We have applied experimental evolution to a source population of the dioecious Mercurialis annua, which was divided into five populations that underwent three generations at low-density and five others at high-density. After this contrasted evolution, we have grown seeds from these ten experimental populations in a common garden to assess the sex-specific evolutionary responses to plant density. In the common garden, we have measured both vegetative and reproductive traits in male and female plants of each experimental populations, and in the source population (termed G0 in the dataset). A brief description of each morphological trait measured in provided in the dataset.

BLOC	Plants were grown in two different blocs
POSITION	Plant position within the bloc 
x, y	x, y coordinates in meters
IND	Plant individual name
Sex	Plant sex
POP	Population name
TREAT	Treatment name : HIGH, high-density, LOW low-density and G0, the source population
Height_young	Plant height at a young age (cm)
Height_interm	Plant height at an intermediate age (cm)
Height_old	Plant height at an old age (cm)
Diameter	Plant canopy diameter (cm)
L1, L2	Length of the two lowest ramifications down the plant (cm)
Lmean	Mean length of the two lowest ramification down the plant (cm)
P1, …, P5	Length of the five male peduncles sampled on the fifth highest nodes of the primary axis (cm)
MeanPed	Mean peduncle length (cm) 
Nb_ped_tot	Total number of inflorescences (in males) 
Biomass	Dry mass of vegetative tissues (g)
Mass_repro	Dry mass of the reproductive tissues (seeds for females and inflorescences for males, g)
Nb_seeds	Number of seed produced (in females)