124 



THE PAKTS OF THE FLOWEK 



192. Compound pis- 

 til of a St. John's- 

 wort. It has 5 car- 

 pels. 



254. Stamens bear the pollen, which is made up of 

 grains or spores, each spore usually being a single plant 

 cell. The stamen is of two parts, as readily 

 seen in Figs. 187, 188, 189, the enlarged 

 terminal part or anther, and the stalk or 

 filament. The filament is often so 

 short as to seem to be absent, and 

 the anther is then said to be 

 sessile. The anther bears the 

 pollen spores. It is made up 

 of two or four parts (known 

 as sporangia or spore -cases), which burst 



and discharge the 

 pollen. When 

 the pollen is shed, 

 the stamen dies. 



255. Pistils bear 

 the seeds. The pis- 

 til may be of one 

 part or compart- 

 ment, or of many parts. The different units or parts of 

 which it is composed are carpels. Each carpel is homo- 

 logous with a leaf. Each 

 carpel bears one or more 

 seeds. A pistil of one carpel 

 is simple; of two or more 

 carpels, compound. Usually 

 the structure of the pistil 

 may be determined by cut- 

 ting across the lower or seed- 

 bearing part. FigS. 190, 191, 101. The structure of a plum blossom. 

 .,__. , . se. sepals; p. petals; sta. stamens; 



192 explain. A flOWer may o. ovary; . style; st. stigma. The 



. . T / i pistil consists of the ovary, style, 



COntam One Carpel (Simple and stigma. It contains the seed 



. ..,\ , /-r-.. *,nn.\ part. The stamens are tipped with 



pistil) as the pea (Fig. 190); anthers, in which the pollen is 



T , borne. The ovary, o, ripens into 



several separate carpels or the fruit. 



193. Knotweed, a very common but inconspicuous plant 

 along hard walks and roads. Two flowers, en- 

 larged, are shown at the right. These flowers are 

 very small and borne in the axils of the leaves. 



