Introduction
When Carl Luer began his extensive work on the Pleurothallidinae, very little was known about them. Over nearly half a century, Luer organized the subtribe’s extraordinary hyperdiversity into a coherent morphological system, giving formal structure to a group that had previously been poorly defined.
Multiple, subsequent, peer-reviewed phylogenetic studies have included these species, yet none has produced a well-supported phylogeny that resolves internal lineages across the group.
Even so, those phylogenetic studies have been used to dismantle much of Luer’s morphology-based framework and many distinct species have been repeatedly misidentified, treated as subspecies, lumped into unofficial species complexes, or incorrectly reduced to synonymy.
In law, medicine, and many other disciplines, decisions are expected to be supported by documented procedures, evidentiary standards, and precedent. Taxonomy, however, lacks the kinds of standardized evidentiary procedures used in other disciplines.
The International Code of Nomenclature for algae, fungi, and plants (ICN) establishes internationally accepted rules governing the naming of taxa, but it does not provide a corresponding framework for interpreting biological evidence, determining species limits, or establishing the evidentiary threshold required to alter a taxonomic classification.
The American Society of Plant Taxonomists (ASPT) has argued that nomenclatural changes should require a “strong preponderance of evidence” and cautions specifically against changes derived from poorly supported or conflicting phylogenetic results. This represents an articulated professional norm rather than an internationally codified evidentiary standard.
The International Association for Plant Taxonomy (IAPT) is genuinely an international organization. However, like the ICN, its international role is principally concerned with nomenclature and the infrastructure of taxonomic science; it does not provide an international evidentiary code governing taxonomic interpretation.
There is a misconception that Royal Botanic Gardens, Kew validates research through Plants of the World Online (POWO). However, Kew is not an authority that establishes rules for interpreting biological evidence, determining species limits, or establishing the evidentiary threshold required to alter a taxonomic classification.
POWO is a taxonomic database that reflects published taxonomic research. An “accepted” species status simply confirms that the name used in the most recent, validly published research meets the rules defined by the ICN.
Without a standard framework, previous determinations do not establish a precedent requiring comparable morphological or biological evidence to be interpreted consistently in subsequent cases. Therefore, the interpretive process essentially begins again with each new species description or taxonomic revision.
Researchers employ numerous competing species concepts to examine the same evidence and often arrive at completely different conclusions regarding species boundaries, synonymy, generic placement, or evolutionary relationships.
Peer-review also lacks the standardized procedures necessary to ensure consistent application by relying upon the judgment of a small number of anonymous reviewers who may be biased because:
• they support a competing hypothesis
• they have professional relationships with researchers in the field
• they view evidence through a particular methodological lens
Through forensic pattern recognition and evidentiary analysis, the research presented here reveals that the extraordinary hyperdiversity of subtribe Pleurothallidinae, which has commonly been dismissed as trivial intraspecific variation, is a biomechanically stratified, living record of directional evolution.