UNITED STATES —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.
Botanical nomenclature should be this simple.
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.
Highlight: Pacific Coast Hybrid Iris
Several species of iris are native to the West Coast of North America. Iris douglasiana is probably the most colorful species. Hybridization with the others improved its floral color range and other characteristics. Several of such hybrid cultivars collectively became the Pacific Coast hybrid iris. However, the various cultivars developed from various ancestry.
Most Pacific Coast hybrid iris are finishing their bloom about now. Some bloomed earlier, at the end of last winter. Their flowers can be various shades of blue, purple, red, orange, yellow or white. This includes lavender, burgundy, rust, rose, coral, gold or creamy white. Only green colors lack. Brown pods of sterile seed are visually unappealing after bloom.
Flowers are about three or four inches wide and stand about a foot tall. Individual flowers do not last long, but bloom in succession for quite a while. Grassy and dark green foliage develops low mounds that stay lower than bloom. Propagation is simple by division from large foliar mounds during autumn. Generous watering can cause rot and patchy growth.
