If you are a regular reader of this blog, you may be aware that in the five years that Lindsay and I have lived on our property in North Liberty, Indiana, we located two species of orchids on the land formerly used as hog pasture and currently in an old-field state. First was Ragged Fringed Orchid (Platanthera lacera) on 4 July 2009, and then on 4 September of that same year I came across Purple Twayblade (Liparis liliifolia) while conducting transect/quadrat sampling on our property. Two orchid species on our property! Two species, that is, until this spring.
Sometime this March I noticed the leaves of an orchid along the trails through our property. I immediately recognized the orchid as a twayblade (Liparis), but the leaves seemed more narrow than the Purple Twayblade I'd found on our property two-and-a-half years prior. I decided to keep an eye on this orchid with hopes that it would develop flowers. Then, one day in late May, Lindsay was walking Bootypants and noticed that the orchid had produced flowers. She called me at work to let me know, and with much anticipation, I asked if the flowers were purple. To my amazement and delight, the answer was "no, they're green." I was aware of the green-flowered form of Purple Twayblade (called Liparis liliifolia forma viridiflora), but I also knew that Green Twayblade (Liparis loeselii), which has narrower leaves than Purple Twayblade, has green flowers. I couldn't wait to get home and walk (it turned out to be more of a jog) to the far western end of our property to have a look for myself.
Sure enough, that excited confusion that I experienced on 4 July and 5 September 2009 was repeated as I gazed upon a single Green Twayblade plant in flower! During the sampling I conducted on our property on 5 September 2009, I did see a single narrow-leaved twayblade plant without flowers along the northern boundary of our property that I thought looked like Green Twayblade, but I didn't expect to see this species that normally grows in calcareous wetlands (such as fens, pannes, and sedge meadows) in our weedy old-field, so I assumed that it was probably just a narrow-leaved Purple Twayblade. I went back to that location the following year and couldn't relocate the plant. Now I am fairly convinced that the plant I saw on 5 September 2009 after already finding Purple Twayblade on our property was in fact the the same species that I saw in flower on 25 May 2012, Green Twayblade.
Although Green Twayblade (also known as Loesel's Twayblade) usually is found in calcareous wetlands, it is not unprecedented to find it in a shrubby old field such as ours. Homoya (1993) mentions accounts of this species in dry, brushy old-fields (such as ours) and young regrowth forests, but these accounts seem to be rare. Maybe that's because this species is small and inconspicous and old-fields and young regrowth forests aren't on the top of the list for people to botanize. Or maybe, as Homoya (1993) suggests, this species is expanding its range south and into different habitats. Or maybe, just maybe, there is a third species of twayblade in the Great Lakes region that grows in drier conditions and that has yet to be described.
For more information on Green Twayblade, see my recent post at Get Your Botany On!.
Anyone care to venture a guess as to what the next species of orchid to surface on our property will be? I would say that I would be surprised to find another species, but after what we've seen so far, I wouldn't be telling the entire truth.
Homoya, M.A. 1993. Orchids of Indiana. Indiana Academy of Science. pp. 136-139.