An expanded <i>Pappostipa</i> (Stipeae, Poaceae) includes a lineage of South American species with plumose-like awns
Bibliographic record
Abstract
Abstract Generic delimitation within the tribe Stipeae has been a dynamic process since the late 1980s. In this study, we focus on a morphologically cohesive group of Jarava species with plumose-like awns that previous phylogenetic studies suggested were sister to the genus Pappostipa and only distantly related to Jarava sensu stricto. To test this hypothesis, we broadened species sampling, analysed lemma epidermal patterns, and performed molecular phylogenetic analyses using the nuclear ITS region and three plastid (rpl32-trnL, rps16-trnK, rps16 intron) markers. Phylogenetic results confirmed the close relationship of Jarava species with plumose awns (i.e., the Ptilostipa clade) to species of Pappostipa, forming a well-supported clade (C subclade). This result is supported by lemma epidermal patterns in the Ptilostipa clade that are similar to the ‘Maize-like’ pattern of the Achnatherum subtype found in Pappostipa. Consequently, we expand Pappostipa to include three species of Jarava (i.e., Pappostipa neaei, comb. nov., P. pogonathera, comb. nov., and P. psylantha, comb. nov.) and we place them in a new section, Pappostipa sect. Ptilostipa, sect. nov. Moreover, we provide new diagnostic features for Pappostipa, including drawings and photographs illustrating floret morphology, lemma epidermal surfaces, species’ habit, and notes on distribution.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".