It is Leap Year’s day and we are emerging from a mild but very wet winter in West Sussex. Gardening is impossible; the lawn and both meadows are quagmires. I would like to be able to give the meadows a high cut with the lawn mower because the grass has been growing happily all winter, but they are far too squelchy and would turn into mud.
The first of my winter dormant greenhouse orchids to appear are some Heath spotted orchids (Dactylorhiza maculata). My pots of Common spotted orchids (Dactylorhiza fuchsii) are a little behind them, but also beginning to show. The two species are so similar it is often hard to tell them apart. One could be forgiven for thinking they are versions of the same thing; Heath spotted when found on the acid soils of heaths, moorlands, peat bogs and damp meadows, and Common spotted when found in a whole variety of neutral and alkaline soils such as chalk downland, woodland edges, roadside verges etc.
It is well established, however, that they are two different species. There is some overlap in habitat in that Common spotted can also be found on mildly acid soils. Both are very widely distributed throughout the U.K. So, how to tell them apart?
The most obvious difference is the 3-lobed lip of the flower: Heath spotted has the look of a wide, rounded lip with frilly edges and is often very pale pink or white with rather faint markings of purple dots, dashes and lines. The cuts between the lobes are short and the central tooth is narrow and doesn’t project far beyond the outer two lobes. Common spotted has much deeper cuts between the lobes so that the wider, central lobe appears like a long “tooth” sticking out. The lip often has much heavier purple markings with larger dots, dashes, and sometimes double loop lines.
However individual plants often do not conform to ideal templates. There is a lot of natural variation in both species, and also hybrids between the marsh orchids occur frequently. The lip doesn’t always have that “typical” appearance of one species or the other. Some other features may differentiate: the leaves of Common spotted tend to be wider and more heavily spotted. In Heath spotted they tend to be narrower and more pointed with fainter spotting, but again not always a very reliable feature. In Common spotted the lowest leaf is short, and bluntly rounded, but not so in Heath spotted.
It all makes for endless amusement.
Photos: 1. Heath spotted orchids emerging, 2. Heath spotted orchid on an acid heath, 3. Common spotted orchid in my garden meadows
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