Creeping Buttercup - A Short Study - Part 1

Buttercups bring such a splash of colour to grasslands and meadows in the summer that everyone seems to know instinctively what they are. This is probably helped by the old childhood game of testing if your friends like butter by seeing if the buttercup shines under their chin (more on that in part two).

There are, however, many species of buttercup and this post will look at the creeping buttercup (Ranunculus repens). As the photo below shows, the sepals are not reflexed, but are spreading - meaning that they follow the line of the petals instead of curving back upon themselves, which is what the sepals on the bulbous buttercup do.

Another indicator that you're looking at a creeping buttercup are the runners, called stolons, that the parent plant sends out as a way of vegetative reproduction. When looking at the leaves of the plant you will see that the stem results in three leaves, with the middle leaf on a stalk. The leaves are lobed, but not as deeply as the meadow buttercup.

In the photo above, I have taken out some of the flower parts so that we can have a good look inside the flower. The outer whorl being the sepals, with the next whorl in being the lovely bright yellow petals, which have nectaries at their base. Just inside the petal whorl are the many stamens that provide the pollen. The centre of the flower being the carpels that are separate from each other and each contain a single ovule.

The photos below show a single petal with the guiding lines for pollinators, which lead to the nectary. The next photo shows the fertilised flower. All of the sepals, petals, and stamens have fallen off as they serve no further purpose. The flower head is left with what are called achenes, which on the creeping buttercup are hairless and have a slightly curved beak. Achenes are single-seeded nutlets, which are each formed by a single carpel.

If we take off one side of an achene, we can see inside to the developing seed. The achene is a common type of dry fruit. At maturity it does not open, which makes it a indehiscent fruit. Strawberries and sunflowers are examples of plants that have the same type of fruit.

20x microscope view

Below is a view under the microscope (20x), we can see that the pollen is, at least at this magnification, spherical.

In our final microscope view we can see the anther. It has two lobes providing the pollen.

20x microscope view

There have been a couple of interesting pieces of research done with buttercups in recent years. Firstly, the ability for the buttercup flower to shine under chins. Secondly the research done showing a genetic mutation in creeping buttercups that helps in dating meadows. Both of these will be discussed in part two of this short study, available next week.