Canna by Mail Order

Taxonomy is the science of classifying and naming things.

Living things are classified according to the system developed by Carl Linneus in the 16th century. His system is based on presumed evolutionary relationship.

His broadest classification is Kingdom, and so we have the Plant Kingdom, the Animal Kingdom, etc. (there are others, such as fungi, bacteria, viruses etc). Below Kingdom, there are a number of other broad classifications such as Class, Order, Family, Genus and Species. The species is the finest level of classification normally used to define naturally ocurring individual types of living thing.

Lineaus also introduced the system where each type of naturally occurring living thing is given a name in 2 parts. So we have, for example, Canna indica. The first part Canna, refers to the genus, and the second part indica refers to the species.

Maybe I should mention something about which botanists are quite picky, and where non-experts can and often do make mistakes. Note that the genus always begins with a capital letter, and the species always begins with a lower case letter. So, writing Canna indica is correct. Writing Canna Indica displays your ignorance.

So, starting again, Cannas are members of the Plant Kingdom.

Next, they are flowering plants, which differentiates them, for example, from mosses, ferns, cycads, conifers, etc, which do not produce flowers.

Next, they are monocots. This is where it starts to get difficult. All flowering plants are divided into 2 groups. They are either monocots or dicots. Monocots are plants which start from the seed with a single seed leaf. Dicots start with 2 equal seed leaves. So, for example, lilies, irises, orchids, grasses, onions, bananas, gladiolus, daffodils, snowdrops, palm trees, belong to the monocots, whereas plants such as roses, cacti, apples, peas, cabbages, poppies, daisies, oak trees, waterlilies, etc belong to the dicots. As a rough generalisation, monocots have narrow leaves and leaf veins which are parallel, whereas dicots have leaves which can be all sorts of shapes, and the leaf veins are usually branched. Another difference between monocots and dicots is that monocots have flower parts in 3's or multiples of 3. Ie they have 3 or 6 petals etc. Dicots generally have flowers with 4 or 5 petals, or multiples thereof.

Next, they belong to a group of monocots known as the Zingiberales, which include just the following few plant families:

Zingiberaceae (the ginger family)
Musaceae (the banana family)
Strelizeaceae (bird of paradise flower family)
Marantaeceae (prayer plant family)
Cannaceae (canna family).

All the Zingiberales have leaves that open by unfurling, they usually have large showy leaves, and they all come from the tropics (one exception being that there is a hardy ginger, Roscoe).

So canna plants have their own plant Family within the plant Kingdom. It is unusual for a plant to have its own plant family. What is also unusual is that within the Canna family there is ony one genus, the Canna genus. This means that cannas are quite different from other plants, and are seperated from them by a wide gap in evolution. This is why cannas are so unusual, and so interesting.

Having said just above that canna is a monocot and monocots have 3 petals, it can be seen that most cannas appear to have 4 petals. This is an optical illusion. What appears to be petals in a canna flower are not petals at all. They are actually sterile stamens called staminodes. The true petals are much smaller and often not noticed, and there are 3 in number.

Within the Canna genus there are a number of species. Botanists have disagreed on how many species there should be. Historically there were very many species which may be seen listed and referred to in old and not-so-old books on horticulture. A recent (unpublished) taxonomic study by the Dutch botanist Maas reduces the total number of species to the following:

C. bangii (to 4m tall. 1400 - 2700 m alt. Peru and Bolivia)
C. flaccida (SE USA, at sea level)
C. glauca (near water, central America)
C. indica (common)
C. jaegeriana (to 5m tall, 750 - 2800 m alt. Western south America, Greater Antilles)
C. iridiflora (to 5m tall, 1800 - 2850 m alt. Peru)
C. liliflora (to 6m tall, 2500 - 2800 m alt. Bolivia)
C. paniculata (to 5m tall, 200 - 2000m alt. S Mexico, Costa Rica, and Tropical S America)
C. pedunculata (to 2.5m tall. low alt. SE Brazil).
C. tuerckheimii (to 3.5m tall. 200 to 200m alt. Andean South America, Central America to Mexico)

The japanese botanist Tanaka added to this list with 3 new species which he discovered in South America:

C. stenantha (1.5 to 2m tall. Argentina, Paraguay)
C. jacobiniflora (1.5 to 2m. Argentina)
C. amabilis (similar to C. glauca, but red flowers. Argentina)

All the rest may be taken to be variations within the species Canna indica. These include C. speciosa, C. edulis, C heliconifolia, C musifolia, Maybe at some tome we will get a formal published taxonomic stury of genus canna, which will put our taxonomy on a firm base

The strange thing about the above list of species is how few of them are found in cultivation. We only get C indica, C flaccida, C glauca, and even the latter 2 are not very common. There is one garden hybrid of C iridiflora. Recently C paniculata has appeared in seed catalogues. The rest appear lost to horitculture. Yet old pictures of C iridiflora and C liliflora show them to be gorgeous plants.