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Tuesday, 20 June 2017

Flowers that must have a fungal partner.

Yellow Bird's Nest Monotropa hypopitys found at the Ashpits (between Burry Port and Pwll) in the last week. The flower has no chlorophyl (no leaves of any kind) but depends on a mycorrhizal fungus for 'sugars'.  The fungus (at this location) is Tricholoma cingulatum Girdled Knight which is mycorhizal with species of Willow.
As the flower has no leaves it does not need to seek the light so may be found in dense vegetation ---- more likely to be found by those looking for fungi than botanists!

There are four scapes (= a leafless flowering stem) in the photo --- one on the R (stick pointing), one in the centre by dead leaf and two by the curved stick on the left.  
I have not seen the flower nor the Tricholoma in the area for several years but assumed both had 'gone'.  If the fungus goes, the flower goes as it is unable to obtain sugars independently.

This was a photo from the Ashpits some years ago with new scapes and some old ones with seed capsules.

One scape with some Girdled Knight, Tricholoma cingulatum --- note the feeble ring on the stipe of the fungus.  Few Tricholoma have a felty ring and T.cingulatum is the only greyish one --- others are more brown and larger species.


Yellow Bird's Nest has 'dust seeds' with no food reserve to feed on for germination so the dust seeds need to meet its fungal partner to germinate and then throughout its life.  This form of existence is called 'mycoheterotrophy'--- dependent on fungi throughout life for sugars.  Other flowers have dust seeds --such as Witergreens --- Pyrola species as the Lesser Witergreen, Pyrola minor, above, also present at the Ashpits. As I got up from lying down to take the above 'close-up' I found my hand was almost touching another Yellow Birds-nest scape which I had not noticed.  Pyrola's do have green leaves so can photosynthesize once leaves have formed --- mixotrophs. 
 Orchids,such as the Twayblade Listera ovata, below, also have dust seeds so depend on meeting a fungus for germination.  Orchids without green leaves, such as the Bird's-nest Orchid - Neottia nidus-avis (sometimes seen at a spot at Gelly Aur) are 'mycoheterotrophs' needing a fungal partner throughout life.

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