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Hybrids Of The Botanical Nature

Fancy gladiolus are products of hybridization.

Botanical nomenclature has gotten sloppy. So has breeding. Hybrids of different species are now common. Their botanical names often lack proper species designation. Instead, their names include only their genus names with their variety or cultivar names. This can seem simpler. However, it complicates the simplicity of binomial botanical nomenclature.

Interspecific hybrids involved different species of the same genus. Therefore, any genus name is the same as that of both parents. An “X” precedes its species name to indicate it as an interspecific hybrid. Its species name is as new and unique as the new hybrid. Any cultivar or variety name follows its species name in single quotes. it is all quite sensible.

Intergeneric hybrids involved different genera. Therefore, an “X” precedes a genus name of an intergeneric hybrid to designate it as such. Its entire name is as new and unique as the hybrid. Like for all botanical names, both its genus and species names are italicized. This designates them as ‘Latin’ names. Variety and cultivar names lack such italicization.

Many hybrids are naturally sterile. Most that can produce viable seed are not true to type. In other words, their progeny is very different from them, and commonly of inferior quality. Most hybrids are therefore cultivars, or cultivated varieties. They are reliant on unnatural cultivation for perpetuation. However, some naturally perpetuate vegetatively, like canna.

Tree ivy, X Fatshedera lizei, is an example of an intergeneric hybrid. The “X” in its name precedes its genus name. London plane, Platanus X acerifolia, is an interspecific hybrid. The “X” precedes its species name. Platanus X acerifolia ‘Liberty’ is a cultivar of London plane. Its species name remains, which is proper with botanical nomenclature of hybrids.

Rhododendron and rose hybrids violate nomenclature rules because of their breeding. It is too extensive for their species to be identifiable. For them, the abbreviation “spp.” may substitute for a species name. It is for “species pluralis”, which means “multiple species”. Although it is Latin, it is not italicized. Nor are their more important cultivar names after it.

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Out with the new, in with the old

Canna ‘Cannova Mango’

Canna ‘Cannova Mango’ is a relatively recent introduction to the landscapes here. I inadvertently brought it back from Southern California about two and a half years ago, without realizing that it is exactly the sort of modern cultivar that I am not at all keen on. It is new. It is improved. It blooms with a strange but trendy color. The problem is that it performs too well to not be an asset to the landscapes. Because it is so short and compact, it starts blooming early, while old fashioned Canna are still only foliar. Because it replaces older stalks with newer stalks so efficiently, it is rarely without bloom until frost. Other cultivars of the series bloom yellow, lemon (which is implied to be distinct from yellow), orange shades (?), red golden flame (?!), rose, scarlet with bronze foliage or orange with bronze foliage. The tallest are less than five feet tall. Regardless of my disdain for modern cultivars, I do not doubt that all of them perform as impressively as ‘Cannova Mango’. Nonetheless, I prefer the older and formerly common sort. A relatively compact cultivar that stays less than about four feet tall with simple green foliage and billowy but simple red bloom has been relocated through a few landscapes here since the early 1980s. Although not many rhizomes survive, I intend to grow more of it, even if not so much within the landscapes at work. Its bloom begins a bit later, and is neither as profuse nor as continuous as that of ‘Cannova Mango’, but it has history here. Besides, its more relaxed foliar texture and bloom somehow seem to be more compatible with the surrounding forested setting than the almost too refined modern cultivars, with their perfectly compact form, overly profuse bloom, and strangely modern floral color.

Unidentified old fashioned red Canna with green foliage.

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Cultivar Is A Cultivated Variety

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Most cultivars need to be cloned.

A plant ‘variety’ is a group within a species that exhibits distinguishing characteristics. A ‘cultivar’ is simply a cultivated variety. The first five letters of ‘cultivated’ merged with the first three letters of ‘variety’ to form the word ‘cultivar’. A variety should be self perpetuating to some degree, and may be naturally occurring. A cultivar perpetuates by unnatural means, and would go extinct otherwise.

Of course, the distinction between variety and cultivar is not always so obvious. Varieties of nasturtium were selected from plants that displayed desirable qualities. Seed of these varieties grows into plants that display the same qualities. However, without continued selection, some varieties eventually revert to a more feral state in only a few generation. They are not truly self perpetuating.

Most hybrid tomatoes are unable to perpetuate themselves naturally. Their seed is either not viable, or is very genetically variable. Genetically variable seed grows into plants that are very unlikely to produce fruit that is comparable to that which produced their own seed. Nonetheless, hybrid tomatoes grown from original (primary generation) seed are generally varieties rather than cultivars.

The distinction might be that they grow from seed. A plant that is cloned rather than grown from seed is a cultivar. Cloned plants can be grown from cutting, layering or grafting onto understock, but are genetically identical to the original. Some rare camellias grown now are genetically identical copies of original cultivars that were developed centuries ago. Their seed would not be the same.

Some cultivars developed from selective breeding. Others were random but appealingly distinctive plants in the wild or even in landscapes. Many originated as ‘sports’, which are mutant growths of otherwise normal plants. For example, some plants, on rare occasion, produce stems with variegated foliage. Cuttings taken from such variegated stems became popular variegated cultivars.

Seed from a variegated cultivar is very unlikely to produce more variegated plants.