Seed morphology, polyploidy and the evolutionary history of the epiphytic cactus Rhipsalis baccifera (Cactaceae)
Bibliographic record
Abstract
A SEM survey of seed, stem, stomata, and fruit characters was conducted to investigate patterns of infraspecifi c variability in Rhipsalis baccifera.New and Old World seeds were analyzed to assess the taxonomic value of their morphological features and the presence of gigas characters in polyploid versus diploid subspecies.The seeds are mussel-shaped and correspond to the Rhipsalis-type.Old World representatives have primarily oval seeds, whereas narrowly oval to oval seeds are more common in New World accessions.The seed coat is glossy, smooth, and without secondary sculpturing.The cell outline is slightly irregular with an overall elongate to rectangular shape.Cell size increases from the hilum-micropylar region to the apical portion of the seed.Seed and cell size increase with increasing level of polyploidization, its maximum expression occurring in polyploid African populations.It is likely that increase in seed size in the Old World is correlated with polyploid cytotypes.An increase in stomatal cell size is not evident with an increase in chromosome number, though stem and fruit size and the number of stomata are higher in the Old World polyploid subsp.horrida.The existence of smaller seeds in Paraguay and northern Argentina suggests that this South American region is the center of origin of R. baccifera, from where it radiated to North America and the Old World via eastern Brazil.We hypothesize that the extensive geographic distribution of R. baccifera in the New and Old Worlds has been possible due to reproductive strategies, progressive and recurrent cycles of polyploidy and dispersal events by migratory birds.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".