A CHAPTER TO STUDY. 7 



Regular Flowers are those that have the parts of each set, 

 the sepals and petals, alike in size and form. (Fig. 23.) Irregu- 

 lar Flowers are the reverse of regular. (Fig. 24.) 



It is sometimes found that only one set of floral leaves is 

 present. It is then regarded as the Calyx. Collectively the 

 floral envelope, or the protecting organs, is spoken of as the 

 Perianth ; but the word is mostly used in cases where the 

 calyx and corolla run into each other so that it is difficult to 

 distinguish them apart. The lily family have a perianth. 



The Stamens, or Fertilizing Organs, of the plant are 

 composed of two parts : the Filament, or stalk, which is use- 

 ful to uphold the Anther ; and the Anther, a tiny two-ceiled 

 box which contains the Pollen. The Pollen is the yellow 

 fertilizing powder which is the essential product of the 

 stamens. (Fig. 25.) 



Exserted Stamens are those that protrude from the 

 corolla. 



Included Stamens are those that are within the corolla. 



The Pistil, or Seed-Bearing Organ, is divided into three 

 parts : the Ovary, the Style, and the Stigma. (Fig. 26.) 



The Ovary is the lower expanded part of the pistil that 

 contains the Ovules, or undeveloped seeds. (Fig. 26.) 



The Style is the slender stalk that usually surmounts the 

 ovary. (Fig. 26.) 



The Stigma is the flat or variously formed body that ter- 

 minates the style. (Fig. 26.) Unlike the other organs of the 

 plant, it is not covered by a thin skin or epidermis. Its surface 

 is therefore moist and rough so that it readily receives and 

 holds the pollen when it is deposited upon its surface. 



Each tiny pollen grain that alights on the stigma sends out 

 a minute tube that pierces down through the style until it 

 reaches an ovule below, which it quickens into life. This is 

 known as the process of Fertilization. The ovules then de- 

 velop into Seeds, and the ovary enlarges into the Fruit, or 

 Seed Vessel. 



Cross-Fertilization is when the pollen of one flower is 



