Common Twayblades

Tom had a quick trip up to Headend Quarry this afternoon, before the rain, in search of orchids. While the chalk fragrants and common spotted orchids are at their best, the highlight was certainly the common twayblades!

One individual was deformed, with some flowers being double headed with fully formed flowers (including sepals, petals and lips), except the stem and ovaries that were fused together. Other flowers on the individual were similar, in being double headed, except not all were fully fused. 

Double flowered individual.

While these deformities are one-off oddities, a named variant can also be found at Headend Quarry- var. trifoliata. While not uncommon, var. trifoliata is an interesting plant, with three leaves instead of the characteristic two. 

Also observed was the pollination of the common twayblade. Common twayblades are pollinated by ichneumon wasps, along with some other small insects such as sawflies. After being attracted by the flower's scent, the ichneumons would follow the nectar filled groove on the lip (seen in the images below as the dark streak up the center of the lip) to the pollinia which are then stuck to the wasp's head by the secretion of a sticky liquid. This can also be seen in the photographs below as a pale yellow blob (the pollinia) on the ichneumon's head.

Visiting ichneumon.

A different species of visiting ichneumon.

More ichneumon pollination.

As well as variation in the number of leaves and flower odities, common twayblades come in a surprisingly large number of colours, from pale, almost yellow lipped individuals, to very dark brown petaled.

A variety of colours.

The common twayblades, while understated, are spectacular, especially when there are large stands of them, standing tall above the lower vegetation. The number of plants has dramatically increased at the quarry, likely as a result of increasing vegetation making the habitat more suitable. However, this increase in vegetation and lack of management has also lead to the likely (functional) local extinction of the frog orchid. Only one individual was found last year -click here-, and it has not flowered this year. ...and some more twayblade photos...