204 APPENDIX 
flower has four kinds of organs: pistils, stamens, petals, and sepals. 
In the lower groups the pistils and stamens are generally numerous 
and the parts of the flower are separately attached to the receptacle. 
7. The pistil or pistils are at the center of the flower. In the 
lower enlarged part of the pistil called the ovary are one or more 
cavities or cells which contain the ovules from which the seeds de- 
velop. The part of the wall of the cavity to which the ovules and 
seeds are attached is called the placenta. The stigma is the part of 
the pistil on which the pollen must fall to germinate and fertilize 
the ovules. The stigma is usually borne at the end of a stalk called 
the style. When this is short or wanting the stigma is sessile. 
8. The stamens are borne around the pistils. They consist of 
the stalks called filaments, at the ends of which are the anthers in 
the cavities or cells of which the pollen is found. 
9. Outside the stamens are two series of leaf-like organs mak- 
ing up the perianth. The inner whorl or corolla consists of petals 
which are usually some other color than green, and are usually the 
organs which make the flowers conspicuous and attractive. The 
outer whorl or calyx is made up of sepals which are usually green, 
but may resemble the petals in color and texture. The calyx pro- 
tects the inner more delicate organs in the bud. 
10. In the higher groups the flowers differ from this type in - 
various ways. One of these is by the omission of some of the organs. 
Thus one or both of the perianth whorles may be wanting. If the 
corolla is wanting the flowers are apetalous; if the calyx is also 
wanting, they are asepalous or achlamydeous. 
11. Frequently some of the flowers lack pistils and the rest 
lack stamens. Such flowers are imperfect, while those having both 
stamens and pistils are perfect. Flowers with stamens and lacking 
pistils are staminate, and those with pistils and lacking stamens are 
pistillate. Staminate flowers may have rudimentary pistils and 
pistillate flowers rudimentary stamens. A rudimentary stamen is 
called a staminodium. Flowers without either functional stamens or 
pistils are neutral. 
12. When staminate and pistillate flowers are produced on the 
same individual plant it is monecious, while if they are produced on 
different plants they are dicecious. Corn is monecious, the stami- 
nate flowers occurring in ‘the tassel and the pistillate in the ear. 
Cottonwood and box-elder are diccious and only the pistillate pro- 
duce seeds. Some plants have staminate and perfect flowers and 
are polygamous, or if the staminate are on separate plants, as in 
some grapes, they are called polygamo-diccious. 
13. Modifications of the flowers are often brought about by 
the union of organs of the same kind. Thus the sepals may unite 
and the flowers become gamosepalous. When not completely united 
the free parts are called teeth. Or the petals may be united and the 
flowers become gamopetalous. The stamen filaments are often 
united. If all are united into one group they are monadelphous and 
if in two groups diadelphous. In most of the composites the anthers 
are united into a tube around the style, that is, they are syngenesious. 
14. The pistil often consists of several united carpels. All de- 
grees of union occur, from a slight union at the base to complete 
