CALYX. 
61 
when not green, it is said to le colored. This organ is an expansion of thb bark oj 
the flower-stalk, as appears from its color and texture. The calyx usually envelops 
the corolla, previous to its expansion, and afterward remains below or around its 
base. 
h. In the calyx are three parts, very distinct in calyces which are long and cylin- 
dric: these are, 1st, the tube, which rises fi'om the base ; 2d, the throat, above the 
tube ; and 3d, the mouth, or the upper and expanded part ; the tube of the calyx 
is cylindrie in the pink, and prismatic in the stramonium. 
c. The position of the calyx with respect to the ovary offers an important mark of 
distinction between different genera, and also between different natural families of 
plants. The calyx is said to be stiperior when it is situated on the summit of the 
ovary, as in the apple ; it is inferior when situated below the ovary, as in the pink. 
In many plants the calyx is neither superior nor inferior, but is situated around 
the ovary. When the calyx drops off before the flower fully expands, it is called 
caducous ; the petals of the poppy are, at first, inclosed in a calyx of two sepals, 
but those fall off before the flower is full blown. When the calyx withers, and 
drops off with the corolla, it is called deciduous ; when it remains until the fruit is 
matured, it is called persistent. Upon a pea-pod the calyx may be seen as perfect 
as it was in the blossom. The tube of the calyx is sometimes united to the pistil, 
and enlarges so as to form a part of the fruit, as in the apple, pear, <fec., where the 
dry sepals may be seen on the summit of the fruit. In the wintergreen {Gaulthe- 
ria procumbens) the berries consist of the inflated, juicy sepals. 
68. Perianth (from the Greek, jperi^ around, antlios^ flower). 
This is the only real cnp or calyx ; — in the rose it is 'ww-form, 
with leaf-like divisions at the top. In the pink, the perianth is 
long and tubular, having the border dentate or toothed. The 
liollyhock has a double perianth. Hie term perianth is used 
when a flower has but one envelope, as in the tulip ; it is often 
difficult to determine whether this envelope should be called a 
corolla or calyx. Involucrum (from the Latin, involvo^ to 
wrap up) ; this kind of calyx is usually found at the base of an 
umbel, as in the carrot. It is composed of several bracts, some- 
times very small, crowded into a whorl. The involucrum is 
said to be universal^ when it belongs equally to the whole of 
an aggregate flower; dindi partial when it incloses one floret, 
which with others constitutes a compound or aggregate flower. 
The term involucrum is also applied to the membraneous cover- 
ing ill the fructification of ferns. Ament or catkin^- (by some 
classed as a mode of inflorescence) consists of many chafly 
Bcales, ranged along a thread-like stalk or receptacle ; each 
scale protects one or more of the stamens or pistils, the whole 
forming one aggregate flower. The ament is common to forest- 
trees, as the oak and chestnut ; and is also found upon the wil- 
low and poplar. In some trees the staminate flowers are inclo- 
sed in an ament, and the pistillate in a perianth. The Spatha^ 
or sheath, first incloses the flower, and, when this expands, 
bursts lengthwise and often appears at some distance below it. 
This is, by some botanists, considered as a jpetaloid hract. It 
* See Fig. 135, a a. + See Fig 95. 
b. Parts o the calyx — c. Position witli respect to ilie ovary. — 68. Perianth — Involucrum — Ament- 
Hpatha. 
