Data on involucre colour and indumentum intensity from Scorzoneroides autumnalis (Asteraceae)
Cite this dataset
Andersson, Stefan et al. (2024). Data on involucre colour and indumentum intensity from Scorzoneroides autumnalis (Asteraceae) [Dataset]. Dryad. https://doi.org/10.5061/dryad.m37pvmd97
Abstract
Scorzoneroides autumnalis is a highly polymorphic perennial with several described infraspecific taxa, largely differing in involucre colour and indumentum intensity. Here, we examine the role of ecotypic divergence and phenotypic plasticity in shaping large-scale geographical variation in these characters. We collected phenotypic data from herbarium specimens and garden-grown plants of S. autumnalis, representing several habitats throughout Scandinavia and Iceland, and subjected progenies from controlled crosses within a subset of the common garden material to different temperature regimes to assess patterns of phenotypic plasticity. Our results strongly suggest that colour and indumentum of involucral bracts, as well as the size of capitula (measured by ligule length), are environmentally plastic and much affected by temperature. Reduced temperature resulted in significantly larger capitula, with both thicker and darker involucre indumentum. Since dark colouration, dense indumentum and large floral structures have been shown to facilitate heat retention and insect visitation in other plant species growing in cold climate, we hypothesize that plants of S. autumnalis benefit from possessing these features under cool conditions, and that much of the geographical variation in capitulum characters reflects adaptive phenotypic plasticity rather than ecotypic divergence. For this reason, we deem these characters to have a low taxonomic value for distinguishing infraspecific taxa within S. autumnalis.
README: Data on involucre colour and indumentum intensity from Scorzoneroides autumnalis (Asteraceae)
https://doi.org/10.5061/dryad.m37pvmd97
The present file contains three data sets, called Herbarium data, Common-garden data and Temperature experiment data, used in a study of geographical variation of two capitulum characters (indumentum intensity and degree of colouration) in Scorzoneroides autumnalis (Asteraceae), entitled “Dressed for the occasion! – Ecotypic divergence, phenotypic plasticity, and taxonomic value of capitulum characters of Scorzoneroides autumnalis (Asteraceae)”, Nordic Journal of Botany, DOI: 10.1111/njb.04211.
The herbarium data refer to specimens from herbaria in Sweden (GB, LD, OHN, S, UME, UPS), Norway (KMN, O, TROM, NTNU), Iceland (ICEL, AMNH) and Denmark (C). Remaining data refer to plants cultivated at Lund University, Sweden.
Each row represents data from a separate individual.
Definition of column headings:
Region:
The main region from which a herbarium specimen or common-garden individual originated. South = southern part of Scandinavia, Central = central part of Scandinavia, North = northern part Scandinavia, and Iceland = Iceland.
Latitude/longitude:
The latitude and longitude of the locality from which a herbarium specimen or common-garden individual originated, based on the WSG 84 system.
Altitude:
The elevation of the locality from which a herbarium specimen or common-garden individual originated, estimated from latitudinal and longitudinal coordinates using the ASTER Global Digital Elevation model.
Habitat:
The habitat at the locality from which a common-garden individual originated.
Temperature:
The temperature settings used for the climate chamber in which an individual was placed. All chambers were set to 60% air humidity and had the following daylight scheme: 4-hour night with no light; 5-hour dawn with 50% light intensity; 10-hour day with full light; and 5-hour dusk with 50% light intensity.
Family:
The full-sib family of an individual used in the temperature gradient experiment. Each family was derived from a particular cross between two parent plants representing the same or different populations in the common-garden experiment.
Colour grade:
The degree of colouration on the involucral bracts recorded for an individual: 1 = pale green – bracts lighter than the stem and base of involucre; 2 = light green – bracts of the same colour as stem and base of involucre; 3 = green – quarter to half of the bracts darker than stem and base of involucre; 4 = dark green – majority of the bracts darker than stem or base; 5 = blackish green to black – the bracts almost uniformly and considerably darker than stem or base
Indumentum grade:
The indumentum intensity (hairiness) on the involucral bracts recorded for an individual: 1 = hairless – no hairs visible with the naked eye; 2 = puberulous to pilose – hairs clearly separated and visible with the naked eye; = pubescent – hairs covering the involucral bracts and making their edges difficult to see against the background; 4 = felted to woolly – hairs sufficiently dense to make the individual bracts impossible to discern
A dot within a dataset denotes lack of data, caused by the absence of capitula (individuals that remained vegetative) or the death of the individual prior to measurement.
Contact data:
Stefan Andersson
Department of Biology
University of Lund
Sölvegatan 37
S-223 62 Lund
Sweden
Methods
The data represents unprocessed raw data, collected by scoring dried capitula (flower heads) on specimens from 13 Nordic herbaria, plants grown in a common garden at Lund University (2019) and plants grown in climate chamber at Lund University (2021) for involucre colour and indumentum intensity, based on predetermined grading categories 1-5 for colour and 1-4 for indumentum).