Ranunculaceae 

In this series, I aim to give you a quick introduction to some of the common plant families found in the UK. Learning to identify plant families is a great help in identifying individual plant species you come across - if you know the family, then you know where to start looking for the species in a guide, and identifying the family is an achievement in itself. Plants are classified into families based on characteristics that they share; this is then narrowed down further into genera and then into species. So, the way to identify a plant’s family is to know these characteristic features.
Today's family is the Ranunculaceae or buttercup family. This family contains over 2000 species. Although members of the Ranunculaceae are found worldwide, they are most diverse in temperate and northern parts of the world. Most are herbaceous annuals and perennials, though there are also some climbers and shrubs.
Quite a few popular ornamental plants are in the Ranunculaceae family, for instance Clematis, hellebore (Helleborus orientalis), columbine (Aquilegia vulgaris), globe flower (Trollius europaeus) and pheasant's-eye (Adonis annua). Many species contain toxic compounds, like the poisonous ornamental wolfsbane (Aconitum napellus). Some species, like meadow-rue (Thalictrum) and Goldenseal (Hydrastis canadensis), are used in traditional medicine.The seeds of black caraway (Nigella sativa) are used as a spice. Wild plants in the Ranunculaceae found in the UK include creeping buttercup (Ranunculus repens), meadow buttercup (Ranunculus acris), lesser celandine (Ficaria verna), wood anemone (Anemone nemorosa), marsh marigold (Caltha palustris) and traveller's joy (Clematis vitalba). The majority of the species in the UK are herbaceous perennials or annuals, and some are aquatic plants.
The flowers of Ranunculaceae are most commonly actinomorphic, so, symmetrical in more than one plane, though some species are zygomorphic, which means they are only symmetrical in one plane. They are pollinated by insects.
There are usually five petals and five sepals, though this varies with species, and in some the petals and sepals look similar. Petals are often yellow and are also often quite glossy. Clematis actually have no petals, but the sepals are coloured and large, like petals. The flowers have many stamens and usually many carpels - the female part of the flower consisting of the ovary, style and stigma. These carpels generally have superior ovaries, meaning they are attached above the rest of the floral parts and the carpels stay separate from one another.
The carpels form lots of separate fruits in one flower. These fruits are either achenes, dry fruits that don't split, or follicles, dry fruits which split open when ripe. These fruits and seeds are dispersed in a number of ways. The achenes of buttercups hook onto clothes and animal fur, while Clematis have structures that catch the wind.
The leaves of Ranunculaceae are arranged alternately on the stem (excepting Clematis, which has opposite leaves, just to be different). The leaves are commonly lobed or divided.
So, a plant with many stamens, many separate carpels with dry fruits and lobed or divided leaves is likely in the Ranunculaceae.
Three species to look out for are:
- Lesser celandine (Ficaria verna)
- Marsh marigold (Caltha palustris)
- Creeping buttercup (Ranunculus repens)
[Note, botanical names should always be written in italics (or underlined if handwritten)]