1918] DUDGEON—RUMEX CRISPUS 4II 
usually are not functional. The ovary usually is well developed, 
but the embryo sac is sterile by degeneration. The sepals and 
petals are about equally developed; they have performed their 
function in protecting the essential organs in the bud, and make no 
Fics. 17-21.—Types of mature flowers: fig. 17, transverse section, and fig. 19, 
longitudinal section of a functional staminate flower; ovary is present but sterile by 
degeneration; anther on left in fig. 19 nearly severed by disorganization of filament 
at a; fig. 18, transverse section, and fig. 20, longitudinal section of functional ovulate 
flower at early stage of embryo development; stamens degenerated and disappeared 
before flower opened; fig. 21, longitudinal section of a sterile flower; stamens obliter- 
ated and ovule sterile by degenerations; figs. 17, 18, X30; figs. 19-21, X18. 
