ce es 
REPRODUCTIVE ORGANS OF PLANTS. 119 
When flowers grow from an elongated flower-stalk without distinct 
stalks of their own, or when their separate stalks are very short, they 
form a spike, as in the plantain or rib-grass ; when the separate stalks are 
of notable length, we have a racente,tas in the hyacinth. Both spikes and 
racemes are often compound by the branching of the principal stalk. 
Compound spikes sometimes have their branches or spikelets, closely 
compacted into a head of flowers. Spikes of a close form, having a scal 
bract under each flower, are called cathins.2, When the lower flowers of a 
raceme are supported on longer stalks than the upper, so that all the 
flowers are nearly on a level at top, as in the hawthorn, we have a corymb? 
When all the branches of a raceme spring from nearly the same point, 
and diverge in a radiating manner, they form an wmbel.4 An example of 
the umbel may be seen in the cowslip, but this form of inflorescence is 
particularly characteristic of a great order of plants, therefore called 
Umbellifere or umbel-bearers, of which the carrot, the cow-parsnip, and 
the hemlock are familiar examples. In all these forms of inflorescence, 
the first flowers which expand are the lowest or outermost.. There are 
plants, however, in which the first flowers produced are the most central. 
In this case, the flowers are often produced on stalks which grow up 
together in nearly equal length, and form what is called a cyme,® an 
example of which may be seen in the elder. 
Flowers—Parts of the Flower.—Ilowers are produced from buds as leaves 
are. The parts of a flower are, in fact, leaves changed as to their form 
and use, but produced and arranged after the manner of leaves ; and their 
true nature is shewn by their sometimes becoming leaves again in what 
are called monstrosities of plants, which often occur when a plant receives 
excess of nourishment through cultivation. They arise from the stalk 
of the flower, as leaves arise from the stem, but form definite groups very 
distinct in character and use. These groups are generally whorls, even 
when the leaves of the plant are not whorled. The first or outermost whorl 
_(g, fig. 78) forms tlie calyx [Greek, a cup], and commonly consists of small 
green leaves called sepals, which are often united so as to forma kind of cup. 
The use of the calyx seems to be the protection of the more tender parts 
of the flower, and it encloses them all when in bud. The second whorl 
of leaves, which may either be quite distinct, or may unite into a cup, 
bell, or tube, is the corolla ® (h, fig. 78), generally the most beautiful part of 
the flower ; the leaves which form it, called petals,’ being delicate and finely 
-. coloured. The calyx, however, sometimes assumes an appearance similar 
to that of the corolla; and in some plants, these whorls grow so closely 
1 From Latin racemus, a cluster of grapes. 5 From Latin cyma, a sprout. 
2 From the resemblance of a cluster to a cat’s tail. 6 Latin, ‘little crown,’ diminutive of 
3 From Latin corymbus, a cluster of fruit. corona, a crown. 
4°A little shade,’ from Latin wmbra, a shade. 7 Latin petalum, a leaf. 
