Monday, 24 June 2013

Spotted Orchids (better late than never)

I saw a few spotted orchids during a rainy walk yesterday, so I thought I would try to get a representative sample while the lowest flowers were just opening. In my opinion, this is when an orchid plant looks best: once the higher flowers are open, the lower ones can look very untidy and spoil the overall look. As usual, I will give my assessment of what species are present in each specimen, with rationale. The three 'species' photographed are Common Spotted Orchid (CSO), Heath Spotted Orchid (HSO) and Northern Marsh orchid (NMO). 

Characteristics used:

CSO has white to pink flowers with a clearly pointed centre lip and pointed outer lips
HSO has white to pink flowers with a continuous frilled lip and only a small point, if present
NMO has purple flowers with a smooth continuous lip. Flowerhead usually squat. Flowers earlier than the previous two species.

This first one looks to be pretty well 50/50 CSO/HSO due to the pale colour and the fringed outer lips with a spiked centre lip.

Common Spotted Orchid x Heath Spotted Orchid

This specimen looks to be pure CSO due to the three-pointed lip:

Common Spotted Orchid

This appears to have all three parents, with a central tooth, frilled outer lip and darker colour:

Hybrid Spotted Orchid
This appears to be mostly NMO, due to the darker colour and continuous, unfrilled, toothless lip, but the upper flowers are tending to pale and the spike is quite tall:

Hybrid Spotted Orchid
This paler specimen is mostly CSO, with a touch of HSO due to the slightly frilled/rounded outer lip:
This looks to be a very clean NMO, due to the short spike, already fully-open flowers, darker colour and continuous lip, but there is a tiny hint of frilling, so we have to consider some HSO:
A good, clean CSO (triple teeth with almost no frilling):

Common Spotted Orchid
This is clearly part CSO (long central tooth) and HSO (frilled outer lips):
Note that the central flower in the above spike is still rotating clockwise into its 'upright' position.

This last shot shows, I think, a triple hybrid between HSO, CSO and NMO. There is a clear frill round the lip, there is a central tooth and the colour is quite dark with a shorter spike:

Triple hybrid Spotted Orchid
I cropped that last shot to include the Heath Woodrush on the left.

Please note: the differentiation between Dactylorhiza orchids is contentious at best and uncertain at worst. I also believe that they tend to vary according to micro-habitat, with specimens with wet feet tending towards HSO and those with dry feet tending towards CSO. The variability in your area might well be different.


The Weaver of Grass said...

Again I shall direct my orchid spotting friend to your site to look at these photographs Stuart. Excellent.

Gill said...

I agree absolutely on the fact these orchids are at their most attractive as they open. I'm surprised your NMO aren't darker - none of those shown have what I consider to be the classic "dark wine-purple" of classic NMO (which according to something I've been reading is itself derived as a tetraploid hybrid between early marsh and one of the "spotted orchids", CSO I think. I'm interested your NMO flower earlier than the other dactylorchids - not something I'd picked up, though it makes sense if one of its ancestors is early marsh.

stuart dunlop said...

Gill: I think the ones which are mostly NMO are pretty accurate in colour: darker background colour than CSO or HSO ever reach. Interesting about Early Marsh (EMO) being one of the parents of NMO: I have always seen a similarity in the shape of the flower and pattern of the dots. Both remind me of a vertical spotty bow-tie. NMO hereabouts is intermediate in date between EMO and CSO/HSO (although closer to CSO/HSO), so that would tie in, too. An orchid geneticist tells me that Frog Orchid seems to be the ancestor of all of the Dactyl orchids, since it is genetically closer to them than they are to each other. This is clearly complex (but very interesting) ground.