ELEMENTARY BOTANY. 
Xlll 
opposite to, or over the centre of the sepals ; those of the inner whorl (the inner 
stamens ) alternate with the outer ones, and are therefore opposite to the petals. If 
there is only one whorl of stamens, they most frequently alternate with the petals ; 
hut sometimes they are opposite the petals and alternate with the sepals. 
The Pistil forms the inner whorl ; its carpels usually alternate with the inner 
row of stamens. 
91. In an axillary or lateral flower the upper parts of each whorl (sepals, petals, 
stamens, or carpels) are those which are next to the main axis of the stems or 
branch, the lower parts those which are furthest from it ; the intermediate ones are 
said to be lateral. The words anterior (front) and posterior (back) are often used 
for lower and upper respectively, but their meaning is sometimes reversed if the 
writer supposes himself in the centre of the flower instead of outside of it. 
92. The number of parts in each whorl of a flower is expressed adjectively by the 
following numerals derived from the Greek : — 
mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octo-, ennea-, deca-, etc., poly-, 
1 -, 2 -, 3 -, 4 -, 5 -, 6 -, 7 -, 8 -, 10 -, many-, 
prefixed to a termination indicating the whorl referred to. 
93. Thus, a Flower is 
disepalous , trisepalous , tetrasepalous , polysepalous , etc., according as there are 
2, 3, 4, or many (or an indefinite number of) sepals. 
dipetalous , tripetalous , polypetalous , etc., according as there are 2, 3, or 
many petals. 
diandrous, triandrous , polyandrous , etc., according as there are 2, 3, or many 
stamens. 
dig ynous,. trig ynous, polygynous , etc., according as there are 2, 3, or many carpels. 
And generally (if symmetrical) dimerous, trimerous polymerous, etc., according 
as there are 2, 3, or many (or an indefinite number of) parts to each whorl. 
94. Flowers are imsymmetrical or anisomerous, strictly speaking, when any one of 
the whorls has a different number of parts from any other ; but when the carpels 
alone are reduced in number, the flower is still frequently called symmetrical or iso- 
merous, if the calyx, corolla, and staminal whorls have all the same number of parts. 
95. Flowers are irregular when the parts of any one of the whorls are unequal in 
size, dissimilar in shape, or do not spread regularly round the axis at equal dis- 
tances. It is however more especially irregularity of the corolla that is referred to 
in descriptions. A slight inequality in size or direction in the other whorls does 
not prevent the flower being classed as regular , if the corolla or perianth is con- 
spicuous and regular. 
9. The Calyx and Corolla , or Perianth. 
96. The Calyx (90) is usually green, and smaller than the corolla ; sometimes 
very minute, rudimentary, or wanting, sometimes very indistinctly whorled, or not 
whorled at all, or in two whorls, or composed of a large number of sepals, of which 
the outer ones pass gradually into bracts, and the inner ones into petals. 
97. The Corolla (90) is usually coloured, and of a more delicate texture than the 
calyx, and, in popular language, is often more specially meant by the flower. Its 
petals are more rarely in two whorls, or indefinite in number, and the whorl more 
rarely broken than in the case of the calyx, at least when the plant is in a natural 
state. Double flowers are in most cases an accidental deformity or monster in which 
the ordinary number of petals is multiplied by the conversion of stamens, sepals, 
or even carpels into petals, by the division of ordinary petals, or simply by the addi- 
tion of supernumerary ones. Petals are also sometimes very small, rudimentary, 
or entirely deficient. 
98. In very many cases, a so-called simple perianth (15) (of which the parts are 
usually called leaves or segments') is one in which the sepals and petals are similar in 
form and texture, and present apparently a single whorl. But if examined in the 
young bud, one half of the parts will generally be found to be placed outside the 
other half, and there will frequently be some slight difference in texture, size, and 
colour indicating to the close observer the presence of both calyx and corolla. 
