Seed characters are those relating to the "unit[s] of sexual reproduction developed from the fertilised ovule" [Hickey et al, 2000].
The next step is to select one of the characters from the list on the left-hand side in order to view definitions of its various features.
Here is a list of the possible seed characters to choose from:
endosperm type (ruminate or not)
presence of testa
testa surface (smooth, with spines or with tubercles)
testa colour pattern (homogeneous or conspicuously colour patterned)
area of scar to testa %
scar position (basal, lateral or apical)