Monday, 26 June 2017

Post-flowering fate of Man Orchids at Ufton Fields.

Ufton Fields, a Warwickshire Wildlife Trust reserve, has a small population of Man Orchids (Orchis anthropophora).  In late May we counted 5 flowering spikes among the 25 cages marking plants that are, or have at one time been seen, there. In addition 2 more plants were in bud.  There were no plants outside the cages.  Excluding one of the 5, which was spindly and frail the average height of a flower spike was 26cm with 27 flowers on average.
Man Orchid in Fruit

Ufton Meadows - Man Orchid Cages

A frail plant that simply withered

I went back this morning to see the fate of these plants.  Without the cages they would have been impossible to find in the developed sward.   Lady's bedstraw and St John's-wort were everywhere.

The two plants that were in bud did not develop and had died off, as had the frail plant.   This left 4 spikes which had developed fruits with a total of 34 seed pods. Including the frail plant there were originally 123 flowers, so the fruiting success was 28%.  The fruiting success of individual plants varied from 0 (the frail plant) to 42%.

Last week we carried out a similar exercise at Bernwood Meadows, but not very successfully.   In early May we counted the flowers on 174 flowering spikes of Green-winged Orchids (Anacamptis morio) which averaged 6.8 flowers per spike in a survey area we created.   We went back to count fruits, at lunchtime on one of the hottest days of the year last week.   This is not an excuse for the fact that we could only find 31 of the original 174 flowering plants.  Those had an averages of 3 seed pods and 7.9 flowers.  The apparent fruiting success was therefore 38%.   But what of the plants that we could not find, which appear to be those with fewer flowers?  The total number of flowers we counted was 1193 and the total seed pods we found was 93; on this measure the fruiting success was only 8%.   The survey at Ufton Fields shows that unless individual plants can be identified in flower then again in fruit, assessment of the fruiting success is extremely difficult.
Bernwood Meadows
Fruiting Green-winged Orchid


  1. Terry
    At Martins' Meadows I am carrying out an investigation into the longevity of A. morio and O. mascula and as part of this I am counting flowers per spike and fruiting success.
    I have three semi-permanent quadrats ( they have to be removed prior to the hay cut and then re-established later).
    The first quadrat is 2m X 2m had 13 O. mascula individuals, 10 of which had flower spikes. The number of flowers per spike ranged between 3 and 10 with a mean of 6.2. None of these produced any fruits at all.
    Also in this quadrat were 5 A. morio individuals. All had flower spikes. 1 was predated but the rest had flowers varying in number from 3 to 8 per spike with a mean of 4.4. Only 1 of these produced a fruit!
    The second quadrat is 2m X 2m with 22 individuals of A. morio but no O. mascula. All the A. morios had flower spikes and the number of flowers per spike ranged from 3 to 8 with a mean of 5.4. 4 had been predated (2 had a few flowers remaining). By fruiting 12 had been predated, and of the remaining 5 had no fruits at all and the rest had fruiting success ranging from 20% to 100% per plant (the 100% was for a single flowered specimen!). The mean of all the percentages was 41.6%
    The third quadrat is 4m X 4m with 12 individuals of A. morio but no O. mascula. 2 individuals did not produce flower spikes. The number of flowers per spike ranged from 5 to 15 with a mean of 8.5. None were predated so all that had produced some fruit pods.The fruiting success ranged from 8.3% to 100% per plant (the 100% was for the specimen with 15 flowers!). The mean of all the percentages was 47.1%
    The spring here was exceptionally dry with periods of extreme temperatures (both hot and cold) which may have hit the O. mascula in particular. The quadrats are in three quite different parts of the meadow.

    1. It looks as though you were able to identify individual plants which is much better than my approach. Next year I hope BBOWT will let me set up something similar to your approach at Martins Meadows, and ideally mark each plant, thus providing much more useful data. There are no Orchis Mascula at Bernwood (D. incarnata and fuchsii are the other orchids there), but I have been studying a population at Westwell Gorse but I had more success in finding the fruiting plants there, but again marking plants would be better. It is though quite a small reserve and there is a risk of labels being removed etc. Might be interesting to take the same approach on these two Oxfordshire sites and your Suffolk site to compare and contrast next year. I can get climate data from weather stations reasonably close.

  2. The above results are for 2017!