What Are Ridgeforms
Female Orchid Classification System
The following section is foundational and goes to the heart of FOCS. It is the discussion and illustration of the concept and demonstration of ridgeforms and to a lesser extent, fusions. Ridgeforms are used as the defining characteristic in classifying an orchid as either simplex or complex, so proficiency in identifying ridgeforms is crucial to master. Ridgeforms have many patterns and for this reason, a large number of the most common examples are presented.
Ridgeforms and Fusion
In its simplest construct, a ridgeform is a ridge of tissue, which in the simplest cases, may parallel the sheath and/or labium. It has no underlying structure like the clitoris covered by the clitoral sheath and can completely disappear if the surrounding tissue is stretched. Ridgeforms are very common and distinctive. The word ridgeform is a newly created word to describe a unique morphological feature of orchids.
Again, its simplest form, independent origin ridgeforms have a beginning anywhere beside the sheath and usually run parallel with the sheath and labia. This type of ridgeform commonly fuses with the labium (prime or lesser), and thus the new morphological term of fusions. Ridgeforms and fusions can be described together. A ridgeform can exist without a fusion point but a fusion always occurs with a ridgeform. Examples illustrated below.
More examples illustrate independent ridgeforms that fuse at various positions of the labium.
In the above examples, the overriding principle is that any ridgeform that originates at the side of the clitoral sheath is designated an independent ridgeform. When the clitoral sheath splits into two or more streams, those splits are also ridgeforms but the orchid is designated as bifurcated or bifurcation illustrated in a following section.
Hood Ridgeform
The shear range of hood variations makes it difficult to determine whether or not, in some orchids, the hood is a standard (inverted V) or is a ridgeform. Below are examples where the hood clearly has ridgeforms.
Pseudo Hood Ridgeform
Another common and distinctive ridgeform is the pseudo hood ridgeform. A pseudo hood is typically an inverted V shape on the sheath above (north of) the actual hood. One or both arms of the V extend into a ridgeform that fuses with the labia as illustrated below.
Hairpin Ridgeform
A ridgeform and fusion that is common, distinctive, and easily identified is the hairpin ridgeform. In these instances, the ridgeform may originate as a tributary from the sheath (bifurcation discussed later), or may have an independent origin beside the sheath, that fuses with one of the hood, labium prime or labium lesser. It literally forms a loop or hairpin. The hairpin can fuse with the labium as in previous examples, or transition / transform into the labium as illustrated below.
Ridgeform Pocket
Another common ridgeform characteristic is the ridgeform pocket. The ridgeform usually originates from the sheath or hood and can rejoin (fuse) the sheath or labia. This ridgeform is distinctive in that it forms a noticeable pocket.
A ridgeform pocket is not an exclusive form. It is just a further description of a ridgeform. For example, a hairpin or pseudo hood ridgeform could also form a pocket so could be referred to as hairpin ridgeform pocket or pseudo ridgeform pocket. Examples below.
