FLOWERS 127 
adjacent cycles; that is, each petal opposite a space between 
two sepals, each stamen opposite a space between two petals, 
and so on. Very often this alternate ar- 
rangement of the members of successive 
whorls is less evident because one or more 
whorls have more numerous or fewer parts 
than the others, as in the case of the butter- 
cups and crowfoots (fig. 103), roses, and 
Fie. 104. Flower of many 
lizard’s-tail, with no 
calyx or corolla 
After Engler 
ers are 
other familiar flowers. In many 
cases, as in the knotgrass (fig. 125), only 
one sct of floral leaves occurs. Such flow- 
said to lack petals and are known as 
apetalous. Some flowers, as those of the lizard’s-tail (fig. 104) 
and the willow (fig. 105), 
are wholly destitute of 
calyx and corolla. 
117. Staminate flow- 
ers and pistillate flowers. 
Such flowers as are shown 
in figures 101-104, con- 
taining both stamens and 
pistils, are said to be 
biserualt Those which 
contain stamens but not 
pistils or pistils but not 
stamens, like those of the 
willow (fig. 105), are said 
to be uniserual, Many 
families of dicotyledon- 
ous trees and shrubs, 
such as the Willow fam- 
ily, the Oak family, and 
others, have unisexual 
D 
Fie. 105. Dicecious flowers of white willow 
(Salix alba) 
A, staminate catkin, natural size; B, pistillate 
catkin, natural size ; C, staminate flower, mag- 
nified; D, pistillate flower, magnified. After 
Cosson and De Saint-Pierre 
1 The flower itself is not sexual at all, as will appear later, but these 
terms have come into general use, and their application to the two kinds of 
flower seems likely to continue. 
