36 



HOW PLANTS EMPLOY INSECTS TO -VTORK FOE THEM, 



73. In FigWOrt or Scropliularia, and in many other flowers of which this may- 

 serve as an example, the work is done with much saving of pollen by calling in 



the aid of insects. Fig. 30 

 is an enlarged representa- 

 tion of one of the flowers, 

 as it appears throughout 

 the day of opening. The 

 style projects from the 

 gorge of the corolla, pre- 

 senting the stigma just 

 over the front edge. The 

 stamens are out of sight 

 and reach, and not yet 

 ready ; they lie recurved 

 below, as shown in Fig. 

 A day or two later the flower appears as in Fig. 32 : the style is flabby or 



Fig. so. Mower of Scrophularia nodosa, the first day. 31. Inside yiew of 

 it, the front lialf cut away. 32. Flower as it appears on tlie second day. 



31. 



withering, and the stigma dried up ; the stamens have straightened their fila- - 

 ments, and have brought up the four now opened anthers above the front edge of 

 the corolla, where the stigma was the day before. The bottom of the corolla- 

 cup contains some nectar. Honey-bees are attracted by it. When they visit a 

 flower in the state of Fig. 32, alighting as they do on the front lip, they get the 

 chest and legs well dusted with pollen, none of which has acted upon its own 

 stigma ; for that was dry and effete before these anthers opened. When the bee 

 passes to a freshly expanded flower, such as Fig. 30, the parts covered with pol- 

 len are sure to be brought against the fresh and active stigma, which cannot have 

 possibly been touched by any pollen of that flower, its anthers being still imma- 

 ture and hidden below. 



74. In some other Flowers the pollen is conveyed from an earlier to the stigma 

 of a later blossom, the anthers maturing and shedding their pollen before the 

 stigma is ready to receive any. A beautiful case of the sort, in which a move- 

 ment comes conspicuously into play, may be seen in Clei-odendron Tliompsonia', a 

 climbing shrub from tropical Afi'ica which blooms in our conservatories. Four 

 stamens with very long filaments and an equally long and slender style are rolled 

 up together in the corolla-bud. When this expands, the stamens straighten out 

 nearly in the line of the tube of the corolla, and their anthers open : the style 



