The rarest plants in Oxfordshire?

Situated in south Oxfordshire, just a mile from Goring is Hartslock, a small nature reserve managed by BBOWT. Here, not only does the chalk grassland hill provide excellent views of the Thames valley:
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It also provides the habitat for three of the rarest plants in Oxfordshire - the small monkey orchid (Orchis simian), so named as it's flowers form the shape of monkeys is found at this one site in Oxfordshire and at few in Kent and Yorkshire (although it is more common in Europe)
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Whilst there are several monkey orchids, this year there were only two lady orchids (Orchis purpurea)  - which may have been introduced to the site in the 19th century, as the plants share more DNA with those found in Europe then those found in the UK. 
Like the monkey orchid, it gets it's common name from the shape of it's flowers, they are said to resemble ladies - with a hat and a long dress.  Like the monkey orchid, it is found at a very few sites in the UK
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But what makes hartslock special is that it is the place in the UK where these two species of orchids have hybridised - producing a lady-monkey orchid (Orchis simia x purpurea) - producing an flowers with the hats of the lady orchid and a body similar to the monkey orchid:

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Like most hybrids, it is considerable taller than the two parent plants and whilst there are only two lady orchids in flower this year, there are several hybrids.  So maybe, over time, the hybrids will replace one of their parent plants.
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For more information on these fascinating plants, their location, when they flower and the rather sad history of the site, there is an excellent blog written by one of the reserve wardens http://hartslock.org.uk/blog/