III.] TROPJSOLUM. 7S 



To this family also belongs Tropaeolum, the com- 

 mon Nasturtium of our gardens. Here the honey is 

 contained in a long spur. The flower passes through 

 three well marked stages (Figs. 63—65). When it 

 first opens, as shown in Fig. 63, the anthers {a) are 

 unripe, the pistil (/) is short and immature. Soon, 

 however, one of the anthers ripens, opens, and 

 turns up, as shown in Fig. 64 a, a, so as to stand 

 directly in front of the opening to the tube; a 

 humble bee, therefore, or other insect of similar size. 



Fig. 64. — Flower of Tropteolum 7najor in the second stage. Some of the anthers 

 are now mature, and stand upright in front of the entrance to the spur. 



visiting the flower for the sake of its honey, could 

 not fail to rub some of the pollen off" on to her breast. 

 Shortly afterwards a second stamen ripens, and 

 assumes the same position, with the same result, and 

 the rest gradually follow. In flowers which I have 

 watched, this process occupies from three to seven 

 days, by which time the stamens have all come to 

 maturity, after which the anthers drop off", and the 

 filaments turn down as shown in Fig. 65, so as to be 

 well out of the way. It is now the turn of the pistil, 



