48 A HALF-HOUR WITH TEE 



bull's-eye condenser. If a seed of the red poppy 

 be now examined, it will be found to have a 

 uniform shape, and to be reticulated on its surface, 

 as seen at figure 129, plate 5. The seed of the 

 black mustard exhibits a surface apparently covered 

 with a delicate network, seen at figure 130. Some 

 seeds have deep and curved furrows on their sur- 

 faces, such as exhibited in figure 131. The great 

 snapdragon has a seed covered with irregular 

 projecting ridges, having a granuled appearance, 

 represented at figure 132. The seed of the chick- 

 weed presents a series of blunt projections, as in 

 figure 133. In the various forms of umbel- 

 bearing plants, the seeds adhere to the fruit, and 

 the fruit is commonly called the "seed." Such 

 are caraway, coriander, dill, and anise seeds. The 

 plants of this family are very common weeds in 

 our gardens and fields, and may be easily procured 

 for microscopic examination. Some of these fruits 

 are covered over with little hooks, seen at figure 

 134, whilst others present variously -formed ridges 

 and furrows, which are amongst the best means 

 for distr^uishing these plants the one from the 

 other. 



