DOI: 10.5061/dryad.8931zcrt5
title: Population genetics and comparative morphology of two serpentine Phlox species

description: Hybridization between rare and widespread species can result in loss of
 genetic integrity for the rarer species, which can have management and
 conservation implications. One rare species, Phlox hirsuta, is a
 serpentine endemic in northern California, and it frequently co-occurs
 with a widespread congener, P. speciosa. Putative hybrids were recognized
 based on intermediate morphology, so the possibility of hybridization was
 explored using floral morphological and molecular data. Ninety-eight
 individuals of P. hirsuta and P. speciosa were collected from each of
 three populations, and floral features were measured and compared. Eleven
 microsatellite loci were amplified for species and putative hybrids, and
 inter- and intraspecific genetic diversity and relationships were
 investigated with multiple methods. Variation in morphological and
 molecular data was recognized. Floral variation was greater for P. hirsuta
 than P. speciosa. Putative hybrids were genetically allied with P.
 speciosa, but two individuals of P. hirsuta were resolved to have genetic
 similarity with P. speciosa. While hybridization is possible between the
 species, it is uncommon and appears to be primarily unidirectional, with
 P. speciosa as the hypothesized male parent and P. hirsuta as the
 hypothesized female parent. The small number of recognized hybrids may be
 due to ineffective interspecific pollination, early acting inbreeding
 depression, hybrids being less fit than parents, and/or small sample
 sizes. Reinforcement does not appear to play a role in secondary contact
 between species. Both microsatellite loci and floral morphology varied
 across the small geographic range of P. hirsuta, suggesting local
 differentiation and adaptation are possible over short distances.
description: Flowers of 98 individuals of each of Phlox hirsuta and P.
 speciosa were collected from three populations where both species
 co-occur: China Hill, Greenhorn, and Soap Creek Ridge (Fig. 1).  Flowers
 were preserved in 100% EtOH. Flowers were dissected under a Nikon SMZ800N
 stereomicroscope, and images of the corolla, androecium, and gynoecium
 were captured using NIS-Elements software with a Nikon DS-Fi2 digital
 camera.  Using the NIS-Elements software, measurements were made for
 multiple floral features. Leaf material of P. hirsuta
 was collected, in 2013, from 38-42 individuals in each of four putative
 populations – Cracker Gulch (CG), China Hill (CH), Greenhorn (G), Soap
 Creek Ridge (SC) (Fig. 1) – and in 2016, leaf material for P. speciosaand
 putative hybrids of the two species was collected from seven and four
 individuals from two populations (CH and SC), respectively.  The latitude
 and longitude were recorded for each collection. Leaf material was dried
 in silica gel and stored at 4° C.  Leaf material for 186 samples from the
 four populations of P. hirsuta, two populations of P. speciosa, and
 putative hybrids of the two species was sent to the biotechnology company
 Eurofins BioDiagnostics for DNA isolation and microsatellite amplification
 and sequencing using an ABI 3730XL, with a GeneScan 500LIZ size standard.
 Twelve microsatellite loci that were identified for related species of
 Phlox were amplified.
description: # Population genetics and comparative morphology of two serpentine Phlox
 species
 [https://doi.org/10.5061/dryad.8931zcrt5](https://doi.org/10.5061/dryad.8931zcrt5) ## Description of the data and file structure PHLOX_MICROSATS_STRUCTURE.txt is one of the STRUCTURE datasets used in the population genetic analyses. Samples are in the first column, population identifiers are in the second column, and the other column have allele lengths. The first row includes the names of loci. CG is Cracker Gulch, CH is China Hill, G is Greenhorn, and SC is Soap Creek Ridge. All individuals are members of Phlox hirsuta, except those labelled hybrid (putative hybrids) and P. speciosa, which are individuals of Phlox speciosa. PHLOX_FLORAL_MORPHOLOGY.csv is the datafile used for morphometric analyses. The first row includes the samples and the measurements used (all in millimeters). Anther length, filament length, and filament attachment height collectively equal anther height, and ovary length, style length, and stigma length collectively equal stigma height. GH is P. hirsuta from Greenhorn, CH is P. hirsuta from China Hill, SH is P. hirsuta from Soap Creek Ridge, GS is P. speciosa from Greenhorn, CS is P. speciosa from China Hill, and SS is P. speciosa from Soap Creek Ridge. Missing data code: null.