Taxonomy of the <i>Poa laxa</i> group, including two new taxa from Arctic Canada and Greenland, and Oregon, and a re‐examination of <i>P</i> . sect. <i>Oreinos</i> (Poaceae)
Bibliographic record
Abstract
The Poa laxa Haenke species group, comprising four alpine – arctic taxa in P . sect. Oreinos , has a complicated and confusing taxonomic history. Here we re‐examine the taxonomy of the group and section based on sequences of three plastid and two nuclear ribosomal DNA markers. Poa laxa s.l. resolved in a clade with species of sections Abbreviatae, Oreinos, Stenopoa , and Tichopoa . In the plastid analyses, Poa laxa s.s. (type of sect. Oreinos ) was placed in a subclade with P. glauca and other sect. Stenopoa species, while all other P. laxa s.l. taxa were placed in a subclade with species of sect. Abbreviatae . We maintain P. laxa s.s. (mainly 2n = 28) of west–central Europe in sect. Oreinos , while the other P. laxa s.l. taxa from northern Europe and North America (all 2n = 42 or higher ploid) are referred to P . sect. Abbreviatae . In North America only one collection of the northern European P. flexuosa subsp. flexuosa is accepted (Greenland, Jensen's Nunatakker), and P. flexuosa subsp. fernaldiana is accepted based on populations in eastern Canada and northeast USA. A new subspecies, P. flexuosa subsp. consauliae , is described from eastern Arctic Canada and Greenland ; its variable morphological characteristics suggest introgression with P. glauca and it is predicted to be apomictic. Rocky Mountain P. laxa subsp. banffiana is treated as P. banffiana . Oregon material formerly considered to belong to P. laxa s.l. is named P. wallowensis. Poa sect. Oreinos is thus found to be polyphyletic, and is here emended to comprise only three continental European species, including P. laxa . Lectotypes are designated for P. aspera var. laxiuscula, P. fernaldiana, P. flexuosa , and P. laxa var. debilior . New chromosome numbers are reported for P. flexuosa subsp. consauliae (ca 2n = 42), and P. glauca (2n = 63) from Baffin Island. A key to the species and subspecies found in North America is given.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".