Botanical Names Explained It's a complex world out there and the botanists don't seem to make it any easier! And there is nothing more confusing than listening to a bunch of gardeners talk in streams of apparently meaningless gobbledy-gook. Who do they think they are?
But hold on a minute, don't put it down to garden snobbery. Botanical names give us clues about plants, their relatives, their cultural needs and they are well worth learning.
Botanical, Latin or Scientific Names? All plants have a unique name and this is often called the scientific name, botanical or the 'Latin name' as many are based on Latin. Many botanical names are derived from Greek, a persons name (the discoverer, sponsor or someone-else altogether!), are descriptive or give the place of origin of the plant. For this reason we prefer to use the term 'botanical name' rather than 'Latin name'.
The system we use today is based on that developed by Linneaus, a Swedish naturalist, developed in the 18th century. Botanical names all have two main parts: a generic or family name and a specific or species name. Thus, the human world we have the Brown family, and we have John, Jane and Mary Brown within that. In the plant world we have the celmisia family, Celmisia, and its member Celmisia semicordata, Celmisia spectabilis, etc.
Plants have names, just like people
The difference between the human naming convention and that of plants is that each pant generic or family name occurs only once. Specific names may occur a number of times (e.g. reptans or alba) but, coupled with the generic name, each plant has a unique name. Think of all the New Zealand plants that are Something haastii or Something chathamica!
Why Not Common Names? Many gardeners and most plant nurseries prefer botanical names as they avoid the confusion that common names can cause. Common names can be very local, some plants don't have a common name, and others have more than one.
More than one plant has the same common name; in the UK an 'Ash' is actually a Fraxinus while in the USA it is really a Sorbus; 'Arums' are frequently not Arums at all Zantedischia; and an Aconite can be the late summer flowering, deep blue flowered perennial Aconitum or the tiny winter flowering bulb Eranthis hyemalis.
And then there are the plants that have more than one common name; the climbing pest Clematis vitalba is known as Old Man's Beard and Traveller's Joy; Bergamont and Bee's Balm are both Monarda didyma; and Erythronium as Trout Lilies and Dogs Tooth Violets.
Trout Lily, Dogs Tooth Violet or Erythronium?
Parts of Botanical Names The way the name is built up is based on Latin grammar rules. Each plant family name (eg. 'Cordyline') is a noun and has a gender (i.e. is male or female). Species within each family are adjectives ('australis', 'indivisa', etc.).
Botanical names are usually written in italics as in Cordyline indivisa.
Sometimes, perhaps too often for gardeners' liking, the scientists will change a botanical name and thus we get Brachyglottis monroi (syn. Senecio monroi) where the name in brackets is the previous or, occasionally, less well-known name. This is also known as the 'synonym'.
The great value in understanding the botanical name comes from following the family trees through and using the other, descriptive clues in the name. Celmisia spectabilis is a very showy or spectacular celmisia, Coprosma prostrata and Cotoneaster horizontalis are, well, prostrate growers, and Cercis chinensis comes from China and Cercis canadensis from Canada; Geum montanum comes from the mountains; Prunus autumnalis flowers in the autumn.
Great Value in Understanding Botanical Names
The Structure of Plant Families
Plant Orders A step up from the botanical name we have plant orders. These are larger families of plants.
A plant order is a family of different genera that are sufficiently similar, e.g. Magnoliaceae or Ranunculaceae are plant orders that contain many different genera that share a key characteristic(s).
The plant order is not included in the botanical name, except in scientific situations or in gardening textbooks and plant dictionaries where it gives us clues that clematis, ranunculus and hellebores, all members of Ranunculaceae, have something in common.
Genera The genera or genus a plant family such as the New Zealand family of pohutukawa and rata trees is Metrosideros, and within this genus we find Metrosideros excelsa, Metrosideros umbellata, Metrosideros robusta, etc
Species A species is those plants that are the same and produce viable offspring. Plants within a species can vary in small ways, such as differences leaf colouration resulting from environment, climate and soil. And, so, within species you can have subspecies, varieties, cultivars and hybrids.
Variety Differences in climate, soils, and aspect can cause these differences to be sufficiently distinct that botanists will distinguish between different varieties (often shown as 'var.') within a species. Clianthus puniceus var. maximus differs from the so-called 'typical' form Clianthus puniceus.
Subspecies When there is no overlap in the geographical distribution of the plants, the variety may be called a subspecies (often shown as 'ssp.', as in Crocus biflorus ssp. crewei). These are still able to produce offspring when two subspecies within the same plant species are brought together.
Cultivars Sometimes gardeners may select a particular plant because of leaf colour form or flower. This selection is still genetically identical to these within the species and must be propagated vegetatively (cuttings, division etc) to continue the desired attribute, as seed grown progeny may not 'come true', that is, they may not carry the particular attribute sought.
These plants are called cultivars and the cultivar name is shown in inverted commas, e.g. Astelia chathamica 'Silver Spear'
Hybrids Where different species within a family or different families produce offspring, the new plants are called hybrids. Hellebores are very promiscuous in this way. Apart from physically separating parent plants or hand pollinating it is all too easy to end up with hybrids rather than the species plants you may covet.
These plants are shown as a 'cross' such as Corokia x virgata 'Bronze King', where virgata is not a species but a hybrid between two of the Hamamelis species. Camellia x williamsii 'Donation' is a hybrid where Camellia williamsii is known to be a parent. Hybrids can also be 'intersectional hybrids', that is, they occur between different genera as in x Cupressocyparis, a cross between Chamaecyparis and Cupressus.
So while sometimes it does seem as if it is 'It's all Greek to me!', it really is worth finding out the botanical name.
Using the botanical rather than a common name is not garden snobbery. It is simple good sense, and it saves the confusion common names can cause, unless it is as unpronounceable as Paeonia mlokosewitschii, named for Frederich Mlokosewitch who found it, but known almost universally as 'Molly the Witch'.