222 APPENDIX. 



iv. Mount a few pollen grains of the Dog-Daisy in a 

 drop of water or spirit and examine with a high power, 

 shewing on your sketch the spiny outer coat. 



v. Make a sketch of pollen grains which have been 

 allowed to germinate in a solution of sugar, shewing the 

 pollen grain and the pollen tube it has put forth. 



vi. Examine a spike of Plantain (Plantago), noting 

 that the flowers towards the apex have their long stigmas 

 ripe though no anthers are visible, while lower down the 

 anthers are mature and shedding their pollen. Make 

 sketches to illustrate this state of things (dichogamy). 



vii. Examine flowers of either Silene, Tropaeolum, or 

 Sweet William, noting that in the younger flowers the 

 anthers are mature, but the stigmas are not yet ready for 

 pollination, while the older ones have mature styles. The 

 flower is dichogamous, but is protandrous, not protogynous 

 like the Plantain. 



No. XIII. 



THE SEED. 



i. Make a sketch of a longitudinal section of the 

 stigma of (Enothera, the Evening Primrose, shewing 



a. triangular pollen grains on the margin of the 

 section ; 



b. pollen tubes growing from them and piercing the 

 tissues of the style on their way towards the ovules in the 

 ovary. 



