Wednesday, September 26, 2012

Variation in the Spotted Coralroot

Corallorhiza maculata, the Spotted Coralroot, is not as variable as the Western Coralroot, Corallorhiza mertensiana, but there is still considerable variation here in the Pacific Northwest, including three varieties and five named color forms.  They are:

Variety #1 - the Spotted Coralroot (found in both the eastern and western United States and Canada.  This variety is distinguished by the lip which has parallel sides and by a later bloom time where it grows together with the Western Spotted Coralroot.

Corallorhiza maculata var. maculata - bronzy stems and purple spotted lip
("bronzy" covers considerable color variation in this case)

Corallorhiza maculata var. maculata fma. flavida - yellow stems and unspotted lip
(this is a form we have not seen)

Corallorhiza maculata var. maculata fma. aurea - yellow stems and spotted lip
(the forma aurea name is my own since this is not a named form)

Corallorhiza maculata var. maculata fma. rubra  - red stems and red-spotted lip
(in the Northwest this appears to us to be the most common form)

Variety #2 is the Western Spotted Coralroot, which is found across Canada but only in the Western United States.  This variety is distinguished by the rounded end or mid-lobe of the lip and by a slightly earlier bloom time where it grows with the ordinary Spotted Coralroot.

Corallorhiza maculata var. occidentalis - bronzy stems and spotted lip
(here again "bronzy" covers considerable color variation)

Corallorhiza maculata var. occidentalis fma. aurea - yellow stems and spotted lip

Corallorhiza maculata var. occidentalis fma. immaculata - yellow stems and unspotted lip

Corallorhiza maculata var. occidentalis fma. punicea - red stems and spotted lip

Unamed Color Forms
(the last looks a lot like var. ozettensis)

Variety #3 is found only in Washington and British Columbia, was only recently described (2001) and is quite rare, found only in a few locations on the Olympic Peninsula, Whidbey Island, Vancouver Island and the middle of British Columbia.  It is known as the Ozette Coralroot after the location in which it was first found.  This variety is distinguished by the unspotted lip, greenish flowers and flowering time.

Corallorhiza maculata var. ozettensis - purple-red stems and unspotted lip

The third variety is very distinct, but the other two seem to grade into each other and it is not easy to tell them apart unless one visits repeatedly an area where both grow.  Then it becomes evident that the Spotted Coralroot blooms slightly later than the Western Spotted though there is some overlap, and tends to have smaller flowers and predominantly red stems (fma. rubra), at least in this area.

As can be seen from the photos, there is considerable variation also in flower color and in the spotting of the lip and flowers.  While some flowers are free of spotting except on the lip others are spotted especially on the petals and the lips vary from fine and dense spotting to sparse and coarse, many lips having almost no spotting on the mid-lobe and others a single reddish-purple spot.

this is variety maculata

these are variety occidentalis


Friday, September 21, 2012

Color Forms of the Western Coralroot

The Western Coralroot, Corallorhiza mertensiana, is aptly named since it cannot be found east of the Rockies either in the United States or in Canada.  In the west it is quite common and when found is often growing in large numbers.  It can be found on very dark forest floors where nothing else is growing and then especially in the paler color forms stands out vividly.

We have seen this species in many different locations and in many different color forms, the different color forms often growing among each other and apparently hybridizing with one another, with every possible color combination and shade to be seen.  These different color forms, which make the species so interesting are the subject of this blog post.

There is a form of the this species is a deep and rich reddish purple color, with stem, flowers and lip nearly uniform in color, only the light yellow tip of the column and some paler markings on the lip interrupting the uniformity of color.  This variety, when we have found it, seems to grow without any other color forms, and is perhaps worthy of being considered a named form.

This appears closest to the ordinary form, described by Paul Martin Brown as having reddish-purple stems, bronzy-purplish tepals (sepals and petals) and a bright purple lip.  We have found flowers more or less matching this description but they are no more common than any other color in the areas we've searched, and even with them there is considerable variation of color.

There are two named forms, forma albolabia, a form without any purple coloration at all.  We have seen this once, on the Thunder Creek Trail in the North Cascades.  Its pale yellow color and white lip are very striking, but it is also the rarest of the different forms, at least in our experience.  In our opinion this is a legitimate named form and is very distinctive.

The other named form is forma pallida which Paul Martin Brown describes as having stems and flowers of palest lavender with a bright purple lip.  While we have seen many paler colored plants there are few that exactly match this description and much variation of flower, stem and lip color even among those paler forms.  We have some doubt that this is a legitimate named form.

When we've found different color forms growing together there is endless variation, though we never found the dark purple form in such locations.  In these areas the stem color ranges  from a deep reddish purple to dark pink and dark tan.  The stems of the lighter forms range from off-white, to pale yellow, pale lavender and tan.

Lip color ranges from nearly uniform dark pink and purple, to lips that are more white than colored with purple or dark pink edges and marks.  We've found purple or dark pink lips with a white splotch on the end, white with purple edges and a dark pink splotch in the middle, white with purple spots, and dark pink with darker purple markings.

The color of the tepals in these intermediate  forms ranges from the bronzy-purple described above, to lavender, tan, pink and pale yellow, some without spotting on the sepals and some with more or less spotting.  And combined with the lip these are found in every possible combination, making it rather fun to examine them and photograph them.