OUTLINES OF BOTANY. XXVIII 
direction in the other whorls does not prevent the flower being classed as 
regular, if the corolla or perianth is conspicuous 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 indis- 
tinetly 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 tex. 
ture 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 addition of super- 
numerary ones. Petals are also sometimes very small, rudimentary, or en- 
tirely 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 gene- 
rally 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. Hence much discrepancy 
in descriptive works. Where one botanist describes a simple perianth of 
six segments, another will speak of a double perianth of three sepals and 
three petals. 
99. The following terms and prefixes, expressive of the modifications of 
form and arrangement of the corolla and its petals, are equally applicable’ 
to the calyx and its sepals, and to the simple perianth and its segments. 
100. The Corolla is said to be monopetalous when the petals are united, 
either entirely or at the base only, into a cup, tube, or ring; polypetalous 
_ when they are all free from the base. These expressions, established by a 
long usage, are not strictly correct, for monopetalous (consisting of a single 
petal) should apply rather to a corolla really reduced to a single petal, 
which would then be on one side of the axis; and polypetalous is some- 
times used more appropriately for a corolla with an indefinite number of 
petals. Some modern botanists have, therefore, proposed the term gamo- 
petalous for the corolla with united petals, and dialypetalous for that with 
se petals; but the old-established expressions are still the most generally 
used, 
101. When the petals are partially united, the lower entire portion of 
the corolla is called the twbe, whatever be its shape, and the free portions of 
the petals are called the teeth, lobes, or segments (39), according as they are 
short or long in proportion to the whole length of the corolla. When the 
‘tube is excessively short, the petals appear at first sight free, but their slight 
union at the base must be carefully attended to, being of importance in 
classification. 
102. The Zstivation of a corolla is the arrangement of the petals, or 
of such portion of them as is free, in the unexpanded bud. It is 
