ORCHIDS OF TIREE AND COLL: HYBRIDS

Heath Spotted and Common Spotted Orchids are the most abundant species on the islands so it comes as no surprise that their hybrids Dactyloriza x transiens are also plentiful. They come however in a wide variety of shapes and sizes and it may be that some of the more dainty individuals have Hebridean Spotted rather than Common Spotted parentage.

Common Spotted x Heath Spotted

Hebridean Spotted x Heath Spotted

Early Marsh Orchid is common on the islands and thus the hybrid with Common Spotted Dactyloriza x kerneriorum is relatively frequently found. There are a number of old records from Coll described by Heslop-Harrison between 1947 and 1949, whilst more recently I have found this hybrid at a number of locations on Coll. Their appearance can vary depending upon which subspecies of Early Marsh Orchid is involved.

Common Spotted x Early Marsh coccinea

Common Spotted x Early Marsh incarnata

Hebridean Spotted x Early Marsh Orchid coccinea

Early Marsh Orchid hybrids with Hebridean Spotted Orchid obviously occur given the abundance of both species. This is a shot of a pair of Hebridean Spotted x Early Marsh Orchid coccinea taken on 3rd July 2011.

The hydrid between Common Spotted and Northern Marsh Orchid Dactyloriza x venusta has been recorded only once on Tiree (1990). This is not entirely surprising as Northern Marsh Orchid itself is scarce on Tiree. There are more records from Coll, particularly from the work of Heslop-Harrison in the late 1940's. I have only found two specimens in recent years, near Sorisdale in 2009 and at Totronald in 2011.

Common Spotted x Northern Marsh

Common Spotted Orchid also hybridizes with Heath Fragrant Orchid to produce what is known as Dactylogenia st-quintinii. There are records from four sites on Coll in the late 1940's, although none have been identified recently. I suspect this is because the hybrid looks very like some of the natural variants of Common Spotted that appear commonly on Coll, and has thus been overlooked.

Until recently there was only one record of the hybrid known as Dactyloriza x mixtum (Common Spotted x Frog Orchid) from 1947 at Breachacha on Coll. However in July of 2009 and 2010 one specimen was found and photographed by myself on the machair at Grishipol, Coll. The fact that it was a very small and delicate plant, along with its machair habitat suggest that perhaps one parent is more likely to be Hebridean Spotted Orchid than the more robust Common Spotted.

Common Spotted x Frog

Early Marsh Orchid comes in two subspecies on the islands and in the right habitat can be abundant. Not surprisingly then, hybrids with other species have been noted, both on Tiree and Coll. The hybrid with Heath Spotted Orchid Dactyloriza x carnea has been recorded on both islands in the past, and I have found several recently on Coll involving both sub-species of Early Marsh Orchid and thereby giving very different looking hybrids.

Heath Spotted x Early Marsh

The other Early Marsh Orchid hybrid to have been found on the islands is Dactyloriza x formosa, the hybrid with Northern Marsh Orchid. It was recorded by Heslop-Harrison at Sorisdale on Coll and Ceann a' Mhara on Tiree. There are no recent records.

Heath Spotted x Northern Marsh

Heath Spotted Orchid is abundant on both islands. The hybrids with Common Spotted and Early Marsh are discussed above, but there are also records of Dactyloriza x formosa, the hybrid with Northern Marsh Orchid, from Tiree and Coll in the late 1960's. I have found one specimen near Breachacha on Coll which I believe to be this hybrid (June 2010).

There is only one other hybrid that has been recorded and that is Gymnaglossum jacksonii, Frog x Heath Fragrant Orchid. There is one old record from Fasachd on Coll and a more recent one dicovered by John Bowler on The Reef, Tiree in 2006.