DOI: 10.5061/dryad.k98sf7mm3
title: Autorotating dispersal units of <i>Getonia floribunda</i> Roxb. (Combretaceae): Morphology, aerodynamics and geometrical significance

description: Dispersal units that continuously rotate while falling purely due to
 aerodynamic forces are called autorotating dispersal units. Single- to
 multi-winged forms of autorotating dispersal units occur in nature. The
 dispersal unit of Getonia floribunda Roxb. (Combretaceae) is an example of
 a multi-winged whirling diaspore that performs efficient autorotation in
 the air during wind dispersal. The present study aims to investigate the
 diaspore morphology, geometry, underlying principles, and reasons for the
 specificity of its autorotation during dispersal, and to find the
 morphological variations and geometrical significance. Plants and their
 diaspores from four locations in Northern Kerala, South India, were
 selected for this study. Detailed macromorphological, micromorphological,
 developmental, anatomical, aerodynamic, and experimental studies were
 performed on the collected diaspores. The results show that fruit
 diaspores with a distinct spatial configuration of persistent cyclically
 arranged tepals (perianth whorl) and distribution of the centre of mass
 along the middle vertical axis are the reasons for vertical autorotation
 or helicopter motion. Wing modification and paper model experiments prove
 that the wings have an intrinsically predetermined geometrical right-side
 leading-edge curvature, which is the reason for their distinct
 anticlockwise direction during autorotation. A significant variation in
 the morphological parameters of these diaspores was observed across
 locations. Still-airdrop tests and further statistical analysis show that
 the ing fold angle developed due to the distinct spatial configuration of
 the wings exhibited a significant, predictable relationship with descent
 rate and terminal velocity in this diaspore across locations. Thus, wing
 geometry has an impact on flight in these diaspores and demonstrates the
 relationship between the shape and fitness of natural flight organs.
description: # Autorotating dispersal units of *Getonia floribunda* Roxb.
 (Combretaceae): Morphology, aerodynamics, and geometrical significance
 Dataset DOI: [10.5061/dryad.k98sf7mm3](10.5061/dryad.k98sf7mm3) ##
 Description of the data and file structure The data was collected from
 dispersal units of four different locations in Northern Kerala, South
 India. Morphological measurements were carried out in the laboratory, and
 falling behaviours (descent rate, flipping or transition time, rotating
 time, and terminal velocity) were measured by conducting an experimental
 study, namely, the still-airdrop test explained by Seter and Rosen (1992),
 on samples from four locations separately. Then statistical analysis such
 as one-way ANOVA of morphological parameters such as weight, area, length,
 width, wing fold angle, and wing loading across samples of four location
 were performed to find any significant inter-location difference in
 morphological parameters; then bivariate correlation and multiple linear
 regression analysis were performed to find the significant factors
 affecting the descent rate and autorotation in this diaspore across
 locations. Regression and correlation analysis were performed using SPSS
 v20 (IBM) software, and all the data related to this analysis are
 incorporated in the manuscript and supplementary file itself. ANOVA and
 other statistical plots provided in the manuscript are done using the R
 software. The data codes used for this R analysis are provided here. ###
 Files and variables #### File 1:
 Data_for_Statistical_analysis_NJB-O4882.csv **Description:** **1. Table of
 data for statistical analysis:** data used for performing statistical
 analysis were provided in tabular form. First column of table includes
 name of locations; second column include sample numbers in each location;
 third column with weight of each diaspore in milligram; fourth column
 include the area of wings of the diaspore in millimeter square; fifth and
 sixth column with length and width of wings of diaspore in millimeter;
 seventh column include the fold angle of wings of each diaspore; eight
 column provided the wing loading of each diaspore were calculated by
 dividing weight of the diaspore in milligram divided by area of the wings
 in millimeter square; ninth column provided the descent rate (it is the
 distance travelled per second) of each diaspore during falling in meter
 per second; tenth column include the flipping time or time taken to change
 initial ori­entation of each diaspore in second; eleventh column include
 the time taken by each diaspore for autorotation in seconds and column
 twelve include the terminal velocity (it is the continu­ous fall rate in
 autorotation) of the diaspores in meter per second. #### File 2:
 Code_for_statistical_analysis-NJB-04882.txt **Description: 1. ANOVA
 codes:** R Codes used for performing ANOVA of weight, area, length, width,
 wing fold angle, and wing loading across samples of four locations. **2.
 Correlation plot codes:** R codes used for performing correlation and
 preparation of a multi-panel plot within a grid of four location samples.
 **3. Regression plot codes:** R codes used for performing regression
 analysis and preparation of a multi-panel plot within a grid of four
 location samples. ## Code/software The code provided in the data file can
 run by using R, version 4.5.1 (R Core Team 2025). The additional packages
 needed for running this code in R are ggplot2, dplyr, patchwork, a nd
 ggpubr.