Ranunculaceae - Fact, Fiction and a bit of Botany
There are 58 genera in the Ranunculaceae family and about 1,750 species, The type genus Ranunculus has 250 species of which over half are Eurasian in occurrence. So we have plenty to interest us.
How does our favourite family fit into the botanical scheme of things? There are about 300 families of dicots, and about 80 families of monocots. It is generally assumed that a plant family contains truly related genera, yet when it comes to putting families into sub-classes and orders, then opinions outweigh the facts. Indeed the relationships between families are frequently based on tenuous data at best.
Some botanists put the ranuncs (a fairly well-integrated natural group) in possession of older, less complex, less elaborate characteristics, and place their gene-stock closer to the origins of flowering plants. Although ranuncs are almost all non-woody herbaceous plants, they may have evolved from ancient primitive woody ancestors. In fact, magnolias could well be thought of as giant woody buttercups of old. Ranunculaceae, although true dicots, often have seeds with one cotyledon (seed leaf) far more developed than the other; almost a memory of, and possibly a descent from, ancient pre-monocot ancestors?
So what does make a ranunc?
- FLOWER STRUCTURE is basically simplistic, usually (but not always) with many carpels, many stamens, and free (that is, not joined to each other). A very typical feature, considered ancient and primitive, is that floral parts are arranged spirally, not in rings as in most flowers, and on an elongated receptacle or central core.
- CHEMICALLY very many ranuncs are toxic to animals. Nasty alkaline poisons such as aporphines, and benzyl isoquinolines, abound. One supposes that naming a cow Buttercup referred to the butterfat content in her milk. However, had she grazed on buttercups, even the best of vets might not have been able to save her.
- ANATOMICALLY leaves are alternate, sometimes nicely adapted and simplified when aquatic, like water crowfoots etc. Rarely are there any woody or semi-woody tissues, so apart from Xanthorhiza and Clematis all are herbaceous. Xanthorhiza is an unusual genus from North America, with only one species. Have any of our members grown it?
Consolida and Delphinium seeds have been used as an insecticide; how green can one get? Aconitum occurs as four species in Europe, and is cultivated as a drug source. Records show that aconite was administered to criminals in the distant past, but whether as a medicine or as a non-expensive means of capital punishment such records are unsure. Definitely not to be tried at home. Helleborus has a dedicated following, and of the 11 European species most have been much hybridized. If hellebores flowered in mid-summer, they could lose some of their popularity, due to the wealth of colourful floral competition at that time of year. Also, like many others they can show high toxicity. Hellebore seeds are unique among ranuncs in that they possess an eliasome (oil body), which is alleged to attract both ants and snails. The former are said to carry the seeds away as a food source and thus act as a distribution mechanism; the latter, however, are sadly unaffected by the considerable toxicity of the self-same seeds. No snail nor slug killer potential here. As for rarity, the one special note has to go to Ranunculus ophioglossifolius. If a 17-letter specific name wasnt enough (and incidentally it means leaves like an adders tongue) this rare and insignificant annual happens to be the subject of the worlds smallest nature reserve, at Badgeworth in Gloucestershire. Have any of our members visited there, and seen it?
I can only summarise my comments by saying that there is a great deal more to our much-loved Ranunculaceae than we may think.
First published in the Ranunculaceae Group Newsletter, Autumn 2008
and subsequently in Cornucopia Issue 25.
© Copyright for this article: Bob Foulds
This article was taken from a copy of Cornucopia that was published in 2010. You could be reading these articles as they are published to a national audience, by subscribing to Cornucopia.