DOI: 10.5061/dryad.qv9s4mwqr
title: Data from: Phylogeny does not predict the outcome of heterospecific pollen-pistil interactions in a species-rich alpine plant community

description: Premise: Co-occurring plant species that share generalist pollinators
 often exchange pollen. This heterospecific pollen transfer (HPT) impacts
 male and female reproductive success through pollen loss and reductions in
 seed set, respectively. The resulting fitness cost of HPT imposes
 selection on reproductive traits (e.g. floral color and shape), yet we
 currently lack strong predictors for the post-pollination fate of
 heterospecific pollen, especially within community and phylogenetic
 contexts.  Methods:  We investigated the fate of
 heterospecific pollen at three distinct stages of plant reproduction: 1)
 pollen germination on the stigma, 2) pollen tube growth in the style, and
 3) fertilization of ovules. We experimentally crossed eleven naturally
 co-flowering species in the sub-alpine meadows of the Colorado Rocky
 Mountains, across a spectrum of phylogenetic relatedness. Using
 generalized linear mixed models and generalized linear models, we
 evaluated the effect of parental species identity and phylogenetic
 relatedness on pollen tube growth at each reproductive stage. 
 Key Results: We found that heterospecific pollen tubes can germinate and
 grow within pistils at each reproductive stage, even when parental species
 are &gt;100My divergent. There was no significant effect of
 phylogenetic distance on heterospecific pollen success and no evidence for
 a mechanism that suspends heterospecific pollen germination or pollen tube
 growth within heterospecific stigmas or styles. Conclusions: Our results
 show that even in communities where HPT is common, pre-zygotic
 post-pollination mechanisms do not provide strong barriers to
 interspecific fertilization. HPT can result in the loss of ovules even
 between highly diverged plant species.
description: This is the raw data from the experimental crossing study
 associated with Cohen et al. 2024 published in the <em>American
 Journal of Botany</em>. One of the experiments was a
 semi-<em>in vivo </em>crossing experiment, where we observed
 pollen tubes growing through sections of styles in petri dishes. We did an
 11x11 cross, using 5 North
 American <em>Pedicularis </em>species and close- and
 distant-relatives that grow in the alpine plant communities they are a
 part of. We additionally did hand-pollinations in the field, then observed
 pollen tubes growing in styles by staining the styles with aniline blue.
 Finally, we measured the change in size of ovaries following the
 field-based hand pollinations. In our study, we used
 generalized linear models and generalized linear mixed models to assess
 whether or not phylogenetic distance was a significant predictor of the
 outcome of heterospecific pollination at each of the three stages
 described above. For the semi-in vivo study we used the raw data to
 calculate a proportion of trials in which pollen tubes were observed
 growing through styles. In the field-based study, we used an ordinal
 regression to assess the impact of phylogenetic distance on how far down
 the length of the style pollen tubes were observed. Finally, we normalized
 ovary area using the average ovary area from our control treatment (no
 pollen), and used a generalized linear model (gaussian distributed) to
 investigate the relationship between change in ovary size and phylogentic
 distance between crossing parents. 
description: # Cohen et al. Experimental Crosses Results
 [https://doi.org/10.5061/dryad.qv9s4mwqr](https://doi.org/10.5061/dryad.qv9s4mwqr) ## Description of the data and file structure This data is associated with the publication "Phylogeny does not predict the outcome of heterospecific pollen-pistil interactions in a species-rich alpine plant community" (Cohen et al., 2024), published in the* American Journal of Botany*. All of the data contained are the results from a series of cross-pollination experiments performed in the Colorado Rocky Mountains (Gothic, CO, USA) during the summers of 2022 and 2023. All information about study species are contained within the datasets. ### Files and variables #### File: Cohen\_et\_al\_2024\_Datasets.xlsx **Description:** File containing 5 individual sheets, each consisting of a dataset associated with one of the three parts of the study. The first sheet is a title sheet which will orient the reader to what is contained in sheets 2-5. The fifth sheet contains geographic information about the collection sites visited during this study. Missing values are usually indicated by an "X" Crosses are written maternal species x paternal species. Control ("no pollen") treatments are indicated by the species shorthand (two letter code for the genus and specific epithet, e.g. PB for* Pedicularis bracteosa*) and then the letters "NP", written as, for example, PBNP or PBxNP. ## Code/software No special code or software is needed to view the data. The data can be viewed in Microsoft Excel, Google Sheets, or Apple Numbers.