A violet-ant mutually beneficial symbiosis

 

Sweet violets Viola odorata produce two types of flower - the familiar scented kind that are amongst the first wild flowers to appear in spring and are pollinated by bumblebees, and a summer cleistogamous version that remains as a closed bud and self-pollinates without the intervention of insects. Insect pollination in early spring can be a chancy, hit-or-miss affair but, come what may, the cleistogamous flowers aways produce seeds in early autumn. This is a seed capsule of one such that I found in the garden, splitting open in three segments to release its seeds. Each seed has a small, white, oily attachment, an elaiosome, that ants find irresistible. They carry the seeds away so, if you grow violets in a garden, seedlings are likely to appear in unexpected places.

I’ve sown some freshly collected sweet violet seeds now, because they’ll need vernalisation, subjection to the freezing temperatures of winter, to break their dormancy.

 

Butterbur going to seed

It seems like no time at all since the first butterbur flower spikes began to appear along riverbanks in early spring, but now they are ready to shed their seeds. These impressive seed spikes were growing in woodland beside the river Wear at Durham Wildlife Trust's Low Barns nature reserve last week.

There are separate male and female plants of butterbur, which spreads via creeping underground rhizomes. Large areas of England have only male plants, thought to have been transplanted long ago outside of the plant's natural range by beekeepers, because butterbur is a prolific producer of pollen and nectar for honeybees. In Country Durham we have both sexes of the plant so seed set is common, although the female plants only become conspicuous when they elongate and produce these tall seed heads in late spring.