves that are not as
tapered as others. For this reason, these plants are
known as Lilium canadense subsp. editorum. The word
"subsp."-short for subspecies-is not italicized, the other
names-genus, species and subspecies-are.
Elegant, free flowering, and full of grace, Lilium canadense is a
must if you have a woodland setting, where it should be left
undisturbed for years.
While such a physical difference is given subspecific
rank, it would not always be merited just by flower
color. The natural reproduction of the species in the
wild, by means of seed, can produce
seedlings of a different color. If this color (color is used
as an example-height and foliage form
might ht be other examples) is consistently found
might consistently the same, then that variant is
known as a variety of the species. If the usual color of
the flowers of one species was red, but consistently a
white-flowered plant was found, then the words "var.,"
album" would be added to the name. The album would
be in italics, but not "var.," which is the accepted
shortening of the word variety.
Many people refer to a plant as a "variety" of this or
that. `Peace' is called a "variety" of rose, `Big Boy', a
"variety" of tomato. But in both these cases the variety
has been man made, and these plants are the result of
hybridization. Obviously the same is true of the "varieties" of tulips, gladiolus,
dahlias and many other popular bulbs. These are
correctly known as cultivars, meaning they were
created by humans.
The correct way of writing a cultivar name is
within single quotes; it is not italicized. Thus, we have
Tulipa 'Clara Butt' and Lilium `Enchantment'. The
cultivar name is selected by the producer of the new
plant, and once registered, the name cannot be used for
another introduction in the same genus; it can be used
in a different genus. Thus you may well find `Peace'
used for a rose, a lily and a gladiolus as they are all
Cloned and Strains
In the case of the lily `Enchantment', all existing
`Enchantment' lilies were derived from a single,
original bulb by vegetative propagation. This means
part(s) of the original bulb were removed and grown
on. The resulting plant is known as a clone. Purchase a
`Red Emperor' tulip and you expect a tulip identical to
that you purchased under that name in previous years.
`Golden Delicious' apples are the same everywhere,
because they are all clones.
Sometimes plants-certain lilies, for example-are
sold as "strain." `Golden Splendor Strain' is a lily
strain. Often when a strain becomes well established,
the word "strain" is dropped, so you might see the
bulbs sold as `Golden Splendor'. A little variation may
be found among plants of the same strain, but the
differences will be slight and all would be recognizable
as `Golden Splendor'.
Strains are raised from seed. Selected parent
clones are crossed, and the offspring are the strain. As
years go by, strains are often improved. Hybridizers
constantly upgrade the quality. Deeper color, stronger
stems, increased size and number of flowers-such
improvements are made by changing the parent clones used to produce
the seed from which 'Golden Splendor' plants, for
example, are raised. The cost of introducing a new
strain into the market is high. Once a strain has been
established and has earned a reputation, it pays the
grower to continue to market the strain. Over time
that strain may be improved in a dramatic way, yet
because of name recognition, the name is continued. It
is not critical for the home gardener to know whether
a plant is a strain or a clone. It is essential for the
nurseryman, who might be forcing the bulbs, to know.
Why? Clones, identical in every way, will respond in a
given way when forced. A strain, made up of
individuals, will show variations, perhaps some coming
into bloom earlier, or later, or being shorter or taller.
Such variations, even slight ones, cause problems when
schedules are prepared; greenhouse space is valuable,
and such variations can be quite costly.
You will find reference to hybrids in many books
and catalogs. We are all hybrids ourselves! We are the
result of the crossing of our fathers and our mothers.
