A molecular phylogeny and new subgeneric classification of <i>Sporobolus</i> (Poaceae: Chloridoideae: Sporobolinae)
Bibliographic record
Abstract
Abstract The grass subtribe Sporobolinae contains six genera: Calamovilfa (5 spp. endemic to North America), Crypsis (10 spp. endemic to Asia and Africa), Psilolemma (1 sp. endemic to Africa), Spartina (17 spp. centered in North America), Sporobolus (186 spp. distributed worldwide), and Thellungia (1 sp. endemic to Australia). Most species in this subtribe have spikelets with a single floret, 1‐veined (occasionally 3 or more) lemmas, a ciliate membrane or line of hairs for a ligule, and fruits with free pericarps (modified caryopses). Phylogenetic analyses were conducted on 177 species (281 samples), of which 145 species were in the Sporobolinae, using sequence data from four plastid regions ( rpl32‐trnL spacer, ndhA intron, rps16‐trnK spacer, rps16 intron) and the nuclear ribosomal internal transcribed spacer regions (ITS) to infer evolutionary relationships and provide an evolutionary framework on which to revise the classification. The phylogenetic analysis provides weak to moderate support for a paraphyletic Sporobolus that includes Calamovilfa, Crypsis, Spartina , and Thellungia . In the combined plastid tree, Psilolemma jaegeri is sister to a trichotomy that includes an unsupported Urochondra‐Zoysia clade (subtr. Zoysiinae), a strongly supported Sporobolus somalensis lineage, and a weakly supported Sporobolus s.l. lineage. In the ITS tree the Zoysiinae is sister to a highly supported Sporobolinae in which a Psilolemma jaegeri–Sporobolus somalensis clade is sister to the remaining species of Sporobolus s.l. Within Sporobolus s.l. the nuclear and plastid analyses identify the same 16 major clades of which 11 are strongly supported in the ITS tree and 12 are strongly supported in the combined plastid tree. The positions of three of these clades representing proposed sections Crypsis, Fimbriatae , and Triachyrum are discordant in the nuclear and plastid trees, indicating their origins may involve hybridization. Seven species fall outside the major clades in both trees, and the placement of ten species of Sporobolus are discordant in the nuclear and plastid trees. We propose incorporating Calamovilfa, Crypsis, Spartina, Thellungia , and Eragrostis megalosperma within Sporobolus , and make the requisite 35 new combinations or new names. The molecular results support the recognition of 11 sections and 11 subsections within Sporobolus s.l.; four sections are new: Airoides, Clandestini, Cryptandri , and Pyramidati ; three sections are new combinations: Calamovilfa, Crypsis , and Spartina ; four subsections are new combinations: Calamovilfa, Crypsis, Ponceletia , and Spartina ; seven subsections are new: Actinocladi, Alterniflori, Floridani, Helvoli, Pyramidati, Spicati , and Subulati ; 30 new combinations in Sporobolus : S. aculeatus, S. advenus, S. alopecuroides, S. alterniflorus, S. angelicus, S. arcuatus, S. bakeri, S. borszczowii subsp. acuminatus, S. borszczowii subsp. ambiguus, S. brevipilis, S. coarctatus, S. cynosuroides, S. densiflorus, S. factorovskyi, S. foliosus, S. hadjikyriakou, S. ×longispinus, S. maritimus, S. megalospermus, S. michauxianus, S. minuartioides, S. niliacus, S. pumilus, S. rigidus, S. rigidus var. magnus, S. spartinus, S. schoenoides, S. ×townsendii, S. turkestanicus , and S. vericolor ; and five new names in Sporobolus : S. arenicola, S. ×eatonianus, S. hookerianus, S. mobberleyanus , and S. vaseyi are made. Lectotypes are designated for Crypsis factorovskyi, Heleochloa ambigua , and Torgesia minuartioides.
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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 | 0.002 | 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".