= INTRODUCTION TO BOTANY. 
79. Thus, a Flower is : 
di-sepalous, tri-sepalous, &c., as there are 2, 3, &c., sepals. 
di-petalous, tri-petalous, &c., as there are 2, 3, &c., petals. 
di-androus, tri-androus, &c., as there are 2, 3, &c., stamens. 
di-gynous, tri-gynous, &c., as there are 2, 3, &c., separate carpels. __ 
di-merous, tri-merous, &c., if symmetrical, according as there are 2, 3, &c., 
in each whorl. 
80. Flowers are unsymmetrical or anisomerous, strictly speaking, when any one of 
_ the whorls has a different number of parts from the others; but when the pistils 
alone are reduced in number, the flower is still frequently called symmetrical, or 
isomerous, if the’ calyx, corolla, and staminal whorls have all the same number of | 
_ 81. 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. In descriptions, it is more especially irregularity of the corolla that is 
referred to ; a slight inequality in other parts does not prevent the flower being 
classed as regular, if corolla or perianth be regular. 
§ 9. The Perianth, and Calyx or Corolla. 
82. The Calyx or outer whorl of the perianth is usually green, smaller than the 
corolla, and of coarser texture; sometimes very minute, rudimentary, or obsolete 
altogether ; sometimes imperfectly whorled, or not whorled at all, or composed (as 
in Cactus) of a large number of sepals, of which the outer ones pass gradually into 
and the inner ones into petals. 
_ 88. The Corolla or inner whorl of the perianth is usually coloured, larger than the 
calyx, and of a more delicate texture, and in popular language is often called the 
. Its petals, except in double-flowers, are rarely indefinite in number, and the 
whorl more rarely broken than in the calyx. Sometimes the petals are very small, 
rudimentary, reduced to scales (as in Thymelec) or absent altogether. 
84, In very many cases the so-called simple-perianth is one in which the sepals 
and petals are nearly similar in form and texture, and present apparently a single 
whorl. The real nature of such a perianth may be detected by examining an un- 
opened flower-bud, when one half of the parts will be found placed outed of the 
others (as in Anthericum, Ornithogalum, Rumex, &c.), indicating an arrangement in 
two whorls, or calyx and corolla. Hence different authors may describe the same 
flower differently, either as having a single or a double perianth. 
85. In the following terms the prefixes expressive of the modifications of the 
corolla and its petals are equally applicable to the calyx and its sepals, or to the 
perianth and its ts. 
86. The Corolla is, 
mono-petalous (sometimes called gamopetalous), when the petals are united or 
soldered together, either entirely or at the base only, into a cup, tube, 
or ring. 
pelbetalons (or dialipetalous), when they are all separate or free from the 
very base. 
87. When the petals are partially united in a monopetalous corolla, the lower 
consolidated portion of the corolla is called the tube, whatever be its shape, and the 
free upper portions of the petals are called the teeth, lobes, or segments, according a8 
they are short or long in proportion to the whole length of the corolla. é 
88. The flat expanded portion of a petal, corresponding to the blade of the leaf, is 
called its limb or lamina ; and the stalk, corresponding to the petiole, its claw, When 
there is no claw, the petals are sessile. 
_ 89. The estivation of a corolla is the arrangement of the petals, or their free por- 
tions, in an unexpanded bud. It is valvate, when the edges of the petals touch, but 
do not over-lap ; imbricate, when the edges over-lap each other, at least near the 
top ; twisted, contorted, or convolute, when each petal obliquely overlaps the adjoining 
one on one side, and is overlapped by the adjoining one on the other side. In 
valvate wstivation, if the edges are much inflexed, eestivation is said to be in- 
duplicate ; involute, if the margins are inrolled ; and reduplicate, if the margins pro- 
ject outwards into salient angles ; plicate, when folded together in plaits ; crumple 
when puckered irregularly, as in the petals of a poppy. . 