So it is with plants. New plants derived by crossing
two plants are hybrids. When species from two genera
are crossed, which happens rarely, we call the result an
intergeneric hybrid. One such intergeneric hybrid in
the world of bulbs is X Crinodonna. This was a result of
crossing a Crinum with Amaryllis, belladonna. The hybrid
has a bit of both parents' names, and is preceded by a
Horticultural classifications are needed for a number of
purposes. They allow accurate comparison and
competition with other plants of the same ilk. You
have probably noticed that some dahlias have flowers
the size of dinner plates. These large flowers are called
flowers are single, others still are shaped in little balls,
or are small, medium or large, or ruffled. We classify
these differences in order to describe the plants
accurately. Obviously to be correct in competition and
in our gardens, we want to be able to select the exact
type of flowers we want. Knowing that this cultivar (or
strain) is of a certain class enables us to obtain exactly
what we want. Similar types are classified together.
While visiting a breeder of Alstroemeria, wonderful plants
that are great cut flowers, I came across this specimen,
which has good color and great vigor.
Not all genera have been refined to this degree,
just the larger ones with many different types and
forms. Daffodils (the Narcissus), tulips, lilies, dahlias,
crocus, gladiolus and iris have horticultural
classifications. These classifications are compiled by
students of the various genera. They are logical and,
unlike scientific classifications, horticultural classes are
based on criteria plainly
visible to the naked eye; understanding them doesn't
require great botanical knowledge. Is it really necessary
to know much about genera, species, families,
subspecies and clones in order to garden? Of course
not. If a gardener is going to have a measure of success
with plants, he or she must have a love of beauty and
of plants themselves. A gardener must be orderly,
thoughtful, observant and imaginative. A gardener must have
the ability to look into the future and picture the
garden that is being created. A given garden may lack
form and color, but invariably one finds a plant
growing there to perfection, and this excuses many a
fault. But achieving a good garden, having plants
complement each other in an attractive border, where
each plant is in just the right place, does require
knowledge. Knowing the relationship of one plant to
another, knowing the names, where they come from
and the conditions they enjoy in the wild, may not be
essential to creating a garden. But it certainly is not a
disadvantage to have such knowledge, and the more
you know about plants in general, and individual
plants in particular, the more enjoyment you will have
from gardening. The scientific aspect of horticulture is
directed as much toward the improvement of the
gardener as of the garden itself. Perhaps one is the
reflection of the other. Try to learn and understand as
much as you can, but don't worry too much over it.
The plants know how to grow -we do not need to teach them!
Listed in catalogs but not as popular as it should be, Fritillaria persica is an
easy-to-grow species with flowers and foliage that form a pleasing
There is an obvious need to describe the form and
shape of flowers, their colors, petals and sepals. It
is a good idea to be acquainted with the various parts of
a flower, and their functions, too. When a description
is given in a catalog, you want to be able to envision
the flower, and then plan for the best location for the
plant, and place complementary plants around it.
A flower is made up of several parts. Those
essential for reproduction are: the stamens, the male
part of the flower that produces pollen; and the carpet,
the female part that in the majority of cases is made up
of the stigma, style and ovary. The seed is produced in
the ovary, and it is the purpose of the flower to
produce seed so the plants can reproduce themselves in
seasons to come.
Iris ochroleuca is a lovely species that remains in flower for a long
time, a quality passed to its offspring the Spuria Iris (the other
parent being Iris spuria). Bold plantings add much interest to a
Essentially, it is the perianth segments that one
commonly thinks of as a flower, and generally there
are outer and inner segments. The outer whorl of
segments is called the calyx, a collective name for the
sepals. These protect the inner parts and though they
can be green, in most bulbous plants they are another
color. When joined together they form a tube, as is the
case with crocus flowers. Inside the sepals are found the
petals, generally brightly colored, and though the sepals
and petals may be of the same color, they are not
always so. The collective name for the petals is the
corolla, and when the petals join to form a tube, as in
the daffodil, it is from the end of the tube that the
corona extends. It is this corona that forms the mouth
of the trumpet in many of the large-trumpet daffodils,
and it is an extension of the tube.
Often a trumpet is formed by the sepals and
the petals, without it being possible to tell one from
the other. This type of trumpet is said to be made up of
tepals; trumpet lilies are a good example. It is also
impossible to differentiate between sepals and petals in
the case of tulips, and for this reason a tulip flower is
said to be made up of tepals.
