White and yellow flowers
Spring is in full swing now, thank goodness. It felt like a long time coming this year.
Over the last couple of months around the village, looking at the hedgerows, field margins, road verges and wilder parts of our gardens you’ll probably have noticed some of the spring flowers brightening up our days.
Early on, we saw primrose Primula vulgaris and daffodil Narcissus pseudonarcissus, then lesser celandine Ficaria verna, wood anemone Anemone nemorosa and goat willow Salix caprea; a little later came greater stitchwort Stellaria holostea, dandelion Taraxacum officinale, gorse Ulex europaeus and broom Cytisus scoparius and into May, ramsons Allium ursinum and creeping buttercup Ranunculus repens to name a few.
The thing that these plants have in common, whether herbaceous, shrub or tree is that they all have yellow or white and yellow flowers. Most of these plants are woodland or woodland edge species and in order to reproduce through seed, need to flower and attract pollinators before the woodland canopy comes into leaf and shades them out.
Most of these plant species will have markings on their petals that cannot be seen with the human eye but can be detected by the highly specialised eyesight of pollinating insects. These markings direct insects to the nectar within the flower and ensure that pollen is collected in the process of feeding. Flowers will have different markings particular to their species to try to encourage the pollinating insect to visit many flowers of the same species and subsequently deposit the (male) pollen from the stamen onto the stigma (female part) of flowers in the process.
Reproduction is pretty complex with flowering plants, most plants are hermaphroditic having male and female parts in the same flower, and can reproduce with the male and female parts of the same flower; some, reproduce using separate male and female flowers on the same plant (monoecious - meaning ‘one house’) and other still, such as the goat willow above, reproduce by having one plant of the species with only male flowers, and another with only female flowers (dioecious), the pollinating insect must visit different sexed plants of the same species in order to reproduce. Holly Ilex aquifolium, is also dioecious and famously, will only have the berries on the female plants, so if you have a holly that doesn’t have berries in autumn / winter, this may be why.
The shape and structure of a flower also guides the appropriate insect towards it and this plays another part in attracting insects to the plant's flower, efficiency of reproduction is key and all of this needs communicating to the pollinating insect. For the spring flowers, their biggest issues are that the number of pollinating insects can be very low, as can the light levels compared with summer. Yellow has been shown to be a highly effective colour to stand out in these conditions and subsequently is a good strategy to attract insects towards them.
The process by which flowers grow, and know when to open their flowers is known as photoperiodism and as we get into May and light levels rise and lengthen many more plants are opening up their flowers and putting out their advertisements. Many of these will also have colours through the red and blue spectrum and may be showier to be attractive amongst increased competition. Most pollinating insects are known as generalists, which means that they don’t have a specialist relationship with one plant in particular and can feed from a variety of different plant flowers, though different pollinators are attracted to different colours and scent and adapted to flower shape. This month we will of course see the iconic bluebell in the woodland around, we’ll also see columbine Aquilegia vulgaris and comfrey Symphytum officinale to name a few. How hard they have to work for a living..
Image by Andreas Lischka from Pixabay