Inside the perianth segments are found the
stamens. At the top of the stamens are the anthers,
which carry the pollen grains. Usually (but not always)
yellow, the grains are the equivalent of human sperm.
Anthers are supported by filaments or stalks, and
sometimes these emerge from the perianth tube, as can
be seen if you cut open a daffodil flower. In those
families regarded as relatively primitive, such as
Ranunculaceae, there are many stamens; in the
advanced families, such as Liliaceae, there are fewer.
Stamens are placed so that there is a good chance of
pollination occuring, the transfer of the male gametes (pollen)
to the female part of the flower so that seed can
The ovary is found in the center of the flower.
Above the ovary is a slender tube, the style,
terminating in a structure called the stigma. The stigma
catches the pollen in various ways. Pollen carried by
wind can be caught by a
branched stigma or one with feathery appendages.
Some stigmas exude a sticky substance that traps the
pollen traveling on the hairy legs and bodies of such
insects as bees.
The pollen grain germinates on the stigma and
forms a tube down through the style. The male gamete
travels down the tube, and when the tube comes into
contact with the female gamete, the male and female
unite, and a seed is formed. This may be a simplistic
way to describe what takes place, but it is not
inaccurate. Many regard the fluid excreted from the
stigma as food for the germinating pollen grain(s), as
well as being a substance to trap the pollen.
The purpose of the color and fragrance of flowers
is to attract insects. At the base of the petals there may
be glands that excrete a sweet substance that is also
attractive to them. This substance is nectar, made into
honey by bees. It is from these nectaries that scents of
flowers are also excreted. Some nectaries are visible to
the naked eye, as is the case with lilies, others are
visible only with magnification.
These remarks offer insight into the purpose and
composition of a flower. There are many adaptations,
and the illustrations on pages 8-9 will help in
understanding the physiology of various bulbous
FORMS OF FLOWERS
On Arranging Lilies
Often when lilies are used in an arrangement,
the stamens will be cut off and discarded. This
is to prevent the pollen from staining the
clothes of the arranger or of someone
admiring the flowers. To me this decreases the
attractiveness of the flowers, but it is
understandable. The stigmas of lilies often
produce so much fluid that it drips, and as it is
extremely sticky, this can be a disadvantage.
Precautions taken to avoid problems include
clipping off the stigma. Again, in my opinion,
this disfigures the flower.
If pollen happens to stain a garment,
allow it to dry, then simply brush it off. If
stigmatic fluid drips onto furniture, a little
warm water on a clean cloth will remove it
easily. If pollen stains petals, it can be
removed easily with a ball of cotton dipped
Not all bulbs produce flowers with recognizable petals
and sepals. An example is Haemanthus, where the color
is due to many perianth segments that form a tube
from which stamens protrude; there are six stamens per
"flower," and many flowers in a flower head. Thus the
common name of paint brush is often given to these
flowers. Another example is the calla lily, where the
female and male flowers are arranged on a spadix that
looks like a long cylinder inside the colorful spathe,
and which surrounds the cylindrical column of flowers.
Technically this spadix is a fleshy
axis on which the sessile (stalkless) male and
female flowers are arranged. This arrangement is
typical of the family Araceae, the Arum family, and
it is the spathe that is colored and attractive. In the
case of these flowers, the fleshy axis secretes a
sticky substance that attracts insects and thus
The composition of flowers is a fascinating
subject. They are complex and deserving of greater
discussion, but that is not the purpose of this book. I
do feel that the information in this chapter is basic
knowledge essential for all gardeners worthy of the
name to understand. Flowers are indeed
wonderfully made. It is hoped that the reader will
take a minute or two to enjoy exploring the
composition and texture of flowers.
New hybrids are the result of years of work by hybridizers. We thank Klehm Nursery for this lovely Siberian iris
`Heliotrope Bouquet'. (Photo courtesy of Roy Mehra)